From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7ACE23168E1 for ; Fri, 6 Feb 2026 07:36:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770363393; cv=none; b=qh/6JJBSB5/Ysj5Cj34yR7xAc695Pvp75pagqPsMyq81hdafrjcLs0egAMvPKlylszKVQ8jtjqPQcfRlANQXTTI2KTFyf18nNZt/6mIDw9riaNaVVUhJXRrbRlsfnMav8aM/983K+i/6+kx4WU7zTBSJkFRgiNcTqLNP0yD6qTk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770363393; c=relaxed/simple; bh=9FRWCuPiMkkrQ972rVMHLpsSw40yJDZ9OtQpWKj04rY=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Ynq8AC/btcvr+4TEQbnZWgj54eTiS8+GyStNG8n1CpkXXJwlyXVUkgueM8xyVaoMEBbnrPKh+Y9/OeHs/GKbtQIZnJqKHiycn5E1mICOuczDAcaD7PgfHDjw6HexnGc0TGlA+ndq7ch772Q+orLl6bS7q0dcb3qkInsyjYoKSDE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f77.google.com with SMTP id 006d021491bc7-66b560fcc42so7611262eaf.0 for ; Thu, 05 Feb 2026 23:36:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770363392; x=1770968192; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=rHyQDbOdo3dmXSaHfpXFy2nfDGyjWyiBXjkHRyFU+9w=; b=MkAWx6ssje+hczxqEgwBCN2d/NbQUphnVd4ct7QTHYBt0uIbllkRU8RjHPDjeCoxX1 jWNAV+1lEtpSpddCpuhStwCVZzQ+W4gUTMgQ3G5eh44aGZwXnw7fzk+7mhFcyYDU27hS qrkXYVc9j11m6zXHjQXXB8V0AwJumgiGBUSVk8FIw3rs6dDZLVFYoe6edJvQY8sedACi du7Rs4v3ilP4rcOj7kuflkFczQXhtFLLSLzerc+Wyl6AyS2ua/nTcqIIqYIy/mvY5Lc2 /VaRxBUppAz8OWPZaT0Hjnuvjk3uF85P+7es49cRSMj6LPa0EcRM++nBQwTYtdqduqao qBcA== X-Forwarded-Encrypted: i=1; AJvYcCVTt0fTM6g7Lxwb7Pavwr2sAi8wxTDVaScHuA8uDZFY47PrPdlPRO7zlP9YBtI0Y94ue5aP1IQ4BI3bvYD1+0KI@vger.kernel.org X-Gm-Message-State: AOJu0YziZhPEuzBVNSNrCtTamhZeMGFNMfrm870G4s/dz7i/CFIW9e9G RtDalN9jtyws7Rsg7jXrJ/4oxZGCCIxNT+6m+4AbGekb/g4gIMlOpLWNTzbNjXSMg1l4J9q05tF xclD+FY0VB+poEurqdvMeYLaKF+1uVWUvVjG95XM9NFcgzYui/lvimlQHfcY= Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4610:b0:663:1f2:3e1f with SMTP id 006d021491bc7-66d32fdc188mr597246eaf.32.1770363392486; Thu, 05 Feb 2026 23:36:32 -0800 (PST) Date: Thu, 05 Feb 2026 23:36:32 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69859a00.a00a0220.34fa92.0028.GAE@google.com> Subject: [syzbot] [perf?] KCSAN: data-race in perf_event_set_state / perf_mmap_rb From: syzbot To: acme@kernel.org, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, irogers@google.com, james.clark@linaro.org, jolsa@kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c537e12daeec Merge tag 'bpf-fixes' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1133a5fc580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c160236e1ef1e401 dashboard link: https://syzkaller.appspot.com/bug?extid=5334e6bdc43f6d1dcb7d compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/036ac5d12a14/disk-c537e12d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/07ddd15f46f8/vmlinux-c537e12d.xz kernel image: https://storage.googleapis.com/syzbot-assets/7866e67b7a58/bzImage-c537e12d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5334e6bdc43f6d1dcb7d@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in perf_event_set_state / perf_mmap_rb write to 0xffff88812279f1a0 of 8 bytes by task 12011 on cpu 1: perf_event_update_time kernel/events/core.c:737 [inline] perf_mmap_rb+0x71c/0x910 kernel/events/core.c:7037 perf_mmap+0x1ce/0x2f0 kernel/events/core.c:7164 vfs_mmap include/linux/fs.h:2053 [inline] mmap_file mm/internal.h:167 [inline] __mmap_new_file_vma mm/vma.c:2421 [inline] __mmap_new_vma mm/vma.c:2484 [inline] __mmap_region mm/vma.c:2708 [inline] mmap_region+0x1045/0x1410 mm/vma.c:2786 do_mmap+0x9b3/0xbe0 mm/mmap.c:558 vm_mmap_pgoff+0x17a/0x2e0 mm/util.c:581 ksys_mmap_pgoff+0x268/0x310 mm/mmap.c:604 x64_sys_call+0x16bb/0x3000 arch/x86/include/generated/asm/syscalls_64.h:10 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88812279f1a0 of 8 bytes by task 12005 on cpu 0: __perf_update_times kernel/events/core.c:720 [inline] perf_event_update_time kernel/events/core.c:735 [inline] perf_event_set_state+0x153/0x440 kernel/events/core.c:754 event_sched_out+0x2d4/0x4d0 kernel/events/core.c:2391 group_sched_out kernel/events/core.c:2415 [inline] __pmu_ctx_sched_out+0x3e7/0x530 kernel/events/core.c:3458 ctx_sched_out+0x273/0x2d0 kernel/events/core.c:3539 task_ctx_sched_out+0x4d/0x70 kernel/events/core.c:2859 perf_event_context_sched_out kernel/events/core.c:3746 [inline] __perf_event_task_sched_out+0x286/0x370 kernel/events/core.c:3846 perf_event_task_sched_out include/linux/perf_event.h:1654 [inline] prepare_task_switch kernel/sched/core.c:5045 [inline] context_switch kernel/sched/core.c:5201 [inline] __schedule+0xbf0/0xcd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x5f/0xd0 kernel/sched/core.c:6960 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x4ff/0xe20 kernel/locking/mutex.c:776 __mutex_lock_slowpath+0xa/0x10 kernel/locking/mutex.c:1065 mutex_lock+0x89/0x90 kernel/locking/mutex.c:290 perf_poll+0x180/0x1f0 kernel/events/core.c:6150 vfs_poll include/linux/poll.h:82 [inline] select_poll_one fs/select.c:480 [inline] do_select+0x8f1/0xf40 fs/select.c:536 core_sys_select+0x3dc/0x6e0 fs/select.c:677 do_pselect fs/select.c:759 [inline] __do_sys_pselect6 fs/select.c:798 [inline] __se_sys_pselect6+0x213/0x280 fs/select.c:789 __x64_sys_pselect6+0x78/0x90 fs/select.c:789 x64_sys_call+0x2e98/0x3000 arch/x86/include/generated/asm/syscalls_64.h:271 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x000000000038c145 -> 0x00000000003929d3 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 12005 Comm: syz.4.2772 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup