From nobody Mon Feb 9 12:01:38 2026 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 3290A21A43D; Fri, 1 Aug 2025 21:03:02 +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=1754082183; cv=none; b=fsbRtzOFZ0zW8+TvuRwvSWOFVAyw9B1UVe5DO8ZpBsiypV4qhCsQoY/79TjV08JVlXUdOGPiVLuqE6/NBUiDCjxeOokg0Tn/1bZZioonl3wTXDlekT92Kc17sOPAPZ9mCTXm/PHF7LiO7EhNugrux4MW83svZ++tkmj1w0tVqAI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754082183; c=relaxed/simple; bh=6gU1IZuL/kDyaT7QNAaYwy8htPH0k5Z8X4DvAqLt6gE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c7H/UJF9gMUmOBIiLkCdHowOJdtBBpcHlpQXJNkvtkgWkcsrK/xbIdGUth5CuSKfSd3e278tQsWigbz6E67LjsW6+61Vp26qS+OK+tiKDX2HpUH9w0jewlcngKmqS+Om6Pq4TzFVnDL1tRbvXzKuKiTRWwcbUPOmoaQzR0HYElA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m12/gnQl; 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="m12/gnQl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 50CDBC4CEE7; Fri, 1 Aug 2025 21:02:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754082182; bh=6gU1IZuL/kDyaT7QNAaYwy8htPH0k5Z8X4DvAqLt6gE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m12/gnQlNLhRByx83c2Pf+AV+GFWLPPrx7+PKFHTkKLtBnzFuF40nhWuD/+Qn51lY fEbMuAe1XRridVdBCc5LaQBStXrKQjTCmNIiRjV8RfBw83yjdv9pmjpBp4BfFyzrhH MNgiU4bNocWu+PUuo/KEzQCX1emr8yILG931IX11YgGMlVYEFjKzwHYGmx4scdw/No 1vPde+J+0CwdtcgUKbmdtgNP8/kCh+K2gtwq2ORy/JSGn9FTsRQ+wqI7emNHaF1KmO EztEW/VDsch8lBGpg7vqykv5zTTDTAXf1SrdTUAA3Odgs4O8mTekiisSstR2WOnAA6 FkGYGfamYd7+Q== From: Jiri Olsa To: Oleg Nesterov , Masami Hiramatsu , Peter Zijlstra , Andrii Nakryiko Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, Song Liu , Yonghong Song , John Fastabend , Hao Luo , Steven Rostedt , Ingo Molnar Subject: [RFC 1/4] uprobe: Do not emulate/sstep original instruction when ip is changed Date: Fri, 1 Aug 2025 23:02:35 +0200 Message-ID: <20250801210238.2207429-2-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250801210238.2207429-1-jolsa@kernel.org> References: <20250801210238.2207429-1-jolsa@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" If uprobe handler changes instruction pointer we still execute single step) or emulate the original instruction and increment the (new) ip with its length. This makes the new instruction pointer bogus and application will likely crash on illegal instruction execution. If user decided to take execution elsewhere, it makes little sense to execute the original instruction, so let's skip it. Signed-off-by: Jiri Olsa --- kernel/events/uprobes.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 4c965ba77f9f..dff5509cde67 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -2742,6 +2742,9 @@ static void handle_swbp(struct pt_regs *regs) =20 handler_chain(uprobe, regs); =20 + if (instruction_pointer(regs) !=3D bp_vaddr) + goto out; + if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) goto out; =20 --=20 2.50.1 From nobody Mon Feb 9 12:01:38 2026 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 56B7821A43D; Fri, 1 Aug 2025 21:03:14 +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=1754082194; cv=none; b=MIaXveOdWGQ19+ctQDOahiKtWILeo1fZjhB6twYsXhj6rIUbi1qyGoWbX/rG+x/4hAyecdz4LxVgg80JElMHeuiYt1k2G88JeqPwTov/EjY3kVY/HZSsk26uBQYBbqIkyj/5w5HJDCtvzwfzMMXg0JNu/nuo36pO6PNI3TbE1S4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754082194; c=relaxed/simple; bh=0RmjoFSsHQJXWphY2gRGBMuPj3H+tw0ROuPOh0jMxIQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HmZKBQZ441S+bDoBzWOX9fCrsPsybL4prf9qXiMPhsS12t5auH9tWT2xYGXPmPdtEtKf/sQh3UFFffOGtDSSoNEirZMlCqg1cpsflh0tDsFTU2g5IWlKg6jQqNaQeKELLoEdySCSd8wxTmfTEoltDMs0UCsJzJXyyuVJTQRkwd8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m3HaIabD; 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="m3HaIabD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FD4CC4CEE7; Fri, 1 Aug 2025 21:03:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754082193; bh=0RmjoFSsHQJXWphY2gRGBMuPj3H+tw0ROuPOh0jMxIQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m3HaIabD9dOEu/iXFt7ZO1+JAaMCp8S4jlY9k0GI66F5I//5gajvTJtw/x371t3e5 r4DgxrJvRZpI0+zB0TEl/UYkn5bOoUWXmKBUbWWTbX+ZoSM5AtjJSMVperGBgNUluw j5h8PWKih7Z1lmH03Md8WZQjepeP73s8lp6eRgFFuhGgC+ePrXAdW+nIdSkWWoGYGF mMn/ZCMz5TyCopw4uwcvCZqAIPoAZyCM/YlFAZ/9pf+iSjL7xFZvguqcOtPoIRw0zK rkqBbhCWUR4l45SnbE4pCi83qHhKEqn+yMMxccTsxnZebkrf56SwuVveFtvtQPLp1+ aXEeQ7XbIc8qg== From: Jiri Olsa To: Oleg Nesterov , Masami Hiramatsu , Peter Zijlstra , Andrii Nakryiko Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, Song Liu , Yonghong Song , John Fastabend , Hao Luo , Steven Rostedt , Ingo Molnar Subject: [RFC 2/4] bpf: Allow uprobe program to change context registers Date: Fri, 1 Aug 2025 23:02:36 +0200 Message-ID: <20250801210238.2207429-3-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250801210238.2207429-1-jolsa@kernel.org> References: <20250801210238.2207429-1-jolsa@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" Currently uprobe (BPF_PROG_TYPE_KPROBE) program can't write to the context registers data. While this makes sense for kprobe attachments, for uprobe attachment it might make sense to be able to change user space registers to alter application execution. Since uprobe and kprobe programs share the same type (BPF_PROG_TYPE_KPROBE), we can't deny write access to context during the program load. We need to check on it during program attachment to see if it's going to be kprobe or uprobe. Storing the program's write attempt to context and checking on it during the attachment. Signed-off-by: Jiri Olsa --- include/linux/bpf.h | 1 + kernel/events/core.c | 4 ++++ kernel/trace/bpf_trace.c | 3 +-- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f9cd2164ed23..8c8bd00e0095 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1609,6 +1609,7 @@ struct bpf_prog_aux { bool priv_stack_requested; bool changes_pkt_data; bool might_sleep; + bool kprobe_write_ctx; u64 prog_array_member_cnt; /* counts how many times as member of prog_arr= ay */ struct mutex ext_mutex; /* mutex for is_extended and prog_array_member_cn= t */ struct bpf_arena *arena; diff --git a/kernel/events/core.c b/kernel/events/core.c index 22fdf0c187cd..4eaeeb40aa08 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11205,6 +11205,10 @@ static int __perf_event_set_bpf_prog(struct perf_e= vent *event, if (prog->kprobe_override && !is_kprobe) return -EINVAL; =20 + /* Writing to context allowed only for uprobes. */ + if (prog->aux->kprobe_write_ctx && !is_uprobe) + return -EINVAL; + if (is_tracepoint || is_syscall_tp) { int off =3D trace_event_get_offsets(event->tp_event); =20 diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3ae52978cae6..467fd5ab4b79 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1521,8 +1521,6 @@ static bool kprobe_prog_is_valid_access(int off, int = size, enum bpf_access_type { if (off < 0 || off >=3D sizeof(struct pt_regs)) return false; - if (type !=3D BPF_READ) - return false; if (off % size !=3D 0) return false; /* @@ -1532,6 +1530,7 @@ static bool kprobe_prog_is_valid_access(int off, int = size, enum bpf_access_type if (off + size > sizeof(struct pt_regs)) return false; =20 + prog->aux->kprobe_write_ctx |=3D type =3D=3D BPF_WRITE; return true; } =20 --=20 2.50.1 From nobody Mon Feb 9 12:01:38 2026 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 593C021A43D; Fri, 1 Aug 2025 21:03:25 +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=1754082205; cv=none; b=q3Ll0Xv1c84pK9agB1t21NbFNFQfyyUJq6h8vZt6L1Vpm7LTJhys/Go1wXPy1nHUSX+uycbjchWDq7LnqjzJCMsItVIUeaaD4m+JYVrEo8E2V1gIJjM4T7OWVgrsapI4Dgd2nH1t1JiHOKwyConF7oo2X32FpKcSSXj5eKXwo3Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754082205; c=relaxed/simple; bh=KYbFs6eVhmHrxJWcJu9e1K7ukD2n+TidNSo/g29/c4Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iiqTQ7cbxO4uHgKTJQ+ckZfLQngtyuXxuBp0qbsMErVWpB4ssUZcWwmrmFKrGCRFOpxFAmy11JVyxbaR6SvviiYugvD3E5Qv5E4mNXvFxaEJXIiD7lTr4rIs1nORakiSVlA41EyLxSazFMpLSU5XyOHwWH/BWGpAcxUo35n1vuQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XBEbhwCP; 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="XBEbhwCP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E2AAC4CEE7; Fri, 1 Aug 2025 21:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754082205; bh=KYbFs6eVhmHrxJWcJu9e1K7ukD2n+TidNSo/g29/c4Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XBEbhwCP4Rn8oXTdTjhaKQfrBaYYeYe5O29n3qaA8urL1cJgs1y9l/EJAKWhJRxVu q7ugr4WeYLEgFSM0soAxLcsaAdUyZJbpb1jgSFZzA1akkg8TYaQeXw82dbblFnlPhW p6iACtsdBi09YNjmseOE1b7iomeWJSIR3yEezfmUhXT4eQcg9zF34v74Al7nFvxFBh ovoBo/ewe82FJCq4qmOzHwDNtdQgzXjV9zfPaaSTZ3+d5U5YhMwldC3Q4Qqz1/vXoT QTMcsmVKQempAoJP/xbdtdFK3WAwi5V6yCEfhMKDmAwekkPqbr1DMopkYPes/8RzJF dLMBw8GyicZsg== From: Jiri Olsa To: Oleg Nesterov , Masami Hiramatsu , Peter Zijlstra , Andrii Nakryiko Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, Song Liu , Yonghong Song , John Fastabend , Hao Luo , Steven Rostedt , Ingo Molnar Subject: [RFC 3/4] selftests/bpf: Add uprobe context registers changes test Date: Fri, 1 Aug 2025 23:02:37 +0200 Message-ID: <20250801210238.2207429-4-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250801210238.2207429-1-jolsa@kernel.org> References: <20250801210238.2207429-1-jolsa@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" Adding test to check we can change common register values through uprobe program. It's x86_64 specific test. Signed-off-by: Jiri Olsa --- .../testing/selftests/bpf/prog_tests/uprobe.c | 114 +++++++++++++++++- .../testing/selftests/bpf/progs/test_uprobe.c | 24 ++++ 2 files changed, 137 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe.c b/tools/testin= g/selftests/bpf/prog_tests/uprobe.c index cf3e0e7a64fa..7c7cb08d10b3 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe.c @@ -2,6 +2,7 @@ /* Copyright (c) 2023 Hengqi Chen */ =20 #include +#include #include "test_uprobe.skel.h" =20 static FILE *urand_spawn(int *pid) @@ -33,7 +34,7 @@ static int urand_trigger(FILE **urand_pipe) return exit_code; } =20 -void test_uprobe(void) +static void test_uprobe_attach(void) { LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); struct test_uprobe *skel; @@ -93,3 +94,114 @@ void test_uprobe(void) pclose(urand_pipe); test_uprobe__destroy(skel); } + +#ifdef __x86_64__ +__naked __maybe_unused unsigned long uprobe_regs_change_trigger(void) +{ + asm volatile ( + "ret\n" + ); +} + +static __naked void uprobe_regs_change(struct pt_regs *before, struct pt_r= egs *after) +{ + asm volatile ( + "movq %r11, 48(%rdi)\n" + "movq %r10, 56(%rdi)\n" + "movq %r9, 64(%rdi)\n" + "movq %r8, 72(%rdi)\n" + "movq %rax, 80(%rdi)\n" + "movq %rcx, 88(%rdi)\n" + "movq %rdx, 96(%rdi)\n" + "movq %rsi, 104(%rdi)\n" + "movq %rdi, 112(%rdi)\n" + + /* save 2nd argument */ + "pushq %rsi\n" + "call uprobe_regs_change_trigger\n" + + /* save return value and load 2nd argument pointer to rax */ + "pushq %rax\n" + "movq 8(%rsp), %rax\n" + + "movq %r11, 48(%rax)\n" + "movq %r10, 56(%rax)\n" + "movq %r9, 64(%rax)\n" + "movq %r8, 72(%rax)\n" + "movq %rcx, 88(%rax)\n" + "movq %rdx, 96(%rax)\n" + "movq %rsi, 104(%rax)\n" + "movq %rdi, 112(%rax)\n" + + /* restore return value and 2nd argument */ + "pop %rax\n" + "pop %rsi\n" + + "movq %rax, 80(%rsi)\n" + "ret\n" + ); +} + +static void regs_common(void) +{ + struct pt_regs before =3D {}, after =3D {}, expected =3D { + .rax =3D 0xc0ffe, + .rcx =3D 0xbad, + .rdx =3D 0xdead, + .r8 =3D 0x8, + .r9 =3D 0x9, + .r10 =3D 0x10, + .r11 =3D 0x11, + .rdi =3D 0x12, + .rsi =3D 0x13, + }; + LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); + struct test_uprobe *skel; + + skel =3D test_uprobe__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->my_pid =3D getpid(); + skel->bss->regs =3D expected; + + uprobe_opts.func_name =3D "uprobe_regs_change_trigger"; + skel->links.test_regs_change =3D bpf_program__attach_uprobe_opts(skel->pr= ogs.test_regs_change, + -1, + "/proc/self/exe", + 0 /* offset */, + &uprobe_opts); + if (!ASSERT_OK_PTR(skel->links.test_regs_change, "bpf_program__attach_upr= obe_opts")) + goto cleanup; + + uprobe_regs_change(&before, &after); + + ASSERT_EQ(after.rax, expected.rax, "ax"); + ASSERT_EQ(after.rcx, expected.rcx, "cx"); + ASSERT_EQ(after.rdx, expected.rdx, "dx"); + ASSERT_EQ(after.r8, expected.r8, "r8"); + ASSERT_EQ(after.r9, expected.r9, "r9"); + ASSERT_EQ(after.r10, expected.r10, "r10"); + ASSERT_EQ(after.r11, expected.r11, "r11"); + ASSERT_EQ(after.rdi, expected.rdi, "rdi"); + ASSERT_EQ(after.rsi, expected.rsi, "rsi"); + +cleanup: + test_uprobe__destroy(skel); +} + +static void test_uprobe_regs_change(void) +{ + if (test__start_subtest("regs_change_common")) + regs_common(); +} +#else +static void test_uprobe_regs_change(void) { } +#endif + +void test_uprobe(void) +{ + if (test__start_subtest("attach")) + test_uprobe_attach(); + test_uprobe_regs_change(); +} diff --git a/tools/testing/selftests/bpf/progs/test_uprobe.c b/tools/testin= g/selftests/bpf/progs/test_uprobe.c index 896c88a4960d..9437bd76a437 100644 --- a/tools/testing/selftests/bpf/progs/test_uprobe.c +++ b/tools/testing/selftests/bpf/progs/test_uprobe.c @@ -59,3 +59,27 @@ int BPF_UPROBE(test4) test4_result =3D 1; return 0; } + +#if defined(__TARGET_ARCH_x86) +struct pt_regs regs; + +SEC("uprobe") +int BPF_UPROBE(test_regs_change) +{ + pid_t pid =3D bpf_get_current_pid_tgid() >> 32; + + if (pid !=3D my_pid) + return 0; + + ctx->ax =3D regs.ax; + ctx->cx =3D regs.cx; + ctx->dx =3D regs.dx; + ctx->r8 =3D regs.r8; + ctx->r9 =3D regs.r9; + ctx->r10 =3D regs.r10; + ctx->r11 =3D regs.r11; + ctx->di =3D regs.di; + ctx->si =3D regs.si; + return 0; +} +#endif --=20 2.50.1 From nobody Mon Feb 9 12:01:38 2026 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 7B1D52147F9; Fri, 1 Aug 2025 21:03:36 +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=1754082217; cv=none; b=te9V4mWhn2/XD45gwoLwCJKp46VS7hzLaFkSlEhAuiDFM3FpqT9bzrd5EPK5cPxt9T+NdF+dRBUq8P7a443AqFyu4V0HXCz+b6Bp8/WTmSvkre3kRt6CLXCxC5bh8sFBg1cTunLisS8JFIJ3BmWqShCTaHtDvd4nEhlwxI856b4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754082217; c=relaxed/simple; bh=2IgccXrML8eTSCHq8i8NG7mRfzsM4SW1DbQbW7h/63o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bs2r+VbAu0BtEPiF87ptSyxGiLghJYAvzuGITcdR/bMiN5HeVS9RCgBNoM6kXKlm7sMdjmfo2gVPeWtTRLDAqKlGM7SFCSLwN8WLBZye5WjuQPgCfH4bJ7y/nI6rGL6KPNs0WhCkxp10988XD2TDG6M9GF3/1qedEoBaTKqgzN0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qTcBVxfF; 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="qTcBVxfF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BEC1C4CEE7; Fri, 1 Aug 2025 21:03:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754082215; bh=2IgccXrML8eTSCHq8i8NG7mRfzsM4SW1DbQbW7h/63o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qTcBVxfF+mhViauYFPTaQyiIlVGrpqFWWl4i6C1BKv/Njn5gmxCz6PgMx4v3BzLd+ /kl8gsPpO9wumGLVGPt+EGMLfU4w2OWitzrAmr5bnL/QwnpAiTS6LsJIjbTUi3PtGm 2uvHOjUr6mP2Li8o6fUO7xPQ1Xj8xmVNRD9SANSZwoiHoyeSqZXTwslsIJMxsF28hC XhkOOkrm6SFq2uKVsudFQqlD1AmDEuIhzlfAgbRd3XVkJ0n9u/1biG7XPjLV41B4C4 Dqq8NvbDU5GxOD5YFSvBpMkc1gpfA7ZpI7KbYqK+QRvd1X+autuUfG86wwv98qYgsV boHwO1XVfOPGg== From: Jiri Olsa To: Oleg Nesterov , Masami Hiramatsu , Peter Zijlstra , Andrii Nakryiko Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, Song Liu , Yonghong Song , John Fastabend , Hao Luo , Steven Rostedt , Ingo Molnar Subject: [RFC 4/4] selftests/bpf: Add uprobe context ip register change test Date: Fri, 1 Aug 2025 23:02:38 +0200 Message-ID: <20250801210238.2207429-5-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250801210238.2207429-1-jolsa@kernel.org> References: <20250801210238.2207429-1-jolsa@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" Adding test to check we can change the application execution through instruction pointer change through uprobe program. It's x86_64 specific test. Signed-off-by: Jiri Olsa --- .../testing/selftests/bpf/prog_tests/uprobe.c | 48 +++++++++++++++++++ .../testing/selftests/bpf/progs/test_uprobe.c | 14 ++++++ 2 files changed, 62 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe.c b/tools/testin= g/selftests/bpf/prog_tests/uprobe.c index 7c7cb08d10b3..05cd3b65260f 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe.c @@ -190,10 +190,58 @@ static void regs_common(void) test_uprobe__destroy(skel); } =20 +static __naked unsigned long uprobe_regs_change_ip_1(void) +{ + asm volatile ( + "movq $0xc0ffee, %rax\n" + "ret\n" + ); +} + +static __naked unsigned long uprobe_regs_change_ip_2(void) +{ + asm volatile ( + "movq $0xdeadbeef, %rax\n" + "ret\n" + ); +} + +static void regs_ip(void) +{ + LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); + struct test_uprobe *skel; + unsigned long ret; + + skel =3D test_uprobe__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->my_pid =3D getpid(); + skel->bss->ip =3D (unsigned long) uprobe_regs_change_ip_2; + + uprobe_opts.func_name =3D "uprobe_regs_change_ip_1"; + skel->links.test_regs_change_ip =3D bpf_program__attach_uprobe_opts( + skel->progs.test_regs_change_ip, + -1, + "/proc/self/exe", + 0 /* offset */, + &uprobe_opts); + if (!ASSERT_OK_PTR(skel->links.test_regs_change_ip, "bpf_program__attach_= uprobe_opts")) + goto cleanup; + + ret =3D uprobe_regs_change_ip_1(); + ASSERT_EQ(ret, 0xdeadbeef, "ret"); + +cleanup: + test_uprobe__destroy(skel); +} + static void test_uprobe_regs_change(void) { if (test__start_subtest("regs_change_common")) regs_common(); + if (test__start_subtest("regs_change_ip")) + regs_ip(); } #else static void test_uprobe_regs_change(void) { } diff --git a/tools/testing/selftests/bpf/progs/test_uprobe.c b/tools/testin= g/selftests/bpf/progs/test_uprobe.c index 9437bd76a437..12f4065fca20 100644 --- a/tools/testing/selftests/bpf/progs/test_uprobe.c +++ b/tools/testing/selftests/bpf/progs/test_uprobe.c @@ -82,4 +82,18 @@ int BPF_UPROBE(test_regs_change) ctx->si =3D regs.si; return 0; } + +unsigned long ip; + +SEC("uprobe") +int BPF_UPROBE(test_regs_change_ip) +{ + pid_t pid =3D bpf_get_current_pid_tgid() >> 32; + + if (pid !=3D my_pid) + return 0; + + ctx->ip =3D ip; + return 0; +} #endif --=20 2.50.1