From nobody Tue Oct 7 21:42:00 2025 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) (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 E93FE8462; Sat, 5 Jul 2025 14:43:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.181.97.72 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751726640; cv=none; b=VnTXkH+sV/MAcdJ7I5iK9ffGZOQmigw4voHl6hSCZ5OdDYBv9wAPImz5jvtJrnyMJVvBtG5QSts35LeA+Mo3AJeC+Br2q6mpwU1TJ2Ka6heOLUJ04C83lLae8P9ydSETtYWx2SYMR8ZpEmyVWVZEy5G+sdBrueOT/5QEiLUo2gg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751726640; c=relaxed/simple; bh=YI//x8ls7R+pdx9z7vF4GczOnOwBb1p1eyUMgVpi8i0=; h=Message-ID:Date:MIME-Version:Subject:From:To:References: In-Reply-To:Content-Type; b=YyF74y1LtMbqb3albBvwb+TNkkIEAzmslE+s/YxCZePFgKwkToY1UPASvS7oZa+RH95DouHYTTCuqYB0iJgAHFiSPu/KHjFzHVX8zxKRZ5SO0aXm/Y/ZhBQCkJT6NEgUOSkr05vnhYn1dSZ/4EUCl/SoIcmRozIsVtcl4NiDCRE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp; arc=none smtp.client-ip=202.181.97.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=I-love.SAKURA.ne.jp Received: from www262.sakura.ne.jp (localhost [127.0.0.1]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 565EhcLa057270; Sat, 5 Jul 2025 23:43:38 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 565Ehcke057266 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Sat, 5 Jul 2025 23:43:38 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: Date: Sat, 5 Jul 2025 23:43:37 +0900 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH] perf/core: Fix WARN in perf_sigtrap() From: Tetsuo Handa To: syzbot , Peter Zijlstra , linux-perf-users@vger.kernel.org, LKML References: <685af60a.a00a0220.2e5631.0092.GAE@google.com> Content-Language: en-US In-Reply-To: Content-Transfer-Encoding: quoted-printable X-Anti-Virus-Server: fsav104.rs.sakura.ne.jp X-Virus-Status: clean Content-Type: text/plain; charset="utf-8" Since commit 4f6fc7821283 ("perf: Fix sample vs do_exit()") has moved perf_event_exit_task() call from after exit_task_work() to before exit_task_work(), task_work_add() from perf_event_exit_task() now returns 0 than -ESRCH, despite perf_event_exit_task_context() updates ctx->task to TASK_TOMBSTONE. As a result, event->ctx->task =3D=3D current assumption no longer holds. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=3D2fe61cb2a86066be6985 Fixes: 4f6fc7821283 ("perf: Fix sample vs do_exit()") Signed-off-by: Tetsuo Handa Reported-by: syzbot+2fe61cb2a86066be6985@syzkaller.appspotmail.com Tested-by: syzbot+2fe61cb2a86066be6985@syzkaller.appspotmail.com --- #syz test 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 7281230044d0..489f42defe3c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7208,7 +7208,8 @@ static void perf_sigtrap(struct perf_event *event) * ctx->task or current has changed in the meantime. This can be the * case on architectures that do not implement arch_irq_work_raise(). */ - if (WARN_ON_ONCE(event->ctx->task !=3D current)) + if (WARN_ON_ONCE(event->ctx->task !=3D current && + event->ctx->task !=3D TASK_TOMBSTONE)) return; =20 /* --=20 2.50.0