From nobody Mon Oct 6 19:10:52 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 D820A1F95C; Thu, 17 Jul 2025 17:33:11 +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=1752773592; cv=none; b=ouX5sLMgnIH8Znse9l1lgB3lASgpGACcexNVA/uiSbeeQ4vdU5SX/Pm56gKqXPkwzG/OWiBWiBhwkA3iN+vFyPnfsP2H+BlVDhASorqebafrTBRxOJSWwc6saElubiGXhMCRVRxmXlomSnQsoK/QKxLYWfOB4Z60bBIDU251Gtw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773592; c=relaxed/simple; bh=PlMed3FiOV4T6l6o16L8MmIemjqgKth6Lso3Lz/CSCM=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=rambXSDm8sZk73hc5pY+9Kfelk0NSFmkRbmGa4moGrMz+uukSq3Zv0Ns2MlW7b5GQxhaUngiloiXdYzOLzznGNa5WL8USW1XaYZQTkZLy+8v3RlEvR7XpD3jDQ/Jh0Rivjvq5VvwUvAhZSA7QZhaJn6L8AKseUvYTm26NCGUVLg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fHdS9iBd; 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="fHdS9iBd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 83511C4CEED; Thu, 17 Jul 2025 17:33:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752773591; bh=PlMed3FiOV4T6l6o16L8MmIemjqgKth6Lso3Lz/CSCM=; h=Date:From:To:Cc:Subject:References:From; b=fHdS9iBd1CaH3EGr2zl1Q0VGhIEXTFpsm1YZio1TTgQR/ehZPmA7kEXcKhXlMx/fg 5gjDrQm8OiovNmwBE/EuQ4coURkSc/HiI3d4X2xjc4NfLOcfWjdTqb9ToqZ48h9NGC Zt7oFhumhuEaXzqQR/WZ/1degS5qp2xKUu6LkbKBj09ZA7AhRy34cnxDRFkWiki3sG VVF7bEakM28X64+Ue+l1JBsWrqfRa68vdutXCvlc9jQ+WUpCTFOjrhD0wRJ9dGDBFn DfptXNdafvksOXaXP5u1w2p4G8DWlEtVMOKDfEFFRLlSUoMBNqUmYxh3SruoYUD1TL 6Tu2b8R0XS4zg== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1ucSU9-00000006byk-1BQn; Thu, 17 Jul 2025 13:33:33 -0400 Message-ID: <20250717173333.141133447@kernel.org> User-Agent: quilt/0.68 Date: Thu, 17 Jul 2025 13:31:26 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Linus Torvalds , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Namhyung Kim , Alexei Starovoitov , Jens Axboe , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton , Namhyung Kim , Alexei Starovoitov Subject: [PATCH 1/5] perf: Remove get_perf_callchain() init_nr argument References: <20250717173125.434618999@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 'init_nr' argument has double duty: it's used to initialize both the number of contexts and the number of stack entries. That's confusing and the callers always pass zero anyway. Hard code the zero. Acked-by: Namhyung Kim Acked-by: Alexei Starovoitov Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- include/linux/perf_event.h | 2 +- kernel/bpf/stackmap.c | 4 ++-- kernel/events/callchain.c | 12 ++++++------ kernel/events/core.c | 2 +- 4 files changed, 10 insertions(+), 10 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index ec9d96025683..54e0d31afcad 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1719,7 +1719,7 @@ DECLARE_PER_CPU(struct perf_callchain_entry, perf_cal= lchain_entry); extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, st= ruct pt_regs *regs); extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, = struct pt_regs *regs); extern struct perf_callchain_entry * -get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool us= er, +get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, u32 max_stack, bool crosstask, bool add_mark); extern int get_callchain_buffers(int max_stack); extern void put_callchain_buffers(void); diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 3615c06b7dfa..ec3a57a5fba1 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -314,7 +314,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, str= uct bpf_map *, map, if (max_depth > sysctl_perf_event_max_stack) max_depth =3D sysctl_perf_event_max_stack; =20 - trace =3D get_perf_callchain(regs, 0, kernel, user, max_depth, + trace =3D get_perf_callchain(regs, kernel, user, max_depth, false, false); =20 if (unlikely(!trace)) @@ -451,7 +451,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struc= t task_struct *task, else if (kernel && task) trace =3D get_callchain_entry_for_task(task, max_depth); else - trace =3D get_perf_callchain(regs, 0, kernel, user, max_depth, + trace =3D get_perf_callchain(regs, kernel, user, max_depth, crosstask, false); =20 if (unlikely(!trace) || trace->nr < skip) { diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 6c83ad674d01..b0f5bd228cd8 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -217,7 +217,7 @@ static void fixup_uretprobe_trampoline_entries(struct p= erf_callchain_entry *entr } =20 struct perf_callchain_entry * -get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool us= er, +get_perf_callchain(struct pt_regs *regs, bool kernel, bool user, u32 max_stack, bool crosstask, bool add_mark) { struct perf_callchain_entry *entry; @@ -228,11 +228,11 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr,= bool kernel, bool user, if (!entry) return NULL; =20 - ctx.entry =3D entry; - ctx.max_stack =3D max_stack; - ctx.nr =3D entry->nr =3D init_nr; - ctx.contexts =3D 0; - ctx.contexts_maxed =3D false; + ctx.entry =3D entry; + ctx.max_stack =3D max_stack; + ctx.nr =3D entry->nr =3D 0; + ctx.contexts =3D 0; + ctx.contexts_maxed =3D false; =20 if (kernel && !user_mode(regs)) { if (add_mark) diff --git a/kernel/events/core.c b/kernel/events/core.c index 0db36b2b2448..b2a53cabcb17 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8178,7 +8178,7 @@ perf_callchain(struct perf_event *event, struct pt_re= gs *regs) if (!kernel && !user) return &__empty_callchain; =20 - callchain =3D get_perf_callchain(regs, 0, kernel, user, + callchain =3D get_perf_callchain(regs, kernel, user, max_stack, crosstask, true); return callchain ?: &__empty_callchain; } --=20 2.47.2 From nobody Mon Oct 6 19:10:52 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 D86B2287254; 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charset="utf-8" From: Josh Poimboeuf get_perf_callchain() doesn't support cross-task unwinding for user space stacks, have it return NULL if both the crosstask and user arguments are set. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- kernel/events/callchain.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index b0f5bd228cd8..cd0e3fc7ed05 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -224,6 +224,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, = bool user, struct perf_callchain_entry_ctx ctx; int rctx, start_entry_idx; =20 + /* crosstask is not supported for user stacks */ + if (crosstask && user && !kernel) + return NULL; + entry =3D get_callchain_entry(&rctx); if (!entry) return NULL; @@ -240,7 +244,7 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, b= ool user, perf_callchain_kernel(&ctx, regs); } =20 - if (user) { + if (user && !crosstask) { if (!user_mode(regs)) { if (current->mm) regs =3D task_pt_regs(current); @@ -249,9 +253,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, b= ool user, } =20 if (regs) { - if (crosstask) - goto exit_put; - if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); =20 @@ -261,7 +262,6 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, b= ool user, } } =20 -exit_put: put_callchain_entry(rctx); =20 return entry; --=20 2.47.2 From nobody Mon Oct 6 19:10:52 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 3C8332FE32F; Thu, 17 Jul 2025 17:33:11 +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=1752773592; cv=none; b=KgkO8bi3UXKzElSLRhTi18iVOVRJyBGFsgz4zh+CavsywZ8hFP1Wr/4NUumt14c5ierZT27vcKrEo5PJG3WVZ2XtLgflyOHl0OphiaqH3bBogey1zxIyGKJIitlBRbjNSuCpQ1l43hHaSfll4wLHReIB/IdqgIL/dc+cUJjqKlU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773592; c=relaxed/simple; bh=zu7q7dulevcxsLQMsjcxfn6mbuHIR1BIFYpRfwZePWM=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ABFrTf+bLsQwxJEuclY+g6PF9TIxNV+M3ewArEhNbEPlKeYdnZuzDlzQ+kNHBhbDz3TjL9mJlpBIXfCE7BYh72d+JKMkulgUhYZlN7s20rSABRLNYc/477IGNn5nz4txmNDq9A9Ln/3+pB9QHqtIdEI4Lt5NLlvy0ow7GDy85Jw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Hist6LnB; 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="Hist6LnB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC085C4CEFC; Thu, 17 Jul 2025 17:33:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752773591; bh=zu7q7dulevcxsLQMsjcxfn6mbuHIR1BIFYpRfwZePWM=; h=Date:From:To:Cc:Subject:References:From; b=Hist6LnBxP8tJnU8MtSWx/BmPFhBvnz7ijLY+WL+/BCHXUIbyOIlcspDxYp7DqABX UuGQ2X2NDjipte9a3/JtcacMZ/yKuxWd02qnUy3aD1Ir6K27Dh8QAv8HZ5iKLJTvBu vYT4/ZciMQwia77zhJ7E6M+rm8wRcpt1mkkJJUBIMlxjzFOAEVukfguko3BAErHi4k 82x/D2OZZvRVga2tZhpS4/c5V9SBZmWqeaQd9iWHoTcu/R6w0n3SOYT9nl8hYfacyB oOZJStVRpU8V+j6wnu0cT17Cu08QmHUYO2jRd7dHdfMsr0Tv+lEthjnUctQs0c1C6V svg/7ZcerFdhw== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1ucSU9-00000006bzi-2b9Q; Thu, 17 Jul 2025 13:33:33 -0400 Message-ID: <20250717173333.468514575@kernel.org> User-Agent: quilt/0.68 Date: Thu, 17 Jul 2025 13:31:28 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Linus Torvalds , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Namhyung Kim , Alexei Starovoitov , Jens Axboe , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 3/5] perf: Use current->flags & PF_KTHREAD|PF_USER_WORKER instead of current->mm == NULL References: <20250717173125.434618999@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: Steven Rostedt To determine if a task is a kernel thread or not, it is more reliable to use (current->flags & (PF_KTHREAD|PF_USER_WORKERi)) than to rely on current->mm being NULL. That is because some kernel tasks (io_uring helpers) may have a mm field. Link: https://lore.kernel.org/linux-trace-kernel/20250424163607.GE18306@noi= sy.programming.kicks-ass.net/ Link: https://lore.kernel.org/all/20250624130744.602c5b5f@batman.local.home/ Signed-off-by: Steven Rostedt (Google) --- kernel/events/callchain.c | 6 +++--- kernel/events/core.c | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index cd0e3fc7ed05..5982d18f169b 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -246,10 +246,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel,= bool user, =20 if (user && !crosstask) { if (!user_mode(regs)) { - if (current->mm) - regs =3D task_pt_regs(current); - else + if (current->flags & (PF_KTHREAD | PF_USER_WORKER)) regs =3D NULL; + else + regs =3D task_pt_regs(current); } =20 if (regs) { diff --git a/kernel/events/core.c b/kernel/events/core.c index b2a53cabcb17..1fa554e2666d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7414,7 +7414,7 @@ static void perf_sample_regs_user(struct perf_regs *r= egs_user, if (user_mode(regs)) { regs_user->abi =3D perf_reg_abi(current); regs_user->regs =3D regs; - } else if (!(current->flags & PF_KTHREAD)) { + } else if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) { perf_get_regs_user(regs_user, regs); } else { regs_user->abi =3D PERF_SAMPLE_REGS_ABI_NONE; @@ -8054,7 +8054,7 @@ static u64 perf_virt_to_phys(u64 virt) * Try IRQ-safe get_user_page_fast_only first. * If failed, leave phys_addr as 0. */ - if (current->mm !=3D NULL) { + if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) { struct page *p; =20 pagefault_disable(); --=20 2.47.2 From nobody Mon Oct 6 19:10:52 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 5281F2FE367; Thu, 17 Jul 2025 17:33:12 +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=1752773592; cv=none; b=fJ2Da37zrpAo5NTtbj60RzgW+KOE/DJd4aKQpjYSaRZa6EMmK+VjfiLi71w0jVtwug6tHw+qM+QAE4jaSbFp0tI4fxxyLbVt7a+ExmIFqVupOXcGNq/SJylu4RgW9jxCfEqXhTFH0VoIdsNfGCVgMzzsykJhr42QxdZllicBvsA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773592; c=relaxed/simple; bh=mI3D1M5ZCCJZqFgS/KQwGydDItxmqMt6XzVMmgcg8Qs=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=UJOHriRM4WeTp3YEznvktMoyVg/KZiVO9/bqlWXZoDy1Y0Jn3mjGm8ubWv58Sha6j7H3K0gQ4sE1+/8F4TWmxpY41vqeUwTK29uMTQuAnHqqO05A5h4H5UIoZxk6WZAOEIQTi3N8qBc3VWieA8lvCgzAuJcjwRYo9apD1L+lu1Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r3OQv33z; 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="r3OQv33z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7D79C4CEFE; Thu, 17 Jul 2025 17:33:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752773592; bh=mI3D1M5ZCCJZqFgS/KQwGydDItxmqMt6XzVMmgcg8Qs=; h=Date:From:To:Cc:Subject:References:From; b=r3OQv33zG9EH3FJTIkc37C4sXROaoegHw4rTEoxf4eIAZWPJOZB6toEQ6dRBdgvnY kV4K+M9vUPjUDCnwydJTlZfdTXvtJJUzT5RneqBuuQ3cvEL23BM20Z3mtGuRfUwOmD 7tX4Dl40I8j9wMyMspd4Zx4ZLvPUkhKtZmJNXNofcaSIpdqCiXUpIx71lrMfc1BbM+ 55aSsN46pckorVCaefWkkTlIezyx9QMUBzi/s4G6XRVbbsrMmgXP0sYDZcOMZ9QOvt u3++mxjdupZaKfhACxndtULIj2dfRcSkm/jwJZ12jWavwDWpisBqPnezUBE5X3Jxzw qRcQR/Nd+tfvA== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1ucSU9-00000006c0C-3JSk; Thu, 17 Jul 2025 13:33:33 -0400 Message-ID: <20250717173333.639908993@kernel.org> User-Agent: quilt/0.68 Date: Thu, 17 Jul 2025 13:31:29 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Linus Torvalds , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Namhyung Kim , Alexei Starovoitov , Jens Axboe , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 4/5] perf: Simplify get_perf_callchain() user logic References: <20250717173125.434618999@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 Simplify the get_perf_callchain() user logic a bit. task_pt_regs() should never be NULL. Acked-by: Namhyung Kim Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- kernel/events/callchain.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 5982d18f169b..808c0d7a31fa 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -247,21 +247,19 @@ get_perf_callchain(struct pt_regs *regs, bool kernel,= bool user, if (user && !crosstask) { if (!user_mode(regs)) { if (current->flags & (PF_KTHREAD | PF_USER_WORKER)) - regs =3D NULL; - else - regs =3D task_pt_regs(current); + goto exit_put; + regs =3D task_pt_regs(current); } =20 - if (regs) { - if (add_mark) - perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); + if (add_mark) + perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); =20 - start_entry_idx =3D entry->nr; - perf_callchain_user(&ctx, regs); - fixup_uretprobe_trampoline_entries(entry, start_entry_idx); - } + start_entry_idx =3D entry->nr; + perf_callchain_user(&ctx, regs); + fixup_uretprobe_trampoline_entries(entry, start_entry_idx); } =20 +exit_put: put_callchain_entry(rctx); =20 return entry; --=20 2.47.2 From nobody Mon Oct 6 19:10:52 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 5F9A82FE368; Thu, 17 Jul 2025 17:33:12 +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=1752773592; cv=none; b=SNs8MkurAhHziLVJq7Y39EmNJGIkkAU8IbgQYSK0lCRW1Epdz1i0riwNNBBoY1pQFssS1fs9O1L74m9ZJUSKjKJTDgpzq64+uXsLwNcrfEfD25ZLT4+1l6ICw0fWxI8mNb3cRbpiRJNppytxckzy/R1iQZAtyFUiTmr/v2UlCnY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773592; c=relaxed/simple; bh=PrLV5/6t/jDNDZv13dJ+tk4FMXWbDNxrkHMrhIU764A=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=MgtXYVhczvQWIJBkv5rPWbVGF+dVUtw6fUsJMdUZYYe1WgdYbQgQ8zkxR3U7x7tpVgLLyEX+vu6ErE/9lz6YhKGFkr1S3PbkdyYDz9jIFrbKfxgg0VM1y4+fag7jme9SipSpvEHFJZ1ZnjL7ZHYBt1Wj/55xsyG5NEuIev0dPV4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QMhKkBQ7; 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="QMhKkBQ7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 304D5C4CEED; Thu, 17 Jul 2025 17:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752773592; bh=PrLV5/6t/jDNDZv13dJ+tk4FMXWbDNxrkHMrhIU764A=; h=Date:From:To:Cc:Subject:References:From; b=QMhKkBQ7wCz+KWRiWhE3QT9BE3z9z7zT19nsr/tl3qIoptT57DNxI/cR9wif+US7m UrPnsGfJHaa1wS2wMnrOAUzcP5q+9zd8XOzaeNVtI6SLQyn3sfflvwnXVBV6m8BOZx +euu2foBS8A9iSqNOw2wXF9eBikKJ5EwXLFwWyrei8tcmPa7VdUeoM54dNSXZVMLeU WsKju9WlzLqtDO3nWwO9e5KtFk3rveP/YCeqLU37yO3yEPLEyJiFj7fI0P0WeXrinv 0HwIzXcjPnOeu7lVmG5Pw26+HoC8eZaqkN/eSmDgbvt7BBcpQ3LgWwSJ/9yOQ7SpSN 7MG0EkL7+JLmg== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1ucSU9-00000006c0g-42Ag; Thu, 17 Jul 2025 13:33:33 -0400 Message-ID: <20250717173333.809101137@kernel.org> User-Agent: quilt/0.68 Date: Thu, 17 Jul 2025 13:31:30 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Linus Torvalds , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Namhyung Kim , Alexei Starovoitov , Jens Axboe , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 5/5] perf: Skip user unwind if the task is a kernel thread References: <20250717173125.434618999@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 If the task is not a user thread, there's no user stack to unwind. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- kernel/events/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 1fa554e2666d..bd0a33f389d2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8166,7 +8166,8 @@ struct perf_callchain_entry * perf_callchain(struct perf_event *event, struct pt_regs *regs) { bool kernel =3D !event->attr.exclude_callchain_kernel; - bool user =3D !event->attr.exclude_callchain_user; + bool user =3D !event->attr.exclude_callchain_user && + !(current->flags & (PF_KTHREAD | PF_USER_WORKER)); /* Disallow cross-task user callchains. */ bool crosstask =3D event->ctx->task && event->ctx->task !=3D current; const u32 max_stack =3D event->attr.sample_max_stack; --=20 2.47.2