From nobody Fri Dec 19 07:50:25 2025 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 8A2A528A1F9; Thu, 24 Apr 2025 16:24:37 +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=1745511877; cv=none; b=WPwHiXK1iIwvswuiCEP8oqRMXoyse0FtciG+vfLU8KCRvSMN3c9V8eeE1HM/Pd4LpnoxLvqXm6PoFXT5SejVvSJ0RYpm+DCoDeW53Y8AEg9bS5qawkqgE4AToL5OuC1UX4MH8/zp/yGlJS4AZ6qc9cqf4t8jh/BASRTItEtJjNA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745511877; c=relaxed/simple; bh=FOpCcB0SHYp4WJdk6l5JxGOtcrrVvxc0E7NzipAYfug=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=HPWrFscD0U/5mDukqjDes5rekac+aRIebk6mKTtgp4+5C51jBuyjyGFtiRf3Yb/1QEluuZJ3sM0jreTVjd7h1BTW9eFU5DsC5DRxhNn93uAcCGj62bprzxJFSJf92+tbLHazZMzaYgvlzSGpe7QdQlvpevyxs5wddiIqGNUwuxU= 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 6C0EBC4CEFC; Thu, 24 Apr 2025 16:24:37 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1u7zPF-0000000GybA-1XiL; Thu, 24 Apr 2025 12:26:33 -0400 Message-ID: <20250424162633.216110813@goodmis.org> User-Agent: quilt/0.68 Date: Thu, 24 Apr 2025 12:25:41 -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" Subject: [PATCH v5 12/17] perf: Skip user unwind if !current->mm References: <20250424162529.686762589@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf If the task doesn't have any memory, there's no stack to unwind. Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- Note from v4: https://lore.kernel.org/all/24cde1381495cd637f0d5663ab7629572= bc0eca6.1737511963.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 =3D !event->attr.exclude_callchain_kernel; - bool user =3D !event->attr.exclude_callchain_user; + bool user =3D !event->attr.exclude_callchain_user && current->mm; /* Disallow cross-task user callchains. */ bool crosstask =3D event->ctx->task && event->ctx->task !=3D current; const u32 max_stack =3D event->attr.sample_max_stack; --=20 2.47.2