From nobody Tue Sep 29 06:05:24 2026 Received: from out-185.mta1.migadu.com (out-185.mta1.migadu.com [95.215.58.185]) (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 81B503793B3 for ; Wed, 12 Aug 2026 05:41:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.185 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786513266; cv=none; b=DNKB5ZpEGSD7x4Hk4kiOslP7qbrmmjIp6m0OaXA59upV+Qfg9vjOEwiB9jTQ6RNFeb3r9+5tTbh3stsPxQ9EUkAb6GhxoDRQpDZNEOh7NTC5kP8TZLV2pctlpFDaguBfrOjbtS6VJkcDMUPsrd4Z1i5dSANd9jzrSoRa0uM9OvI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786513266; c=relaxed/simple; bh=OOCV03Txm58/nC1xVoqeRZ8PocwYKDqJa9WPQo6SUas=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VOQKypRhWE5tIKUkWmmAKNoctNBliRF30LchjU4JHb2Jz9ajfWsRHIZ034VklUKAi3kW2q/m6/tSO4Os1eOq34U2hlAC0YFfxUM3h6YTjmZHbVg14LqD3VRHsHwwE4LQj2t8Ot8JNz9nSf/jE35gt72Dx9sN+02C751Gk8m+xQk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=QrHRZra0; arc=none smtp.client-ip=95.215.58.185 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="QrHRZra0" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1786513262; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bJefnKdyyVU6NP3rSxhHMvWH6C76JvPIyTZYHfrF4TA=; b=QrHRZra0d0oMGEigxQe/Homsx9vdjks6wFLQ1hFnx/AzQPiam4RRF32oxnU9JqB9+pF861 eKbAeAGGchjXgw2qQpcl50hhXLwiIZF4Pu78nuy7A3hzOvtQaE6wLy/XrxMNuLIb0Zfi5r vl+tD5IQW9MDinWepMWCNp8CYs+SYeo= From: Hao Ge To: Suren Baghdasaryan , Andrew Morton , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hao Ge , stable@vger.kernel.org Subject: [PATCH v5 1/2] alloc_tag: move release_module_tags() above reserve_module_tags() Date: Wed, 12 Aug 2026 13:41:04 +0800 Message-Id: <20260812054105.102637-2-hao.ge@linux.dev> In-Reply-To: <20260812054105.102637-1-hao.ge@linux.dev> References: <20260812054105.102637-1-hao.ge@linux.dev> 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 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" release_module_tags() is a cleanup helper. reserve_module_tags() can also fail after storing the reservation in the maple tree, in which case it should call release_module_tags() to undo it. Move the helper above reserve_module_tags() so no forward declaration is needed. No functional change. Fixes: 4835f747d3ed ("alloc_tag: support for page allocation tag compressio= n") Cc: stable@vger.kernel.org Signed-off-by: Hao Ge Acked-by: Suren Baghdasaryan --- mm/alloc_tag.c | 92 +++++++++++++++++++++++++------------------------- 1 file changed, 46 insertions(+), 46 deletions(-) diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c index 52aece27b00e..af44f90379f2 100644 --- a/mm/alloc_tag.c +++ b/mm/alloc_tag.c @@ -835,6 +835,52 @@ static int vm_module_tags_populate(void) return 0; } =20 +static void release_module_tags(struct module *mod, bool used) +{ + MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size); + struct alloc_tag *start_tag; + struct alloc_tag *end_tag; + struct module *val; + + mas_lock(&mas); + mas_for_each_rev(&mas, val, 0) + if (val =3D=3D mod) + break; + + if (!val) /* module not found */ + goto out; + + if (!used) + goto release_area; + + start_tag =3D (struct alloc_tag *)(module_tags.start_addr + mas.index); + end_tag =3D (struct alloc_tag *)(module_tags.start_addr + mas.last); + if (!clean_unused_counters(start_tag, end_tag)) { + struct alloc_tag *tag; + + for (tag =3D start_tag; tag <=3D end_tag; tag++) { + struct alloc_tag_counters counter; + + if (!tag->counters) + continue; + + counter =3D alloc_tag_read(tag); + pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n", + tag->ct.filename, tag->ct.lineno, tag->ct.modname, + tag->ct.function, counter.bytes); + } + } else { + used =3D false; + } +release_area: + mas_store(&mas, used ? &unloaded_mod : NULL); + val =3D mas_prev_range(&mas, 0); + if (val =3D=3D &prepend_mod) + mas_store(&mas, NULL); +out: + mas_unlock(&mas); +} + static void *reserve_module_tags(struct module *mod, unsigned long size, unsigned int prepend, unsigned long align) { @@ -922,52 +968,6 @@ static void *reserve_module_tags(struct module *mod, u= nsigned long size, return (struct alloc_tag *)(module_tags.start_addr + offset); } =20 -static void release_module_tags(struct module *mod, bool used) -{ - MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size); - struct alloc_tag *start_tag; - struct alloc_tag *end_tag; - struct module *val; - - mas_lock(&mas); - mas_for_each_rev(&mas, val, 0) - if (val =3D=3D mod) - break; - - if (!val) /* module not found */ - goto out; - - if (!used) - goto release_area; - - start_tag =3D (struct alloc_tag *)(module_tags.start_addr + mas.index); - end_tag =3D (struct alloc_tag *)(module_tags.start_addr + mas.last); - if (!clean_unused_counters(start_tag, end_tag)) { - struct alloc_tag *tag; - - for (tag =3D start_tag; tag <=3D end_tag; tag++) { - struct alloc_tag_counters counter; - - if (!tag->counters) - continue; - - counter =3D alloc_tag_read(tag); - pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n", - tag->ct.filename, tag->ct.lineno, tag->ct.modname, - tag->ct.function, counter.bytes); - } - } else { - used =3D false; - } -release_area: - mas_store(&mas, used ? &unloaded_mod : NULL); - val =3D mas_prev_range(&mas, 0); - if (val =3D=3D &prepend_mod) - mas_store(&mas, NULL); -out: - mas_unlock(&mas); -} - static int load_module(struct module *mod, struct codetag *start, struct c= odetag *stop) { /* Allocate module alloc_tag percpu counters */ --=20 2.25.1 From nobody Tue Sep 29 06:05:24 2026 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (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 06AD43921DD; Wed, 12 Aug 2026 05:41:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786513271; cv=none; b=KJUVtLwqZ6qwuF+aX3gteKVJzfzOuGto6mIsrSBil+dz8H2gyTdTo6zq8iTu9lIi0+I97m8d7wk5l/L7+So/V7+RAlxqZhmdoo+mS79E0VsgRfwscMAR7mdS2ZIjEyVJqCZfY8vmQR+1SKsEWveyvJlefZ2EIm8lQq70AH3adqA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786513271; c=relaxed/simple; bh=E6uGsbGqqzCkRoxACNAXopQ2UoUWKRxtKe6zwPPJj0w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=K1Ivu3bRjuY+RB+ZXeIcZx1i3Yw2t1MzgKkz+pWova9y1wk4fXSM6UbD+6BQ4rs7HbSIHP0lYHPoezveprVADRbWLcJqNmZqLefHtdQgsC/6JOsfXatMNtzVsO3ySj+XVFAlXEPLehmK61RD0oEcJYuERrJaczU8wwmlrf2Ze/U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Whpnxh9p; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Whpnxh9p" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1786513266; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TJw8Kb7KYo62APlX8MEZxvAZlhH4o0ziACenqfJhSwk=; b=Whpnxh9pXp2+bTxNYX9GyGV2YNWyFmEhiFLBxTHM1emfN+vJjElCcTotxQwVy3X1umLo6t yiTOJm0OqPnobb7aV185QEy//Yh3hnbhvUFaABU9uMRD6FwBkggx2YIhowltCfc/AyM1lq HTTnFTnQdY/3c7KPSiV2czkyKaweldU= From: Hao Ge To: Suren Baghdasaryan , Andrew Morton , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hao Ge , stable@vger.kernel.org Subject: [PATCH v5 2/2] alloc_tag: fix undetected compressed tag overflow when profiling is disabled Date: Wed, 12 Aug 2026 13:41:05 +0800 Message-Id: <20260812054105.102637-3-hao.ge@linux.dev> In-Reply-To: <20260812054105.102637-1-hao.ge@linux.dev> References: <20260812054105.102637-1-hao.ge@linux.dev> 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 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" In reserve_module_tags(), the tag overflow check is gated on mem_alloc_profiling_enabled(): if (mem_alloc_profiling_enabled() && !tags_addressable()) If profiling is toggled off at runtime and a module is loaded whose tags exceed the compressed-mode limit, shutdown_mem_profiling() is skipped. vm_module_tags_populate() still maps memory for the tags and the module loads successfully, but the total tag count now exceeds what NR_UNUSED_PAGEFLAG_BITS can address. Once profiling is re-enabled, ref_to_idx() computes each tag's index as its position in the alloc_tag array. update_page_tag_ref() masks it to alloc_tag_ref_mask before storing in page->flags. Indices beyond the mask are truncated and idx_to_ref() resolves them to wrong tags. This silently corrupts /proc/allocinfo: allocated pages get attributed to the wrong call sites, so the statistics it reports are wrong. mem_alloc_profiling_enabled() and mem_profiling_compressed are independent. Once compressed mode is established at boot, it stays active regardless of runtime toggles of mem_profiling. Remove the mem_alloc_profiling_enabled() guard. On overflow, shut down profiling, release the reservation, and return -EAGAIN so that layout_and_allocate() retries with profiling disabled: codetag sections are then placed as regular module data and the module loads without profiling rather than being rejected entirely. Fixes: 4835f747d3ed ("alloc_tag: support for page allocation tag compressio= n") Cc: stable@vger.kernel.org Suggested-by: Suren Baghdasaryan Signed-off-by: Hao Ge Acked-by: Suren Baghdasaryan --- kernel/module/main.c | 25 +++++++++++++++++++++++-- mm/alloc_tag.c | 8 +++++--- 2 files changed, 28 insertions(+), 5 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 46dd8d25a605..ed26f167be84 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load= _info *info, int flags) { struct module *mod; int err; + unsigned long frob_size[MOD_MEM_NUM_TYPES]; =20 /* Allow arches to frob section contents and sizes. */ err =3D module_frob_arch_sections(info->hdr, info->sechdrs, @@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct lo= ad_info *info, int flags) */ module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings); =20 + /* + * Save the sizes reserved by module_frob_arch_sections() so they can + * be restored if we retry below. + */ + for_each_mod_mem_type(type) + frob_size[type] =3D info->mod->mem[type].size; + /* * Determine total sizes, and put offsets in sh_entsize. For now * this is done generically; there doesn't appear to be any * special cases for the architectures. */ +retry: layout_sections(info->mod, info); layout_symtab(info->mod, info); =20 /* Allocate and move to the final place */ err =3D move_module(info->mod, info); - if (err) - return ERR_PTR(err); + if (err) { + if (err !=3D -EAGAIN) + return ERR_PTR(err); + /* + * -EAGAIN means profiling was disabled but the module + * can still load without it. Reset state and retry. + */ + rewrite_section_headers(info, flags); + for_each_mod_mem_type(type) + info->mod->mem[type].size =3D frob_size[type]; + info->sechdrs[info->index.sym].sh_flags &=3D ~(unsigned long)SHF_ALLOC; + info->sechdrs[info->index.str].sh_flags &=3D ~(unsigned long)SHF_ALLOC; + goto retry; + } =20 /* Module has been copied to its final place now: return it. */ mod =3D (void *)info->sechdrs[info->index.mod].sh_addr; diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c index af44f90379f2..0a7b657fe2de 100644 --- a/mm/alloc_tag.c +++ b/mm/alloc_tag.c @@ -950,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, = unsigned long size, int grow_res; =20 module_tags.size =3D offset + size; - if (mem_alloc_profiling_enabled() && !tags_addressable()) { + if (!tags_addressable()) { shutdown_mem_profiling(true); - pr_warn("With module %s there are too many tags to fit in %d page flag = bits. Memory allocation profiling is disabled!\n", - mod->name, NR_UNUSED_PAGEFLAG_BITS); + pr_warn_once("With module %s there are too many tags to fit in %d page = flag bits. Memory allocation profiling is disabled!\n", + mod->name, NR_UNUSED_PAGEFLAG_BITS); + release_module_tags(mod, false); + return ERR_PTR(-EAGAIN); } =20 grow_res =3D vm_module_tags_populate(); --=20 2.25.1