From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f79.google.com (mail-ot1-f79.google.com [209.85.210.79]) (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 4B44F286881 for ; Sun, 9 Aug 2026 05:29:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786253368; cv=none; b=rTBr/Lo+Z+zTcRZOBM7otV9pfRFawh+nVHp9R4cDyl+TY7jC3pnUNVKJ8LbxNgEsccK2hAPJ44lmXvV5ad4yNfE08WsYRH4qgfXDtDkcNO5n0uU5e79pxF4K/rizBc693xP8e34uHXh64h36yKFT7b8HwH69jIYoFYuxvkSBmu4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786253368; c=relaxed/simple; bh=X9OQpKpuomPd2DHH4c9UycInQYjg3rZQ1z/4rBiDkto=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=nrvFjFTMSnlshMha5hjDrMOm9nZg+CMfD8lraQvjIejCASKF05WonEC/zblwZ2fK362JT/CGZRZYU+nybE5crgVWSRo42oeF1SQuzdWxk2pSqDme80SuP3F93t+tqT91WaDtn+ZpkzLceD7I3n/TLwbVR0lP0CsJilCI92xQsCY= 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=209.85.210.79 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-ot1-f79.google.com with SMTP id 46e09a7af769-7e9e741693bso479197a34.0 for ; Sat, 08 Aug 2026 22:29:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786253366; x=1786858166; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=nJCEcOBoCOvBwJ00UyGRPpiB5DkjriR63z9d68ArgeY=; b=P/oYciyG8SeTwjA4tzHKr0do4CxRWEV+Mp6AdvwCdnfZSkGYi716+OCIEWjFle4/bJ tTLlxdnlbf4xd8t7P4Lgx3h48rJ/uug4okKLFNvBwQ/hfCdvld+PEyprBsRMpGeqJ/2U r3XzXzUlw9mUut0JyyM8sTNCoRFv/cyFszshJRQ0uemGmGob+768nZaniJtD/4K+kOqz 73/qNOr5H46jbRHpFFejTMP+UWsH5B1GmfBATwFXMp6p4u+nW9D8JP0PCf8iNfx3kaHA JOrPYljbYmHYlYvPype6yTkoVsThKBxIYeN0h323dUncCrt4nVRa6p7hG8Wvd+a5RXnT Cx6Q== X-Forwarded-Encrypted: i=1; AHgh+RoKOgGKpOnhjkmsWTFQMEJX0g2VZUMaQFohcVpF7nvJOo6mCCbBhbHemc/68HtQQxZdwI1jHmg3gN24Ha6uDx37hjA=@vger.kernel.org X-Gm-Message-State: AOJu0YxUGuP3BLkVHvtWamhxVdVBj84m54wwtSILMXtcqA26CDFPX9aT 0xC5gx371NFPajASJyU5bUAVRD1roduhSWspYw09cxvpdGhHEsljdSEQL+jkXy4m952/FUJrAEH DzyhpLauIdwCl6YtC4C5AZZWtihXtSNQg0asOJmN+CnlRxtMNDjrqlRhCRWE= Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2015:b0:6ae:42c7:ef88 with SMTP id 006d021491bc7-6ae96c17639mr18161767eaf.7.1786253366198; Sat, 08 Aug 2026 22:29:26 -0700 (PDT) Date: Sat, 08 Aug 2026 22:29:26 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a781036.9c11d2ce.289b96.00c7.GAE@google.com> Subject: [syzbot] [trace?] KCSAN: data-race in __rb_reserve_next / ring_buffer_iter_peek From: syzbot To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rostedt@goodmis.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: f9a2394a2348 Merge tag 'mm-hotfixes-stable-2026-08-06-18-4.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14ba2132580000 kernel config: https://syzkaller.appspot.com/x/.config?x=84b3039e8461eef5 dashboard link: https://syzkaller.appspot.com/bug?extid=b57601b220ccc4fa1551 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/82bd4b0b2828/disk-f9a2394a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ab3cb0b1997d/vmlinux-f9a2394a.xz kernel image: https://storage.googleapis.com/syzbot-assets/b0a8ddb2683a/bzImage-f9a2394a.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b57601b220ccc4fa1551@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in __rb_reserve_next / ring_buffer_iter_peek write to 0xffff8881331f4000 of 8 bytes by task 12741 on cpu 0: __rb_reserve_next+0x5f1/0x6c0 kernel/trace/ring_buffer.c:4851 rb_reserve_next_event kernel/trace/ring_buffer.c:4925 [inline] ring_buffer_lock_reserve+0x68c/0x830 kernel/trace/ring_buffer.c:4984 __trace_buffer_lock_reserve kernel/trace/trace.h:1676 [inline] trace_event_buffer_lock_reserve+0x148/0x300 kernel/trace/trace.c:1924 trace_event_buffer_reserve+0x120/0x180 kernel/trace/trace_events.c:688 do_trace_event_raw_event_kmem_cache_free include/trace/events/kmem.h:117 [inline] trace_event_raw_event_kmem_cache_free+0xa4/0x140 include/trace/events/kmem.h:117 __do_trace_kmem_cache_free include/trace/events/kmem.h:117 [inline] trace_kmem_cache_free include/trace/events/kmem.h:117 [inline] kmem_cache_free+0x31d/0x380 mm/slub.c:6503 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x1b8/0x360 mm/rmap.c:514 free_pgtables+0x50e/0x630 mm/memory.c:414 exit_mmap+0x367/0x5e0 mm/mmap.c:1312 __mmput+0x28/0x1c0 kernel/fork.c:1187 mmput+0x40/0x50 kernel/fork.c:1210 exec_mm_put_old fs/exec.c:916 [inline] setup_new_exec+0x20a/0x230 fs/exec.c:1353 load_elf_binary+0x77a/0x1a30 fs/binfmt_elf.c:1024 search_binary_handler fs/exec.c:1694 [inline] exec_binprm fs/exec.c:1726 [inline] bprm_execve+0x45c/0x9b0 fs/exec.c:1778 do_execveat_common+0x7a4/0x8a0 fs/exec.c:1876 __do_sys_execve fs/exec.c:1949 [inline] __se_sys_execve fs/exec.c:1943 [inline] __x64_sys_execve+0x5f/0x80 fs/exec.c:1943 x64_sys_call+0x2752/0x3020 arch/x86/include/generated/asm/syscalls_64.h:60 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8881331f4000 of 8 bytes by task 11658 on cpu 1: ring_buffer_iter_empty kernel/trace/ring_buffer.c:5647 [inline] rb_iter_peek kernel/trace/ring_buffer.c:6143 [inline] ring_buffer_iter_peek+0x265/0xb10 kernel/trace/ring_buffer.c:6305 peek_next_entry kernel/trace/trace.c:2349 [inline] __find_next_entry+0x1a9/0x420 kernel/trace/trace.c:2398 trace_find_next_entry_inc kernel/trace/trace.c:2672 [inline] s_next+0x10e/0x370 kernel/trace/trace.c:2711 traverse+0x1c1/0x3b0 fs/seq_file.c:121 seq_read_iter+0x7dc/0x8f0 fs/seq_file.c:196 do_iter_readv_writev+0x4f6/0x5a0 fs/read_write.c:-1 vfs_readv+0x1e8/0x6d0 fs/read_write.c:1019 do_preadv fs/read_write.c:1133 [inline] __do_sys_preadv2 fs/read_write.c:1192 [inline] __se_sys_preadv2+0xfc/0x1c0 fs/read_write.c:1183 __x64_sys_preadv2+0x67/0x80 fs/read_write.c:1183 x64_sys_call+0x2b3b/0x3020 arch/x86/include/generated/asm/syscalls_64.h:328 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x000001502ab37190 -> 0x000001505958442b Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 11658 Comm: syz.6.11885 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 ================================================================== --- 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