From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EAAAF2EE61C; Wed, 27 Aug 2025 20:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=kTvavCsriIiHc2lpP2zvp+H3owpios//BOWlyskgWvx9y436OOfHQyeVWw5qS6+haTJ19tMuiKc0+r1ZaNuzMRTr2HvZKSvCEis42gwuYagyb0XvCO/e4kCzVOvVGR1kbx0LpAp+Xp2rU9gO4am82lPd3L+jP0a4DwtcAmlg8m0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; c=relaxed/simple; bh=8N2d9jIRzG/27NeBhv8n4ni+hFpJLErKf4yPWJZA+Hs=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ZlOHThLMtb4O98ANEOTIUExo75L5tIftz3r9j7fE8A6npsxkFxCMYNK7+TinrMez68mQfHgiEAMHKax4yBKvLZNi3U/0GaNaXv0xZaC3vi2HWtK0bbDqIu9gT3m0R0QIFCZm/GHEwmISfvfeA4Uifkc1wIWg/va08KQWaQ2PYBQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XJkW8sIC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XJkW8sIC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FF2AC4CEF7; Wed, 27 Aug 2025 20:24:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326261; bh=8N2d9jIRzG/27NeBhv8n4ni+hFpJLErKf4yPWJZA+Hs=; h=Date:From:To:Cc:Subject:References:From; b=XJkW8sICm6eRg1hVqJnlwAMqT/8N8iYTQIGujM8FktgvkhT4MIe/wLu8OEuGehyH5 8GT2J9KnM2SjPz+rQixUW7KU5NBkozPfd3SJ3+vRNubQ5q5Y4CiQa5wDD7yxjjJt4S vv+tBjBamux4ZJncmf95mmxV50nX1vWtIaiSE5IZll8bMdiMM1ZSVsNtlXSVZRUTNh 2RgxUWyW7CiT7acN41WzpKPxJXyY79vLXDyyymd77/QDRH1cC9MEC8Mjf9ubvSgtzB bxoaWiVF0eEF1AZ9wKtnzkQkhVVGNcoWvf9tdmFwe/5GZItd08ib2WUnX2gbWfO8WA QILCBR4ZiP3wg== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhE-00000003kwB-1n6z; Wed, 27 Aug 2025 16:24:40 -0400 Message-ID: <20250827202440.264683085@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:49 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 01/11] unwind_user/sframe: Add support for reading .sframe headers References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf In preparation for unwinding user space stacks with sframe, add basic sframe compile infrastructure and support for reading the .sframe section header. sframe_add_section() reads the header and unconditionally returns an error, so it's not very useful yet. A subsequent patch will improve that. Link: https://lore.kernel.org/all/f27e8463783febfa0dabb0432a3dd6be8ad98412.= 1737511963.git.jpoimboe@kernel.org/ Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- MAINTAINERS | 1 + arch/Kconfig | 3 + include/linux/sframe.h | 40 ++++++++++++ kernel/unwind/Makefile | 3 +- kernel/unwind/sframe.c | 136 +++++++++++++++++++++++++++++++++++++++++ kernel/unwind/sframe.h | 71 +++++++++++++++++++++ 6 files changed, 253 insertions(+), 1 deletion(-) create mode 100644 include/linux/sframe.h create mode 100644 kernel/unwind/sframe.c create mode 100644 kernel/unwind/sframe.h diff --git a/MAINTAINERS b/MAINTAINERS index fed6cd812d79..42b0fb83516a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -26333,6 +26333,7 @@ USERSPACE STACK UNWINDING M: Josh Poimboeuf M: Steven Rostedt S: Maintained +F: include/linux/sframe.h F: include/linux/unwind*.h F: kernel/unwind/ =20 diff --git a/arch/Kconfig b/arch/Kconfig index d1b4ffd6e085..69fcabf53088 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -451,6 +451,9 @@ config HAVE_UNWIND_USER_FP bool select UNWIND_USER =20 +config HAVE_UNWIND_USER_SFRAME + bool + config HAVE_PERF_REGS bool help diff --git a/include/linux/sframe.h b/include/linux/sframe.h new file mode 100644 index 000000000000..0584f661f698 --- /dev/null +++ b/include/linux/sframe.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SFRAME_H +#define _LINUX_SFRAME_H + +#include +#include + +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + +struct sframe_section { + unsigned long sframe_start; + unsigned long sframe_end; + unsigned long text_start; + unsigned long text_end; + + unsigned long fdes_start; + unsigned long fres_start; + unsigned long fres_end; + unsigned int num_fdes; + + signed char ra_off; + signed char fp_off; +}; + +extern int sframe_add_section(unsigned long sframe_start, unsigned long sf= rame_end, + unsigned long text_start, unsigned long text_end); +extern int sframe_remove_section(unsigned long sframe_addr); + +#else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */ + +static inline int sframe_add_section(unsigned long sframe_start, unsigned = long sframe_end, + unsigned long text_start, unsigned long text_end) +{ + return -ENOSYS; +} +static inline int sframe_remove_section(unsigned long sframe_addr) { retur= n -ENOSYS; } + +#endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */ + +#endif /* _LINUX_SFRAME_H */ diff --git a/kernel/unwind/Makefile b/kernel/unwind/Makefile index eae37bea54fd..146038165865 100644 --- a/kernel/unwind/Makefile +++ b/kernel/unwind/Makefile @@ -1 +1,2 @@ - obj-$(CONFIG_UNWIND_USER) +=3D user.o deferred.o + obj-$(CONFIG_UNWIND_USER) +=3D user.o deferred.o + obj-$(CONFIG_HAVE_UNWIND_USER_SFRAME) +=3D sframe.o diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c new file mode 100644 index 000000000000..20287f795b36 --- /dev/null +++ b/kernel/unwind/sframe.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Userspace sframe access functions + */ + +#define pr_fmt(fmt) "sframe: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "sframe.h" + +#define dbg(fmt, ...) \ + pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) + +static void free_section(struct sframe_section *sec) +{ + kfree(sec); +} + +static int sframe_read_header(struct sframe_section *sec) +{ + unsigned long header_end, fdes_start, fdes_end, fres_start, fres_end; + struct sframe_header shdr; + unsigned int num_fdes; + + if (copy_from_user(&shdr, (void __user *)sec->sframe_start, sizeof(shdr))= ) { + dbg("header usercopy failed\n"); + return -EFAULT; + } + + if (shdr.preamble.magic !=3D SFRAME_MAGIC || + shdr.preamble.version !=3D SFRAME_VERSION_2 || + !(shdr.preamble.flags & SFRAME_F_FDE_SORTED) || + shdr.auxhdr_len) { + dbg("bad/unsupported sframe header\n"); + return -EINVAL; + } + + if (!shdr.num_fdes || !shdr.num_fres) { + dbg("no fde/fre entries\n"); + return -EINVAL; + } + + header_end =3D sec->sframe_start + SFRAME_HEADER_SIZE(shdr); + if (header_end >=3D sec->sframe_end) { + dbg("header doesn't fit in section\n"); + return -EINVAL; + } + + num_fdes =3D shdr.num_fdes; + fdes_start =3D header_end + shdr.fdes_off; + fdes_end =3D fdes_start + (num_fdes * sizeof(struct sframe_fde)); + + fres_start =3D header_end + shdr.fres_off; + fres_end =3D fres_start + shdr.fre_len; + + if (fres_start < fdes_end || fres_end > sec->sframe_end) { + dbg("inconsistent fde/fre offsets\n"); + return -EINVAL; + } + + sec->num_fdes =3D num_fdes; + sec->fdes_start =3D fdes_start; + sec->fres_start =3D fres_start; + sec->fres_end =3D fres_end; + + sec->ra_off =3D shdr.cfa_fixed_ra_offset; + sec->fp_off =3D shdr.cfa_fixed_fp_offset; + + return 0; +} + +int sframe_add_section(unsigned long sframe_start, unsigned long sframe_en= d, + unsigned long text_start, unsigned long text_end) +{ + struct maple_tree *sframe_mt =3D ¤t->mm->sframe_mt; + struct vm_area_struct *sframe_vma, *text_vma; + struct mm_struct *mm =3D current->mm; + struct sframe_section *sec; + int ret; + + if (!sframe_start || !sframe_end || !text_start || !text_end) { + dbg("zero-length sframe/text address\n"); + return -EINVAL; + } + + scoped_guard(mmap_read_lock, mm) { + sframe_vma =3D vma_lookup(mm, sframe_start); + if (!sframe_vma || sframe_end > sframe_vma->vm_end) { + dbg("bad sframe address (0x%lx - 0x%lx)\n", + sframe_start, sframe_end); + return -EINVAL; + } + + text_vma =3D vma_lookup(mm, text_start); + if (!text_vma || + !(text_vma->vm_flags & VM_EXEC) || + text_end > text_vma->vm_end) { + dbg("bad text address (0x%lx - 0x%lx)\n", + text_start, text_end); + return -EINVAL; + } + } + + sec =3D kzalloc(sizeof(*sec), GFP_KERNEL); + if (!sec) + return -ENOMEM; + + sec->sframe_start =3D sframe_start; + sec->sframe_end =3D sframe_end; + sec->text_start =3D text_start; + sec->text_end =3D text_end; + + ret =3D sframe_read_header(sec); + if (ret) + goto err_free; + + /* TODO nowhere to store it yet - just free it and return an error */ + ret =3D -ENOSYS; + +err_free: + free_section(sec); + return ret; +} + +int sframe_remove_section(unsigned long sframe_start) +{ + return -ENOSYS; +} diff --git a/kernel/unwind/sframe.h b/kernel/unwind/sframe.h new file mode 100644 index 000000000000..e9bfccfaf5b4 --- /dev/null +++ b/kernel/unwind/sframe.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * From https://www.sourceware.org/binutils/docs/sframe-spec.html + */ +#ifndef _SFRAME_H +#define _SFRAME_H + +#include + +#define SFRAME_VERSION_1 1 +#define SFRAME_VERSION_2 2 +#define SFRAME_MAGIC 0xdee2 + +#define SFRAME_F_FDE_SORTED 0x1 +#define SFRAME_F_FRAME_POINTER 0x2 + +#define SFRAME_ABI_AARCH64_ENDIAN_BIG 1 +#define SFRAME_ABI_AARCH64_ENDIAN_LITTLE 2 +#define SFRAME_ABI_AMD64_ENDIAN_LITTLE 3 + +#define SFRAME_FDE_TYPE_PCINC 0 +#define SFRAME_FDE_TYPE_PCMASK 1 + +struct sframe_preamble { + u16 magic; + u8 version; + u8 flags; +} __packed; + +struct sframe_header { + struct sframe_preamble preamble; + u8 abi_arch; + s8 cfa_fixed_fp_offset; + s8 cfa_fixed_ra_offset; + u8 auxhdr_len; + u32 num_fdes; + u32 num_fres; + u32 fre_len; + u32 fdes_off; + u32 fres_off; +} __packed; + +#define SFRAME_HEADER_SIZE(header) \ + ((sizeof(struct sframe_header) + header.auxhdr_len)) + +#define SFRAME_AARCH64_PAUTH_KEY_A 0 +#define SFRAME_AARCH64_PAUTH_KEY_B 1 + +struct sframe_fde { + s32 start_addr; + u32 func_size; + u32 fres_off; + u32 fres_num; + u8 info; + u8 rep_size; + u16 padding; +} __packed; + +#define SFRAME_FUNC_FRE_TYPE(data) (data & 0xf) +#define SFRAME_FUNC_FDE_TYPE(data) ((data >> 4) & 0x1) +#define SFRAME_FUNC_PAUTH_KEY(data) ((data >> 5) & 0x1) + +#define SFRAME_BASE_REG_FP 0 +#define SFRAME_BASE_REG_SP 1 + +#define SFRAME_FRE_CFA_BASE_REG_ID(data) (data & 0x1) +#define SFRAME_FRE_OFFSET_COUNT(data) ((data >> 1) & 0xf) +#define SFRAME_FRE_OFFSET_SIZE(data) ((data >> 5) & 0x3) +#define SFRAME_FRE_MANGLED_RA_P(data) ((data >> 7) & 0x1) + +#endif /* _SFRAME_H */ --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 683EB2FDC53; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X5TEmnBa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8F55C113CF; Wed, 27 Aug 2025 20:24:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326261; bh=x3ujmxrXMW5vw5xWUC2Eexk5U5sWoGVjWxdi+GniSVQ=; h=Date:From:To:Cc:Subject:References:From; b=X5TEmnBa6/c0aYRdnRFaXv4CN7wcrdPF2ul2DVzN+Lzph6FxSrT83DZ/qV09PlM7o GyFOP2dQ7eUMTsr72ncVBQGlGplCVW5utxNqOeyhL8zntJP7oE/HOET+rrdPpCOiyf 3ZWI/9QExnUC7OQdhvMv4nUPe0bgP4nU9Pc8xQq3lWfLdEnBIb9FhuJg/3TniUtiRF JZVunGKr8zzwg7mnLvUXfYS8Tf6dXdJ5dUoCzIzr+iRjUlAxPeVIyzOvqgxDg0UFK0 3HySaAjtGi7TQRTCoCORlMONz9iN5pFryQBgTyr4rYCH8RHIeBjvtzGhfvaJymiGds eyqEe1l+agWyw== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhE-00000003kws-2TbJ; Wed, 27 Aug 2025 16:24:40 -0400 Message-ID: <20250827202440.444464744@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:50 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org Subject: [PATCH v10 02/11] unwind_user/sframe: Store sframe section data in per-mm maple tree References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf Associate an sframe section with its mm by adding it to a per-mm maple tree which is indexed by the corresponding text address range. A single sframe section can be associated with multiple text ranges. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Andrew Morton Cc: David Hildenbrand Cc: Lorenzo Stoakes Cc: "Liam R. Howlett" Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: x86@kernel.org Cc: linux-mm@kvack.org Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- arch/x86/include/asm/mmu.h | 2 +- include/linux/mm_types.h | 3 +++ include/linux/sframe.h | 13 +++++++++ kernel/fork.c | 10 +++++++ kernel/unwind/sframe.c | 55 +++++++++++++++++++++++++++++++++++--- mm/init-mm.c | 2 ++ 6 files changed, 81 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 0fe9c569d171..227a32899a59 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -87,7 +87,7 @@ typedef struct { .context =3D { \ .ctx_id =3D 1, \ .lock =3D __MUTEX_INITIALIZER(mm.context.lock), \ - } + }, =20 void leave_mm(void); #define leave_mm leave_mm diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 08bc2442db93..31fbd6663047 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1210,6 +1210,9 @@ struct mm_struct { #ifdef CONFIG_MM_ID mm_id_t mm_id; #endif /* CONFIG_MM_ID */ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + struct maple_tree sframe_mt; +#endif } __randomize_layout; =20 /* diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 0584f661f698..73bf6f0b30c2 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -22,18 +22,31 @@ struct sframe_section { signed char fp_off; }; =20 +#define INIT_MM_SFRAME .sframe_mt =3D MTREE_INIT(sframe_mt, 0), +extern void sframe_free_mm(struct mm_struct *mm); + extern int sframe_add_section(unsigned long sframe_start, unsigned long sf= rame_end, unsigned long text_start, unsigned long text_end); extern int sframe_remove_section(unsigned long sframe_addr); =20 +static inline bool current_has_sframe(void) +{ + struct mm_struct *mm =3D current->mm; + + return mm && !mtree_empty(&mm->sframe_mt); +} + #else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */ =20 +#define INIT_MM_SFRAME +static inline void sframe_free_mm(struct mm_struct *mm) {} static inline int sframe_add_section(unsigned long sframe_start, unsigned = long sframe_end, unsigned long text_start, unsigned long text_end) { return -ENOSYS; } static inline int sframe_remove_section(unsigned long sframe_addr) { retur= n -ENOSYS; } +static inline bool current_has_sframe(void) { return false; } =20 #endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */ =20 diff --git a/kernel/fork.c b/kernel/fork.c index af673856499d..496781b389bc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -106,6 +106,7 @@ #include #include #include +#include =20 #include #include @@ -690,6 +691,7 @@ void __mmdrop(struct mm_struct *mm) mm_destroy_cid(mm); percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS); futex_hash_free(mm); + sframe_free_mm(mm); =20 free_mm(mm); } @@ -1027,6 +1029,13 @@ static void mmap_init_lock(struct mm_struct *mm) #endif } =20 +static void mm_init_sframe(struct mm_struct *mm) +{ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + mt_init(&mm->sframe_mt); +#endif +} + static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct = *p, struct user_namespace *user_ns) { @@ -1055,6 +1064,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm= , struct task_struct *p, mm->pmd_huge_pte =3D NULL; #endif mm_init_uprobes_state(mm); + mm_init_sframe(mm); hugetlb_count_init(mm); =20 if (current->mm) { diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index 20287f795b36..fa7d87ffd00a 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -122,15 +122,64 @@ int sframe_add_section(unsigned long sframe_start, un= signed long sframe_end, if (ret) goto err_free; =20 - /* TODO nowhere to store it yet - just free it and return an error */ - ret =3D -ENOSYS; + ret =3D mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec= , GFP_KERNEL); + if (ret) { + dbg("mtree_insert_range failed: text=3D%lx-%lx\n", + sec->text_start, sec->text_end); + goto err_free; + } + + return 0; =20 err_free: free_section(sec); return ret; } =20 +static int __sframe_remove_section(struct mm_struct *mm, + struct sframe_section *sec) +{ + if (!mtree_erase(&mm->sframe_mt, sec->text_start)) { + dbg("mtree_erase failed: text=3D%lx\n", sec->text_start); + return -EINVAL; + } + + free_section(sec); + + return 0; +} + int sframe_remove_section(unsigned long sframe_start) { - return -ENOSYS; + struct mm_struct *mm =3D current->mm; + struct sframe_section *sec; + unsigned long index =3D 0; + bool found =3D false; + int ret =3D 0; + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) { + if (sec->sframe_start =3D=3D sframe_start) { + found =3D true; + ret |=3D __sframe_remove_section(mm, sec); + } + } + + if (!found || ret) + return -EINVAL; + + return 0; +} + +void sframe_free_mm(struct mm_struct *mm) +{ + struct sframe_section *sec; + unsigned long index =3D 0; + + if (!mm) + return; + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) + free_section(sec); + + mtree_destroy(&mm->sframe_mt); } diff --git a/mm/init-mm.c b/mm/init-mm.c index 4600e7605cab..b32fcf167cc2 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -11,6 +11,7 @@ #include #include #include +#include #include =20 #ifndef INIT_MM_CONTEXT @@ -46,6 +47,7 @@ struct mm_struct init_mm =3D { .user_ns =3D &init_user_ns, .cpu_bitmap =3D CPU_BITS_NONE, INIT_MM_CONTEXT(init_mm) + INIT_MM_SFRAME }; 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Wed, 27 Aug 2025 16:24:40 -0400 Message-ID: <20250827202440.610489845@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:51 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 03/11] x86/uaccess: Add unsafe_copy_from_user() implementation References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf Add an x86 implementation of unsafe_copy_from_user() similar to the existing unsafe_copy_to_user(). Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- arch/x86/include/asm/uaccess.h | 39 +++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 3a7755c1a441..3caf02d0503e 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -599,7 +599,7 @@ _label: \ * We want the unsafe accessors to always be inlined and use * the error labels - thus the macro games. */ -#define unsafe_copy_loop(dst, src, len, type, label) \ +#define unsafe_copy_to_user_loop(dst, src, len, type, label) \ while (len >=3D sizeof(type)) { \ unsafe_put_user(*(type *)(src),(type __user *)(dst),label); \ dst +=3D sizeof(type); \ @@ -607,15 +607,34 @@ _label: \ len -=3D sizeof(type); \ } =20 -#define unsafe_copy_to_user(_dst,_src,_len,label) \ -do { \ - char __user *__ucu_dst =3D (_dst); \ - const char *__ucu_src =3D (_src); \ - size_t __ucu_len =3D (_len); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ +#define unsafe_copy_to_user(_dst, _src, _len, label) \ +do { \ + void __user *__dst =3D (_dst); \ + const void *__src =3D (_src); \ + size_t __len =3D (_len); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u64, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u32, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u16, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u8, label); \ +} while (0) + +#define unsafe_copy_from_user_loop(dst, src, len, type, label) \ + while (len >=3D sizeof(type)) { \ + unsafe_get_user(*(type *)(dst), (type __user *)(src), label); \ + dst +=3D sizeof(type); \ + src +=3D sizeof(type); \ + len -=3D sizeof(type); \ + } + +#define unsafe_copy_from_user(_dst, _src, _len, label) \ +do { \ + void *__dst =3D (_dst); \ + void __user *__src =3D (_src); \ + size_t __len =3D (_len); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u64, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u32, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u16, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u8, label); \ } while (0) =20 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C94D2F0C62; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=CN45H9jF1zsdidSFE5bkvlncHxawBND28dlJA1hrZfOrZmmjWxcQArzaaqB+3UfP2Mzi7j0sHxA8r47GQWBWgx8wtGjGuiMI2kiEmbnw5aAbHJm5lSmQaIXE87MjcPs3v3bNkc9/magHDrBI3pSqPOZEZwS6hjPZ5vVqerV0cWY= ARC-Message-Signature: i=1; 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Wed, 27 Aug 2025 16:24:40 -0400 Message-ID: <20250827202440.778004183@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:52 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 04/11] unwind_user/sframe: Add support for reading .sframe contents References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf In preparation for using sframe to unwind user space stacks, add an sframe_find() interface for finding the sframe information associated with a given text address. For performance, use user_read_access_begin() and the corresponding unsafe_*() accessors. Note that use of pr_debug() in uaccess-enabled regions would break noinstr validation, so there aren't any debug messages yet. That will be added in a subsequent commit. Link: https://lore.kernel.org/all/77c0d1ec143bf2a53d66c4ecb190e7e0a576fbfd.= 1737511963.git.jpoimboe@kernel.org/ Link: https://lore.kernel.org/all/b35ca3a3-8de5-4d32-8d30-d4e562f6b0de@linu= x.ibm.com/ Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- include/linux/sframe.h | 5 + kernel/unwind/sframe.c | 311 ++++++++++++++++++++++++++++++++++- kernel/unwind/sframe_debug.h | 35 ++++ 3 files changed, 347 insertions(+), 4 deletions(-) create mode 100644 kernel/unwind/sframe_debug.h diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 73bf6f0b30c2..9a72209696f9 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -3,11 +3,14 @@ #define _LINUX_SFRAME_H =20 #include +#include #include =20 #ifdef CONFIG_HAVE_UNWIND_USER_SFRAME =20 struct sframe_section { + struct rcu_head rcu; + unsigned long sframe_start; unsigned long sframe_end; unsigned long text_start; @@ -28,6 +31,7 @@ extern void sframe_free_mm(struct mm_struct *mm); extern int sframe_add_section(unsigned long sframe_start, unsigned long sf= rame_end, unsigned long text_start, unsigned long text_end); extern int sframe_remove_section(unsigned long sframe_addr); +extern int sframe_find(unsigned long ip, struct unwind_user_frame *frame); =20 static inline bool current_has_sframe(void) { @@ -46,6 +50,7 @@ static inline int sframe_add_section(unsigned long sframe= _start, unsigned long s return -ENOSYS; } static inline int sframe_remove_section(unsigned long sframe_addr) { retur= n -ENOSYS; } +static inline int sframe_find(unsigned long ip, struct unwind_user_frame *= frame) { return -ENOSYS; } static inline bool current_has_sframe(void) { return false; } =20 #endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */ diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index fa7d87ffd00a..b10420d19840 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -15,9 +15,303 @@ #include =20 #include "sframe.h" +#include "sframe_debug.h" =20 -#define dbg(fmt, ...) \ - pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) +struct sframe_fre { + unsigned int size; + u32 ip_off; + s32 cfa_off; + s32 ra_off; + s32 fp_off; + u8 info; +}; + +DEFINE_STATIC_SRCU(sframe_srcu); + +static __always_inline unsigned char fre_type_to_size(unsigned char fre_ty= pe) +{ + if (fre_type > 2) + return 0; + return 1 << fre_type; +} + +static __always_inline unsigned char offset_size_enum_to_size(unsigned cha= r off_size) +{ + if (off_size > 2) + return 0; + return 1 << off_size; +} + +static __always_inline int __read_fde(struct sframe_section *sec, + unsigned int fde_num, + struct sframe_fde *fde) +{ + unsigned long fde_addr, ip; + + fde_addr =3D sec->fdes_start + (fde_num * sizeof(struct sframe_fde)); + unsafe_copy_from_user(fde, (void __user *)fde_addr, + sizeof(struct sframe_fde), Efault); + + ip =3D sec->sframe_start + fde->start_addr; + if (ip < sec->text_start || ip > sec->text_end) + return -EINVAL; + + return 0; + +Efault: + return -EFAULT; +} + +static __always_inline int __find_fde(struct sframe_section *sec, + unsigned long ip, + struct sframe_fde *fde) +{ + s32 ip_off, func_off_low =3D S32_MIN, func_off_high =3D S32_MAX; + struct sframe_fde __user *first, *low, *high, *found =3D NULL; + int ret; + + ip_off =3D ip - sec->sframe_start; + + first =3D (void __user *)sec->fdes_start; + low =3D first; + high =3D first + sec->num_fdes - 1; + + while (low <=3D high) { + struct sframe_fde __user *mid; + s32 func_off; + + mid =3D low + ((high - low) / 2); + + unsafe_get_user(func_off, (s32 __user *)mid, Efault); + + if (ip_off >=3D func_off) { + if (func_off < func_off_low) + return -EFAULT; + + func_off_low =3D func_off; + + found =3D mid; + low =3D mid + 1; + } else { + if (func_off > func_off_high) + return -EFAULT; + + func_off_high =3D func_off; + + high =3D mid - 1; + } + } + + if (!found) + return -EINVAL; + + ret =3D __read_fde(sec, found - first, fde); + if (ret) + return ret; + + /* make sure it's not in a gap */ + if (ip_off < fde->start_addr || ip_off >=3D fde->start_addr + fde->func_s= ize) + return -EINVAL; + + return 0; + +Efault: + return -EFAULT; +} + +#define ____UNSAFE_GET_USER_INC(to, from, type, label) \ +({ \ + type __to; \ + unsafe_get_user(__to, (type __user *)from, label); \ + from +=3D sizeof(__to); \ + to =3D __to; \ +}) + +#define __UNSAFE_GET_USER_INC(to, from, size, label, u_or_s) \ +({ \ + switch (size) { \ + case 1: \ + ____UNSAFE_GET_USER_INC(to, from, u_or_s##8, label); \ + break; \ + case 2: \ + ____UNSAFE_GET_USER_INC(to, from, u_or_s##16, label); \ + break; \ + case 4: \ + ____UNSAFE_GET_USER_INC(to, from, u_or_s##32, label); \ + break; \ + default: \ + return -EFAULT; \ + } \ +}) + +#define UNSAFE_GET_USER_UNSIGNED_INC(to, from, size, label) \ + __UNSAFE_GET_USER_INC(to, from, size, label, u) + +#define UNSAFE_GET_USER_SIGNED_INC(to, from, size, label) \ + __UNSAFE_GET_USER_INC(to, from, size, label, s) + +#define UNSAFE_GET_USER_INC(to, from, size, label) \ + _Generic(to, \ + u8: UNSAFE_GET_USER_UNSIGNED_INC(to, from, size, label), \ + u16: UNSAFE_GET_USER_UNSIGNED_INC(to, from, size, label), \ + u32: UNSAFE_GET_USER_UNSIGNED_INC(to, from, size, label), \ + s8: UNSAFE_GET_USER_SIGNED_INC(to, from, size, label), \ + s16: UNSAFE_GET_USER_SIGNED_INC(to, from, size, label), \ + s32: UNSAFE_GET_USER_SIGNED_INC(to, from, size, label)) + +static __always_inline int __read_fre(struct sframe_section *sec, + struct sframe_fde *fde, + unsigned long fre_addr, + struct sframe_fre *fre) +{ + unsigned char fde_type =3D SFRAME_FUNC_FDE_TYPE(fde->info); + unsigned char fre_type =3D SFRAME_FUNC_FRE_TYPE(fde->info); + unsigned char offset_count, offset_size; + s32 cfa_off, ra_off, fp_off; + unsigned long cur =3D fre_addr; + unsigned char addr_size; + u32 ip_off; + u8 info; + + addr_size =3D fre_type_to_size(fre_type); + if (!addr_size) + return -EFAULT; + + if (fre_addr + addr_size + 1 > sec->fres_end) + return -EFAULT; + + UNSAFE_GET_USER_INC(ip_off, cur, addr_size, Efault); + if (fde_type =3D=3D SFRAME_FDE_TYPE_PCINC && ip_off > fde->func_size) + return -EFAULT; + + UNSAFE_GET_USER_INC(info, cur, 1, Efault); + offset_count =3D SFRAME_FRE_OFFSET_COUNT(info); + offset_size =3D offset_size_enum_to_size(SFRAME_FRE_OFFSET_SIZE(info)); + if (!offset_count || !offset_size) + return -EFAULT; + + if (cur + (offset_count * offset_size) > sec->fres_end) + return -EFAULT; + + fre->size =3D addr_size + 1 + (offset_count * offset_size); + + UNSAFE_GET_USER_INC(cfa_off, cur, offset_size, Efault); + offset_count--; + + ra_off =3D sec->ra_off; + if (!ra_off) { + if (!offset_count--) + return -EFAULT; + + UNSAFE_GET_USER_INC(ra_off, cur, offset_size, Efault); + } + + fp_off =3D sec->fp_off; + if (!fp_off && offset_count) { + offset_count--; + UNSAFE_GET_USER_INC(fp_off, cur, offset_size, Efault); + } + + if (offset_count) + return -EFAULT; + + fre->ip_off =3D ip_off; + fre->cfa_off =3D cfa_off; + fre->ra_off =3D ra_off; + fre->fp_off =3D fp_off; + fre->info =3D info; + + return 0; + +Efault: + return -EFAULT; +} + +static __always_inline int __find_fre(struct sframe_section *sec, + struct sframe_fde *fde, unsigned long ip, + struct unwind_user_frame *frame) +{ + unsigned char fde_type =3D SFRAME_FUNC_FDE_TYPE(fde->info); + struct sframe_fre *fre, *prev_fre =3D NULL; + struct sframe_fre fres[2]; + unsigned long fre_addr; + bool which =3D false; + unsigned int i; + u32 ip_off; + + ip_off =3D ip - (sec->sframe_start + fde->start_addr); + + if (fde_type =3D=3D SFRAME_FDE_TYPE_PCMASK) + ip_off %=3D fde->rep_size; + + fre_addr =3D sec->fres_start + fde->fres_off; + + for (i =3D 0; i < fde->fres_num; i++) { + int ret; + + /* + * Alternate between the two fre_addr[] entries for 'fre' and + * 'prev_fre'. + */ + fre =3D which ? fres : fres + 1; + which =3D !which; + + ret =3D __read_fre(sec, fde, fre_addr, fre); + if (ret) + return ret; + + fre_addr +=3D fre->size; + + if (prev_fre && fre->ip_off <=3D prev_fre->ip_off) + return -EFAULT; + + if (fre->ip_off > ip_off) + break; + + prev_fre =3D fre; + } + + if (!prev_fre) + return -EINVAL; + fre =3D prev_fre; + + frame->cfa_off =3D fre->cfa_off; + frame->ra_off =3D fre->ra_off; + frame->fp_off =3D fre->fp_off; + frame->use_fp =3D SFRAME_FRE_CFA_BASE_REG_ID(fre->info) =3D=3D SFRAME_BA= SE_REG_FP; + + return 0; +} + +int sframe_find(unsigned long ip, struct unwind_user_frame *frame) +{ + struct mm_struct *mm =3D current->mm; + struct sframe_section *sec; + struct sframe_fde fde; + int ret; + + if (!mm) + return -EINVAL; + + guard(srcu)(&sframe_srcu); + + sec =3D mtree_load(&mm->sframe_mt, ip); + if (!sec) + return -EINVAL; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + + ret =3D __find_fde(sec, ip, &fde); + if (ret) + goto end; + + ret =3D __find_fre(sec, &fde, ip, frame); +end: + user_read_access_end(); + return ret; +} =20 static void free_section(struct sframe_section *sec) { @@ -119,8 +413,10 @@ int sframe_add_section(unsigned long sframe_start, uns= igned long sframe_end, sec->text_end =3D text_end; =20 ret =3D sframe_read_header(sec); - if (ret) + if (ret) { + dbg_print_header(sec); goto err_free; + } =20 ret =3D mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec= , GFP_KERNEL); if (ret) { @@ -136,6 +432,13 @@ int sframe_add_section(unsigned long sframe_start, uns= igned long sframe_end, return ret; } =20 +static void sframe_free_srcu(struct rcu_head *rcu) +{ + struct sframe_section *sec =3D container_of(rcu, struct sframe_section, r= cu); + + free_section(sec); +} + static int __sframe_remove_section(struct mm_struct *mm, struct sframe_section *sec) { @@ -144,7 +447,7 @@ static int __sframe_remove_section(struct mm_struct *mm, return -EINVAL; } =20 - free_section(sec); + call_srcu(&sframe_srcu, &sec->rcu, sframe_free_srcu); =20 return 0; } diff --git a/kernel/unwind/sframe_debug.h b/kernel/unwind/sframe_debug.h new file mode 100644 index 000000000000..055c8c8fae24 --- /dev/null +++ b/kernel/unwind/sframe_debug.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _SFRAME_DEBUG_H +#define _SFRAME_DEBUG_H + +#include +#include "sframe.h" + +#ifdef CONFIG_DYNAMIC_DEBUG + +#define dbg(fmt, ...) \ + pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) + +static __always_inline void dbg_print_header(struct sframe_section *sec) +{ + unsigned long fdes_end; + + fdes_end =3D sec->fdes_start + (sec->num_fdes * sizeof(struct sframe_fde)= ); + + dbg("SEC: sframe:0x%lx-0x%lx text:0x%lx-0x%lx " + "fdes:0x%lx-0x%lx fres:0x%lx-0x%lx " + "ra_off:%d fp_off:%d\n", + sec->sframe_start, sec->sframe_end, sec->text_start, sec->text_end, + sec->fdes_start, fdes_end, sec->fres_start, sec->fres_end, + sec->ra_off, sec->fp_off); +} + +#else /* !CONFIG_DYNAMIC_DEBUG */ + +#define dbg(args...) no_printk(args) + +static inline void dbg_print_header(struct sframe_section *sec) {} + +#endif /* !CONFIG_DYNAMIC_DEBUG */ + +#endif /* _SFRAME_DEBUG_H */ --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FDE72FD7CE; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=MlJr0OyGh/Lt7kMmq1cES2iipoRTl25+zm3rn30kXi6KpCr8W2LyChVgGbGzDsyMV240n8q4nucDzCIp6SiYipLksv8Us8JtOMGX7pQ83cxnBZr6kWdwJ3t2Agxq5493GndGWdKo4Nf1hHM9zLzJZx47ccT5P4RxZWSWnO5wD7E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; 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Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202440.946751792@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:53 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" , linux-mm@kvack.org Subject: [PATCH v10 05/11] unwind_user/sframe: Detect .sframe sections in executables References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf When loading an ELF executable, automatically detect an .sframe section and associate it with the mm_struct. Cc: linux-mm@kvack.org Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- fs/binfmt_elf.c | 49 +++++++++++++++++++++++++++++++++++++--- include/uapi/linux/elf.h | 1 + 2 files changed, 47 insertions(+), 3 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 264fba0d44bd..1fd7623cf9a5 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include =20 @@ -622,6 +623,21 @@ static inline int make_prot(u32 p_flags, struct arch_e= lf_state *arch_state, return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp); } =20 +static void elf_add_sframe(struct elf_phdr *text, struct elf_phdr *sframe, + unsigned long base_addr) +{ + unsigned long sframe_start, sframe_end, text_start, text_end; + + sframe_start =3D base_addr + sframe->p_vaddr; + sframe_end =3D sframe_start + sframe->p_memsz; + + text_start =3D base_addr + text->p_vaddr; + text_end =3D text_start + text->p_memsz; + + /* Ignore return value, sframe section isn't critical */ + sframe_add_section(sframe_start, sframe_end, text_start, text_end); +} + /* This is much more generalized than the library routine read function, so we keep this separate. Technically the library read function is only provided so that we can read a.out libraries that have @@ -632,7 +648,7 @@ static unsigned long load_elf_interp(struct elfhdr *int= erp_elf_ex, unsigned long no_base, struct elf_phdr *interp_elf_phdata, struct arch_elf_state *arch_state) { - struct elf_phdr *eppnt; + struct elf_phdr *eppnt, *sframe_phdr =3D NULL; unsigned long load_addr =3D 0; int load_addr_set =3D 0; unsigned long error =3D ~0UL; @@ -658,7 +674,8 @@ static unsigned long load_elf_interp(struct elfhdr *int= erp_elf_ex, =20 eppnt =3D interp_elf_phdata; for (i =3D 0; i < interp_elf_ex->e_phnum; i++, eppnt++) { - if (eppnt->p_type =3D=3D PT_LOAD) { + switch (eppnt->p_type) { + case PT_LOAD: { int elf_type =3D MAP_PRIVATE; int elf_prot =3D make_prot(eppnt->p_flags, arch_state, true, true); @@ -697,6 +714,20 @@ static unsigned long load_elf_interp(struct elfhdr *in= terp_elf_ex, error =3D -ENOMEM; goto out; } + break; + } + case PT_GNU_SFRAME: + sframe_phdr =3D eppnt; + break; + } + } + + if (sframe_phdr) { + eppnt =3D interp_elf_phdata; + for (i =3D 0; i < interp_elf_ex->e_phnum; i++, eppnt++) { + if (eppnt->p_flags & PF_X) { + elf_add_sframe(eppnt, sframe_phdr, load_addr); + } } } =20 @@ -821,7 +852,7 @@ static int load_elf_binary(struct linux_binprm *bprm) int first_pt_load =3D 1; unsigned long error; struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata =3D NULL; - struct elf_phdr *elf_property_phdata =3D NULL; + struct elf_phdr *elf_property_phdata =3D NULL, *sframe_phdr =3D NULL; unsigned long elf_brk; bool brk_moved =3D false; int retval, i; @@ -930,6 +961,10 @@ static int load_elf_binary(struct linux_binprm *bprm) executable_stack =3D EXSTACK_DISABLE_X; break; =20 + case PT_GNU_SFRAME: + sframe_phdr =3D elf_ppnt; + break; + case PT_LOPROC ... PT_HIPROC: retval =3D arch_elf_pt_proc(elf_ex, elf_ppnt, bprm->file, false, @@ -1227,6 +1262,14 @@ static int load_elf_binary(struct linux_binprm *bprm) elf_brk =3D k; } =20 + if (sframe_phdr) { + for (i =3D 0, elf_ppnt =3D elf_phdata; + i < elf_ex->e_phnum; i++, elf_ppnt++) { + if ((elf_ppnt->p_flags & PF_X)) + elf_add_sframe(elf_ppnt, sframe_phdr, load_bias); + } + } + e_entry =3D elf_ex->e_entry + load_bias; phdr_addr +=3D load_bias; elf_brk +=3D load_bias; diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 819ded2d39de..92c16c94fca8 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -41,6 +41,7 @@ typedef __u16 Elf64_Versym; #define PT_GNU_STACK (PT_LOOS + 0x474e551) #define PT_GNU_RELRO (PT_LOOS + 0x474e552) #define PT_GNU_PROPERTY (PT_LOOS + 0x474e553) +#define PT_GNU_SFRAME (PT_LOOS + 0x474e554) =20 =20 /* ARM MTE memory tag segment type */ --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA78C3009F8; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=fPnj56giJNARcXvfZquMdqr20vcnWmgk9stw0VTSI2jJoJ9V6tnz4q38ukzqokvJd0W9Q9QvaYVh8+dReCj0CiBzgxn4NMTDMyhnnT1bFEdQjVo8I5bhWVCa5Iu/orMFpdbCr4lKFARktgCr/w/yWUDX2gs+bYbXThfX9BwFkDw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; c=relaxed/simple; bh=vircrvv7Zq8GxATMbia1gUCQK1TDM+Rw9iJ5FVuaMNc=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ICLclZtTx5QHSplsJ+axJHRBH6WGuyp6qeBM9yQf3lBs8MS7st6f990vlfwSrLaNQK1V7LjUheDHm4VKDsaIvzM8bfY9enESZ5fIXEU69aQnfdBjxyLy+z2W9NAaj+kBZGOTHy6ZsEV4jsAWE/DMNsW9zTTRKr2lv3GT5rKwD4Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hXf2X4nI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hXf2X4nI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5978EC116C6; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326262; bh=vircrvv7Zq8GxATMbia1gUCQK1TDM+Rw9iJ5FVuaMNc=; h=Date:From:To:Cc:Subject:References:From; b=hXf2X4nI3wC4VendwY6X1JKrPGLSBB1jukfIHjsjm9Z1r4Yy+IB1srFg/yMjjzTfJ 17u4cLmAijsGKbk1iWpVcwtfpoLm4YXitZWYS2Um1EpJ8RLDCnKqQ2unr4f/lS+DYW Xyc2tzRML81yHvkKHyIcFHcKTtdg3fENSV9fqL/yBEPcGo/qtfBlkFAxcnCeW+Ja7V TyFTkMMCYoKkpBzpo/KoOPzF/yGx6a6OT1zfk/nGrQ5Qt386eEzDASjUQ0QvtnoPH9 gTCZQcXJ13J8wG/iSc5T7/FjTx3Fig5BIyLPwlCLsRB8F2As1+2/7M2t705A5R/Cp4 uEv44BvW0pJ+g== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhF-00000003kyp-1576; Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.115677905@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:54 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 06/11] unwind_user/sframe: Wire up unwind_user to sframe References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf Now that the sframe infrastructure is fully in place, make it work by hooking it up to the unwind_user interface. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- Changes since v9: https://lore.kernel.org/20250717012936.619600891@kernel.o= rg - Update the changes to unwind/user.c to handle passing a const unwind_user_frame pointer. arch/Kconfig | 1 + include/linux/unwind_user_types.h | 4 ++- kernel/unwind/user.c | 41 +++++++++++++++++++++++++++++-- 3 files changed, 43 insertions(+), 3 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 69fcabf53088..277b87af949f 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -453,6 +453,7 @@ config HAVE_UNWIND_USER_FP =20 config HAVE_UNWIND_USER_SFRAME bool + select UNWIND_USER =20 config HAVE_PERF_REGS bool diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_= types.h index a449f15be890..d30e8495eaa9 100644 --- a/include/linux/unwind_user_types.h +++ b/include/linux/unwind_user_types.h @@ -9,7 +9,8 @@ * available. */ enum unwind_user_type_bits { - UNWIND_USER_TYPE_FP_BIT =3D 0, + UNWIND_USER_TYPE_SFRAME_BIT =3D 0, + UNWIND_USER_TYPE_FP_BIT =3D 1, =20 NR_UNWIND_USER_TYPE_BITS, }; @@ -17,6 +18,7 @@ enum unwind_user_type_bits { enum unwind_user_type { /* Type "none" for the start of stack walk iteration. */ UNWIND_USER_TYPE_NONE =3D 0, + UNWIND_USER_TYPE_SFRAME =3D BIT(UNWIND_USER_TYPE_SFRAME_BIT), UNWIND_USER_TYPE_FP =3D BIT(UNWIND_USER_TYPE_FP_BIT), }; =20 diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c index 97a8415e3216..9d34c7659f90 100644 --- a/kernel/unwind/user.c +++ b/kernel/unwind/user.c @@ -7,17 +7,24 @@ #include #include #include +#include =20 static const struct unwind_user_frame fp_frame =3D { ARCH_INIT_USER_FP_FRAME }; =20 +static const struct unwind_user_frame *get_fp_frame(struct pt_regs *regs) +{ + return &fp_frame; +} + #define for_each_user_frame(state) \ for (unwind_user_start(state); !(state)->done; unwind_user_next(state)) =20 -static int unwind_user_next_fp(struct unwind_user_state *state) +static int unwind_user_next_common(struct unwind_user_state *state, + const struct unwind_user_frame *frame, + struct pt_regs *regs) { - const struct unwind_user_frame *frame =3D &fp_frame; unsigned long cfa, fp, ra; unsigned int shift; =20 @@ -55,6 +62,24 @@ static int unwind_user_next_fp(struct unwind_user_state = *state) return 0; } =20 +static int unwind_user_next_sframe(struct unwind_user_state *state) +{ + struct unwind_user_frame _frame, *frame; + + /* sframe expects the frame to be local storage */ + frame =3D &_frame; + if (sframe_find(state->ip, frame)) + return -ENOENT; + return unwind_user_next_common(state, frame, task_pt_regs(current)); +} + +static int unwind_user_next_fp(struct unwind_user_state *state) +{ + struct pt_regs *regs =3D task_pt_regs(current); + + return unwind_user_next_common(state, get_fp_frame(regs), regs); +} + static int unwind_user_next(struct unwind_user_state *state) { unsigned long iter_mask =3D state->available_types; @@ -68,6 +93,16 @@ static int unwind_user_next(struct unwind_user_state *st= ate) =20 state->current_type =3D type; switch (type) { + case UNWIND_USER_TYPE_SFRAME: + switch (unwind_user_next_sframe(state)) { + case 0: + return 0; + case -ENOENT: + continue; /* Try next method. */ + default: + state->done =3D true; + } + break; case UNWIND_USER_TYPE_FP: if (!unwind_user_next_fp(state)) return 0; @@ -96,6 +131,8 @@ static int unwind_user_start(struct unwind_user_state *s= tate) return -EINVAL; } =20 + if (current_has_sframe()) + state->available_types |=3D UNWIND_USER_TYPE_SFRAME; if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP)) state->available_types |=3D UNWIND_USER_TYPE_FP; =20 --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A23042FFDE6; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=lwfyMSPUAc25+6pN7hoawDVz4fIatqxK5U0cSIkz9ogev3C9SIai0gJstxNSzxsPeLz6bNfGGLZbFVsl95G0mlmzvdMsl4g3Af0hcLXna1NsTs6vE/8voDhEH3rjXPZM6f++fxK7jJwJsCE5ywEQlKZgN+wd0eUOmfacRBD1Xps= ARC-Message-Signature: i=1; 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Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.276817748@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:55 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 07/11] unwind_user/sframe/x86: Enable sframe unwinding on x86 References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf The x86 sframe 2.0 implementation works fairly well, starting with binutils 2.41 (though some bugs are getting fixed in later versions). Enable it. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 8f94c58d4de8..c3518f145f0d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -300,6 +300,7 @@ config X86 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_UNWIND_USER_FP if X86_64 + select HAVE_UNWIND_USER_SFRAME if X86_64 select HAVE_USER_RETURN_NOTIFIER select HAVE_GENERIC_VDSO select VDSO_GETRANDOM if X86_64 --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D06F2301028; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; cv=none; b=lNM30zzYZDfC2vqphWaraRVjiJWLGukz9XvcFsxNHVi62M8Wb/scGXdPoqgQ/ExhYM9XvkkudeQe06A4mFhEI8QRD02EeOXVrV/Y2ovq6Euyaiqi3k5UU9fPBWAMu/pkhaLK5xc8+1WJbRa7JXTBrOlY4yW0ZQZdRg3PcdPlEkA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326262; c=relaxed/simple; bh=EgHoeoxXCjxslVJujBtFAK4/oaW+ZtT15/3T3C1cFpY=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=BJYbPQuy71AdQTVsO60B5fXxkw/IEXT8m60sQLymKbNE0TJX3pJ1YPkTxlxkgnRvYY4lrBl8xBmCHHgJoOcMGREYM+WgTFgIhebIbvA7z1sTyS+6r8BdF9uZGdkjCDHtWDgD0dSfYTufZyQJOnbeOIH5ccRA94osQtIKFZwCSg0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=APHVpDv6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="APHVpDv6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABA31C4CEFA; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326262; bh=EgHoeoxXCjxslVJujBtFAK4/oaW+ZtT15/3T3C1cFpY=; h=Date:From:To:Cc:Subject:References:From; b=APHVpDv6+sGOzsT07FlPoOJMlel/ovN020dbdkghGgEQBAOAaCqSix3fFPp1/NI/Y nBovlfX2dNP7yv4p6DMvSRceP0s4TpUi9poQA2YduXYwGrTGTbqCeRaDyCd9ax89tz S/4wjyxoeI1aXmiV7d9mEIXxxZ8sOIaHfO8RV4Wr2z+8PerpXU2DbjM+SGeecsFNIM ag4eQBqAm+RGCtjWyg5Z8q+SoH3vcP4NnVWKAgijHnW/j+n8gAzm9Z0c7mey6TvVRT 5UIRdimAi1TZND47cppFNcFAGcyAvcxbmnDxotDn4yg48VXlJMQ9ktVkYwwAq0WOTt Wva4yZzCMlfuw== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhF-00000003kzp-2Tcm; Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.441080427@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:56 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 08/11] unwind_user/sframe: Remove .sframe section on detected corruption References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf To avoid continued attempted use of a bad .sframe section, remove it on demand when the first sign of corruption is detected. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- kernel/unwind/sframe.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index b10420d19840..f246ead6c2a0 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -310,6 +310,10 @@ int sframe_find(unsigned long ip, struct unwind_user_f= rame *frame) ret =3D __find_fre(sec, &fde, ip, frame); end: user_read_access_end(); + + if (ret =3D=3D -EFAULT) + WARN_ON_ONCE(sframe_remove_section(sec->sframe_start)); + return ret; } =20 --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0750302767; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; cv=none; b=aHutAAOK4x0c+hu3F1kl5QC/qrE+QPdIs0tAiVA1NPvSy26CLj2Yg7cBHHR3k3/cCXX4SNW10IpuCtLbZpk0xZLzTnVBd3zgpLt3rh8zz4hcYPI6Vp4J98GxW6OpDkn1mT5zmOpIvh01zBqKJyqZtvyb+FIZopXdO42Ey19zfGM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; c=relaxed/simple; bh=+aOOqq5ATDlTuAY4Uj5/HzrzIr46HmGDaIoU2I/Lquk=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=giozKj3CrZV/AhYF/+i+ZY00mjE3vY2aGK+EaBvmTtMgfheAGHIlOSs0RGLgTdRzXx8b65lkAsQVKt+IPkr1z3SOH5sfqvemiMBaJ1HGJwdQ2kPRDoQkBFCh9CLtDHVro2vmVumjDfv7s3zHu0NEanHKSVGipg0LszyCZDJ/puU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nLxW+Cnf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nLxW+Cnf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA64DC4CEF7; Wed, 27 Aug 2025 20:24:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326262; bh=+aOOqq5ATDlTuAY4Uj5/HzrzIr46HmGDaIoU2I/Lquk=; h=Date:From:To:Cc:Subject:References:From; b=nLxW+CnfQiy3X6BsFI7f0ExL5YrD99XGL5GxmIW4hjwm7zgWzzEyO8DB9ysGUMCPc pEKejeI8FcPH68IgAQ0cISTewKN2+cpppEA3fi8IjgM5YnJtb5klFftKuwBdlLfrkN rn5aLZwR/hEx2RLo8OTmx/z9HVHddb++rZgTlrHoF3BbUl9Z/KyvqoeRunugjVVfJ5 +i6LXQrWjIVlzPWRq0tabozrZuYPIrF9hdL5uB/vqpA2DersfXKdymf3sIF1dWDt6D aJu3hX17i1YwCm/eg9r3td1l3AjWCCuVPpAZ9yk9NJygy1SSTiiHGxe6qiTvxDaEjo N1Y4tUCcvLNQg== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhF-00000003l0J-3AiB; Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.612134888@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:57 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 09/11] unwind_user/sframe: Show file name in debug output References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf When debugging sframe issues, the error messages aren't all that helpful without knowing what file a corresponding .sframe section belongs to. Prefix debug output strings with the file name. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- include/linux/sframe.h | 4 +++- kernel/unwind/sframe.c | 23 ++++++++++-------- kernel/unwind/sframe_debug.h | 45 +++++++++++++++++++++++++++++++----- 3 files changed, 56 insertions(+), 16 deletions(-) diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 9a72209696f9..b79c5ec09229 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -10,7 +10,9 @@ =20 struct sframe_section { struct rcu_head rcu; - +#ifdef CONFIG_DYNAMIC_DEBUG + const char *filename; +#endif unsigned long sframe_start; unsigned long sframe_end; unsigned long text_start; diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index f246ead6c2a0..66d3ba3c8389 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -311,14 +311,17 @@ int sframe_find(unsigned long ip, struct unwind_user_= frame *frame) end: user_read_access_end(); =20 - if (ret =3D=3D -EFAULT) + if (ret =3D=3D -EFAULT) { + dbg_sec("removing bad .sframe section\n"); WARN_ON_ONCE(sframe_remove_section(sec->sframe_start)); + } =20 return ret; } =20 static void free_section(struct sframe_section *sec) { + dbg_free(sec); kfree(sec); } =20 @@ -329,7 +332,7 @@ static int sframe_read_header(struct sframe_section *se= c) unsigned int num_fdes; =20 if (copy_from_user(&shdr, (void __user *)sec->sframe_start, sizeof(shdr))= ) { - dbg("header usercopy failed\n"); + dbg_sec("header usercopy failed\n"); return -EFAULT; } =20 @@ -337,18 +340,18 @@ static int sframe_read_header(struct sframe_section *= sec) shdr.preamble.version !=3D SFRAME_VERSION_2 || !(shdr.preamble.flags & SFRAME_F_FDE_SORTED) || shdr.auxhdr_len) { - dbg("bad/unsupported sframe header\n"); + dbg_sec("bad/unsupported sframe header\n"); return -EINVAL; } =20 if (!shdr.num_fdes || !shdr.num_fres) { - dbg("no fde/fre entries\n"); + dbg_sec("no fde/fre entries\n"); return -EINVAL; } =20 header_end =3D sec->sframe_start + SFRAME_HEADER_SIZE(shdr); if (header_end >=3D sec->sframe_end) { - dbg("header doesn't fit in section\n"); + dbg_sec("header doesn't fit in section\n"); return -EINVAL; } =20 @@ -360,7 +363,7 @@ static int sframe_read_header(struct sframe_section *se= c) fres_end =3D fres_start + shdr.fre_len; =20 if (fres_start < fdes_end || fres_end > sec->sframe_end) { - dbg("inconsistent fde/fre offsets\n"); + dbg_sec("inconsistent fde/fre offsets\n"); return -EINVAL; } =20 @@ -416,6 +419,8 @@ int sframe_add_section(unsigned long sframe_start, unsi= gned long sframe_end, sec->text_start =3D text_start; sec->text_end =3D text_end; =20 + dbg_init(sec); + ret =3D sframe_read_header(sec); if (ret) { dbg_print_header(sec); @@ -424,8 +429,8 @@ int sframe_add_section(unsigned long sframe_start, unsi= gned long sframe_end, =20 ret =3D mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec= , GFP_KERNEL); if (ret) { - dbg("mtree_insert_range failed: text=3D%lx-%lx\n", - sec->text_start, sec->text_end); + dbg_sec("mtree_insert_range failed: text=3D%lx-%lx\n", + sec->text_start, sec->text_end); goto err_free; } =20 @@ -447,7 +452,7 @@ static int __sframe_remove_section(struct mm_struct *mm, struct sframe_section *sec) { if (!mtree_erase(&mm->sframe_mt, sec->text_start)) { - dbg("mtree_erase failed: text=3D%lx\n", sec->text_start); + dbg_sec("mtree_erase failed: text=3D%lx\n", sec->text_start); return -EINVAL; } =20 diff --git a/kernel/unwind/sframe_debug.h b/kernel/unwind/sframe_debug.h index 055c8c8fae24..7794bf0bd78c 100644 --- a/kernel/unwind/sframe_debug.h +++ b/kernel/unwind/sframe_debug.h @@ -10,26 +10,59 @@ #define dbg(fmt, ...) \ pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) =20 +#define dbg_sec(fmt, ...) \ + dbg("%s: " fmt, sec->filename, ##__VA_ARGS__) + static __always_inline void dbg_print_header(struct sframe_section *sec) { unsigned long fdes_end; =20 fdes_end =3D sec->fdes_start + (sec->num_fdes * sizeof(struct sframe_fde)= ); =20 - dbg("SEC: sframe:0x%lx-0x%lx text:0x%lx-0x%lx " - "fdes:0x%lx-0x%lx fres:0x%lx-0x%lx " - "ra_off:%d fp_off:%d\n", - sec->sframe_start, sec->sframe_end, sec->text_start, sec->text_end, - sec->fdes_start, fdes_end, sec->fres_start, sec->fres_end, - sec->ra_off, sec->fp_off); + dbg_sec("SEC: sframe:0x%lx-0x%lx text:0x%lx-0x%lx " + "fdes:0x%lx-0x%lx fres:0x%lx-0x%lx " + "ra_off:%d fp_off:%d\n", + sec->sframe_start, sec->sframe_end, sec->text_start, sec->text_end, + sec->fdes_start, fdes_end, sec->fres_start, sec->fres_end, + sec->ra_off, sec->fp_off); +} + +static inline void dbg_init(struct sframe_section *sec) +{ + struct mm_struct *mm =3D current->mm; + struct vm_area_struct *vma; + + guard(mmap_read_lock)(mm); + vma =3D vma_lookup(mm, sec->sframe_start); + if (!vma) + sec->filename =3D kstrdup("(vma gone???)", GFP_KERNEL); + else if (vma->vm_file) + sec->filename =3D kstrdup_quotable_file(vma->vm_file, GFP_KERNEL); + else if (vma->vm_ops && vma->vm_ops->name) + sec->filename =3D kstrdup(vma->vm_ops->name(vma), GFP_KERNEL); + else if (arch_vma_name(vma)) + sec->filename =3D kstrdup(arch_vma_name(vma), GFP_KERNEL); + else if (!vma->vm_mm) + sec->filename =3D kstrdup("(vdso)", GFP_KERNEL); + else + sec->filename =3D kstrdup("(anonymous)", GFP_KERNEL); +} + +static inline void dbg_free(struct sframe_section *sec) +{ + kfree(sec->filename); 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Wed, 27 Aug 2025 16:24:41 -0400 Message-ID: <20250827202441.776912299@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:58 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 10/11] unwind_user/sframe: Add .sframe validation option References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf Add a debug feature to validate all .sframe sections when first loading the file rather than on demand. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- arch/Kconfig | 19 +++++++++ kernel/unwind/sframe.c | 96 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 115 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 277b87af949f..918ebe3c5a85 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -455,6 +455,25 @@ config HAVE_UNWIND_USER_SFRAME bool select UNWIND_USER =20 +config SFRAME_VALIDATION + bool "Enable .sframe section debugging" + depends on HAVE_UNWIND_USER_SFRAME + depends on DYNAMIC_DEBUG + help + When adding an .sframe section for a task, validate the entire + section immediately rather than on demand. + + This is a debug feature which is helpful for rooting out .sframe + section issues. If the .sframe section is corrupt, it will fail to + load immediately, with more information provided in dynamic printks. + + This has a significant page cache footprint due to its reading of the + entire .sframe section for every loaded executable and shared + library. Also, it's done for all processes, even those which don't + get stack traced by the kernel. Not recommended for general use. + + If unsure, say N. + config HAVE_PERF_REGS bool help diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index 66d3ba3c8389..79ff3c0fc11f 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -319,6 +319,98 @@ int sframe_find(unsigned long ip, struct unwind_user_f= rame *frame) return ret; } =20 +#ifdef CONFIG_SFRAME_VALIDATION + +static int safe_read_fde(struct sframe_section *sec, + unsigned int fde_num, struct sframe_fde *fde) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret =3D __read_fde(sec, fde_num, fde); + user_read_access_end(); + return ret; +} + +static int safe_read_fre(struct sframe_section *sec, + struct sframe_fde *fde, unsigned long fre_addr, + struct sframe_fre *fre) +{ + int ret; + + if (!user_read_access_begin((void __user *)sec->sframe_start, + sec->sframe_end - sec->sframe_start)) + return -EFAULT; + ret =3D __read_fre(sec, fde, fre_addr, fre); + user_read_access_end(); + return ret; +} + +static int sframe_validate_section(struct sframe_section *sec) +{ + unsigned long prev_ip =3D 0; + unsigned int i; + + for (i =3D 0; i < sec->num_fdes; i++) { + struct sframe_fre *fre, *prev_fre =3D NULL; + unsigned long ip, fre_addr; + struct sframe_fde fde; + struct sframe_fre fres[2]; + bool which =3D false; + unsigned int j; + int ret; + + ret =3D safe_read_fde(sec, i, &fde); + if (ret) + return ret; + + ip =3D sec->sframe_start + fde.start_addr; + if (ip <=3D prev_ip) { + dbg_sec("fde %u not sorted\n", i); + return -EFAULT; + } + prev_ip =3D ip; + + fre_addr =3D sec->fres_start + fde.fres_off; + for (j =3D 0; j < fde.fres_num; j++) { + int ret; + + fre =3D which ? fres : fres + 1; + which =3D !which; + + ret =3D safe_read_fre(sec, &fde, fre_addr, fre); + if (ret) { + dbg_sec("fde %u: __read_fre(%u) failed\n", i, j); + dbg_sec("FDE: start_addr:0x%x func_size:0x%x fres_off:0x%x fres_num:%d= info:%u rep_size:%u\n", + fde.start_addr, fde.func_size, + fde.fres_off, fde.fres_num, + fde.info, fde.rep_size); + return ret; + } + + fre_addr +=3D fre->size; + + if (prev_fre && fre->ip_off <=3D prev_fre->ip_off) { + dbg_sec("fde %u: fre %u not sorted\n", i, j); + return -EFAULT; + } + + prev_fre =3D fre; + } + } + + return 0; +} + +#else /* !CONFIG_SFRAME_VALIDATION */ + +static int sframe_validate_section(struct sframe_section *sec) { return 0;= } + +#endif /* !CONFIG_SFRAME_VALIDATION */ + + static void free_section(struct sframe_section *sec) { dbg_free(sec); @@ -427,6 +519,10 @@ int sframe_add_section(unsigned long sframe_start, uns= igned long sframe_end, goto err_free; } =20 + ret =3D sframe_validate_section(sec); + if (ret) + goto err_free; + ret =3D mtree_insert_range(sframe_mt, sec->text_start, sec->text_end, sec= , GFP_KERNEL); if (ret) { dbg_sec("mtree_insert_range failed: text=3D%lx-%lx\n", --=20 2.50.1 From nobody Fri Oct 3 16:46:10 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5030130749E; Wed, 27 Aug 2025 20:24:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; cv=none; b=FZ70ei8u+nKKpRKOOzjSKt1dNcrVBQs1Z05wNfKmBXWd2JYBd5c+zxiJaBi0cmWYLIEk/JtLl79eDRIxAUKEwbHP6q2/BUTAH7g4DDzotO9uFTq4D1yckVmBwxK+BK3+BLxsvT1NixaH12hvn+znK3sVaLYXFKcmKwVuCBkMRTA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756326263; c=relaxed/simple; bh=EcoepKxpaib08JEAUBe/rbQ989EbwLD/UsSh+4p+mfQ=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=J0EsRSQk/CWNAXGTkX9LYHsfRkZJQTHFTSpb/VQr0Q4Md0vf3TkgF83UMxNxnr7X/qh97r3/bc8mG4335XHL2D1znEyQrll+N4llljCx+6Emqc46DxKWMjyTyMJSOsZ6ixncqEocjnmoGlroQbPWVI1QYVuPmXlTj04BYcHD/T0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Wf4MHHj+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Wf4MHHj+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A4E5C4CEFC; Wed, 27 Aug 2025 20:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756326263; bh=EcoepKxpaib08JEAUBe/rbQ989EbwLD/UsSh+4p+mfQ=; h=Date:From:To:Cc:Subject:References:From; b=Wf4MHHj+LWL/MisFVeOoKZQSxnXZ+RqIQMsWDbhQskReHP8F+zA39h4Cn/Ds5csKA wiGC7dJQ3totPlHqfNY0XtNy+5iY7kd4TIDCRQjt2zcJVCRbeCm2gwaZyYymzXHC10 AhIrfoNG5Xk9HekU2Vdn94uoweDozhMVk33FDvZMf5XEAvK3tn36VFIcjLi2HmNaVZ 82KZlUCbNbQQxlFiVF4+r3PVUoKGfXI7ljKTPqKT2Gy+v479mhDUUGMzur05KFlAB8 LPM0n96cDXAQUyZSebvsZNRP6ZkFYHQWPDAM8cKE7yqyUqRS2YzOAAVxltzr/3QdA6 eE93pqNLjQAjQ== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1urMhG-00000003l1K-0OTE; Wed, 27 Aug 2025 16:24:42 -0400 Message-ID: <20250827202441.946968550@kernel.org> User-Agent: quilt/0.68 Date: Wed, 27 Aug 2025 16:15:59 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" Subject: [PATCH v10 11/11] [DO NOT APPLY]unwind_user/sframe: Add prctl() interface for registering .sframe sections References: <20250827201548.448472904@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf The kernel doesn't have direct visibility to the ELF contents of shared libraries. Add some prctl() interfaces which allow glibc to tell the kernel where to find .sframe sections. [ This adds an interface for prctl() for testing loading of sframes for libraries. But this interface should really be a system call. This patch is for testing purposes only and should not be applied to mainline. ] Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- include/uapi/linux/prctl.h | 6 +++++- kernel/sys.c | 9 +++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index ed3aed264aeb..b807baa8a53b 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -358,7 +358,7 @@ struct prctl_mm_map { * configuration. All bits may be locked via this call, including * undefined bits. */ -#define PR_LOCK_SHADOW_STACK_STATUS 76 +#define PR_LOCK_SHADOW_STACK_STATUS 76 =20 /* * Controls the mode of timer_create() for CRIU restore operations. @@ -376,4 +376,8 @@ struct prctl_mm_map { # define PR_FUTEX_HASH_SET_SLOTS 1 # define PR_FUTEX_HASH_GET_SLOTS 2 =20 +/* SFRAME management */ +#define PR_ADD_SFRAME 79 +#define PR_REMOVE_SFRAME 80 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 1e28b40053ce..e6ce79a3a7aa 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -65,6 +65,7 @@ #include #include #include +#include =20 #include =20 @@ -2805,6 +2806,14 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, a= rg2, unsigned long, arg3, case PR_FUTEX_HASH: error =3D futex_hash_prctl(arg2, arg3, arg4); break; + case PR_ADD_SFRAME: + error =3D sframe_add_section(arg2, arg3, arg4, arg5); + break; + case PR_REMOVE_SFRAME: + if (arg3 || arg4 || arg5) + return -EINVAL; + error =3D sframe_remove_section(arg2); + break; default: trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5); error =3D -EINVAL; --=20 2.50.1