From f5712e929c0fe3a8db2cf21d688b292a6fa7cda7 Mon Sep 17 00:00:00 2001 Message-ID: In-Reply-To: <7f56d9ee24976d45babdc3856c85d47df2ae8a13.1752857321.git.sam@gentoo.org> References: <7f56d9ee24976d45babdc3856c85d47df2ae8a13.1752857321.git.sam@gentoo.org> From: Josh Poimboeuf Date: Fri, 18 Jul 2025 12:41:24 -0400 Subject: [PATCH 17/34] perf: Skip user unwind if the task is a kernel thread 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 f6c9ba1cffeaf..2572cb8f01fba 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; -- 2.50.1