From d6c55b581ca723f777657823b0466d3544ff0c35 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 20 Aug 2025 14:03:43 -0400 Subject: [PATCH] perf: Skip user unwind if the task is a kernel thread [ Upstream commit 16ed389227651330879e17bd83d43bd234006722 ] 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) Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250820180428.930791978@kernel.org Signed-off-by: Sasha Levin --- 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 0339f60e3498..d6a86d8e9e59 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7847,7 +7847,8 @@ 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; -- 2.47.3