From: Steven Rostedt <rostedt@kernel.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org, x86@kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrii Nakryiko <andrii@kernel.org>,
Indu Bhagat <indu.bhagat@oracle.com>,
"Jose E. Marchesi" <jemarch@gnu.org>,
Beau Belgrave <beaub@linux.microsoft.com>,
Jens Remus <jremus@linux.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, Florian Weimer <fweimer@redhat.com>,
Sam James <sam@gentoo.org>
Subject: [PATCH v14 05/11] perf: Skip user unwind if the task is a kernel thread
Date: Fri, 18 Jul 2025 12:41:24 -0400 [thread overview]
Message-ID: <20250718164323.918565553@kernel.org> (raw)
In-Reply-To: 20250718164119.089692174@kernel.org
From: Josh Poimboeuf <jpoimboe@kernel.org>
If the task is not a user thread, there's no user stack to unwind.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
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 = !event->attr.exclude_callchain_kernel;
- bool user = !event->attr.exclude_callchain_user;
+ bool user = !event->attr.exclude_callchain_user &&
+ !(current->flags & (PF_KTHREAD | PF_USER_WORKER));
/* Disallow cross-task user callchains. */
bool crosstask = event->ctx->task && event->ctx->task != current;
const u32 max_stack = event->attr.sample_max_stack;
--
2.47.2
next prev parent reply other threads:[~2025-07-18 16:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-18 16:41 [PATCH v14 00/11] perf: Support the deferred unwinding infrastructure Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 01/11] perf: Remove get_perf_callchain() init_nr argument Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 02/11] perf: Have get_perf_callchain() return NULL if crosstask and user are set Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 03/11] perf: Use current->flags & PF_KTHREAD|PF_USER_WORKER instead of current->mm == NULL Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 04/11] perf: Simplify get_perf_callchain() user logic Steven Rostedt
2025-07-18 16:41 ` Steven Rostedt [this message]
2025-07-18 16:41 ` [PATCH v14 06/11] perf: Support deferred user callchains Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 07/11] perf: Support deferred user callchains for per CPU events Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 08/11] perf tools: Minimal CALLCHAIN_DEFERRED support Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 09/11] perf record: Enable defer_callchain for user callchains Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 10/11] perf script: Display PERF_RECORD_CALLCHAIN_DEFERRED Steven Rostedt
2025-07-18 16:41 ` [PATCH v14 11/11] perf tools: Merge deferred user callchains Steven Rostedt
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