From mboxrd@z Thu Jan 1 00:00:00 1970 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 078CC25C70D; Fri, 25 Apr 2025 14:56:16 +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=1745592976; cv=none; b=lgZL9mtWdaPPBgjRGoyIMec7Bbl/fqSv8nNkAap1vcnmgiFH9OwE1y2Hh4DeuGuj7BShRjOOixOKTPkSaHeMnqe4AJ9HEtpHL1CqYNhefa+jiI+//Wxv0NVdZp3OyBakfVTkO9gC5HQb4G6I0SJWBX8gBXmGyOqwsvDkIgtAdq0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745592976; c=relaxed/simple; bh=hqAtq1MhKKdean7S2Puxw7kvv69CFkdFWsJeIcbXdHw=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=Un4jJ6G6guaQzgDZr8ZhaUsv2P4vV6kJXsGdKF4QzpnFkuz5eAQjhtrkXbuDa9eEGLGPcN9DOD+6yA0Kf8T7rTSALv8GNXZ4VOzvV/f31mrkr+mlw0V9LNWsL2uKuOaw9W1l8d/TSm+6YSbMIdTXbZ/RRriKHSqLEjFN77+oc1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D06EBC4CEED; Fri, 25 Apr 2025 14:56:15 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1u8KVK-0000000HSmP-02rV; Fri, 25 Apr 2025 10:58:14 -0400 Message-ID: <20250425145813.862449275@goodmis.org> User-Agent: quilt/0.68 Date: Fri, 25 Apr 2025 10:54:35 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Josh Poimboeuf , x86@kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Indu Bhagat , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , linux-perf-users@vger.kernel.org, Mark Brown , linux-toolchains@vger.kernel.org, Jordan Rome , Sam James , Andrii Nakryiko , Jens Remus , Florian Weimer , Andy Lutomirski , Weinan Liu , Blake Jones , Beau Belgrave , "Jose E. Marchesi" , Alexander Aring Subject: [PATCH v6 13/18] perf: Skip user unwind if the task is a kernel thread. References: <20250425145422.132820147@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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) --- Changes since v5: https://lore.kernel.org/20250424162633.216110813@goodmis.org - Use current->flags & PF_KTHREAD instead of current->mm == NULL. (Peter Zijlstra) 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 430dd158b1ee..ec9edf602974 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8101,7 +8101,8 @@ 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); /* 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