[PATCH v5 12/17] perf: Skip user unwind if !current->mm
Steven Rostedt <[email protected]> Thu, 24 Apr 2025 12:25:41 -0400
| Newsgroups | org.kernel.vger.linux-toolchains,org.kernel.vger.linux-kernel,org.kernel.vger.linux-perf-users,org.kernel.vger.linux-trace-kernel |
|---|---|
| Message-ID | <[email protected]> |
From: Josh Poimboeuf <[email protected]> If the task doesn't have any memory, there's no stack to unwind. Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Steven Rostedt (Google) <[email protected]> --- Note from v4: https://lore.kernel.org/all/24cde1381495cd637f0d5663ab7629572bc0eca6.1737511963.git.jpoimboe@kernel.org/ - From the previous version, Peter Zijlstra brought up concern about io_uring helpers, but this was never resolved. No update was made. kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 009f34bd9e63..40b98b05fb7c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8101,7 +8101,7 @@ 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->mm; /* 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