From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f208.google.com (mail-oi1-f208.google.com [209.85.167.208]) (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 B9E323659FB for ; Fri, 19 Jun 2026 22:36:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.208 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781908594; cv=none; b=tDr0D7Y90kbuw6w5qKz6H9ZGUaHgtWfDJHLSX3WhMZnvh4zJNC06nWEd9tPMcLGWpVr0J3Pkmbm00/V47Hvd4aNpS6UkltwYC0rkLwXwATdCaRzUzxhoWAUcPdewKEGAaPlBPvSQH/nASK1xE50I0GvyMCSkAAfVq4cTLBAEmVE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781908594; c=relaxed/simple; bh=VY4XbAvhAEXf1JmEULohdcpMF3tyHo2xF2DcK++zE6c=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=dBmNEcOXPzGUDTqrJB47lSO2H6VVYN0jfqhIclR6zkG0QkGVc0CspddjJ7PZk9/5CJgaIPg7NONW7FfS+WIH2IepIe6ozLpYX1AzuNingDJnOqMJewo/Jl7R1YbD7bwUk41/x9VwGYFr1ENfInvrsQAX34vUfqE7sAkyx6y90Ls= 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=209.85.167.208 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-oi1-f208.google.com with SMTP id 5614622812f47-485ebc5706cso8374508b6e.0 for ; Fri, 19 Jun 2026 15:36:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781908589; x=1782513389; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=gP+LYeB38ctwzvmUsCsvE7at+Uu9aIFzTMPoFwYFcDg=; b=ll3BMkCjZ8kUnlnALrbQP6KjbhcO0REvv4rBos3nb+4CgKPdCnDOqJzNmcmgRTC+Kx ZAK1vZ8pWjz8PfH/+idNre8JyjZWLpq7qXChGS2TEary+yHBqiQidCAm+p3IUjplDV4h yDDQM6AI7hfRMz1+sbVjeJRFRqhupYGjBF1uBD2gTRNbxlXZSVBGfAS+T6D9Je7krrlh r1JDYa/2FtpoKfBevLmLb7XoAutp5YwY/2MS83ZkgoE5+bpingwkB64FKA2wCzZrdOKc 7N7jMIG3gagJ1vU15k5pm97PZwgA9rji3NixICNAx8bAQN4Z9KrOBXfGzHACDpDZ6B3X NxuQ== X-Forwarded-Encrypted: i=1; AFNElJ9ZryvVLXpvBQ34c2kZtwcPcx6K5+kVWTEXPMvLtKW+PnlO0Sh5NmLzgEUTb750Z3ZfvRnibizftltRg4s=@vger.kernel.org X-Gm-Message-State: AOJu0Ywh+ZQZCfZaCyXRbXP7LSf2c4FQou5s4GKUyC77Q4VVDDUwBK+S Zlpz3CZC/TqnN9ou69L8SHggIIOLCpkoygkp9PuW9Z+nETlD1GuV4JOEVc9mFFSTBWF3BsAiG9p fMVS8vZpC9vH5BaGMK/tQpBoi0So3Pdg8g/1vanus8/DSUT/HkWnIRUPRJKU= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1b1b:b0:69d:64a3:6320 with SMTP id 006d021491bc7-6a0d9fb7e87mr3215127eaf.6.1781908589414; Fri, 19 Jun 2026 15:36:29 -0700 (PDT) Date: Fri, 19 Jun 2026 15:36:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a35c46d.951a15ca.164930.0003.GAE@google.com> Subject: [syzbot] [mm?] KCSAN: data-race in __percpu_counter_limited_add / percpu_counter_add_batch (3) From: syzbot To: akpm@linux-foundation.org, baolin.wang@linux.alibaba.com, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 5e2e14749c3d Merge tag 'landlock-7.2-rc1' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=115453b6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b0ae27ce66b92956 dashboard link: https://syzkaller.appspot.com/bug?extid=a3c71b9db9c11c270f59 compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a565c60a4762/disk-5e2e1474.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e593a6eb0057/vmlinux-5e2e1474.xz kernel image: https://storage.googleapis.com/syzbot-assets/d24b55020ea3/bzImage-5e2e1474.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a3c71b9db9c11c270f59@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in __percpu_counter_limited_add / percpu_counter_add_batch read-write to 0xffff88812a80e9d0 of 8 bytes by task 11484 on cpu 0: percpu_counter_add_batch+0x101/0x120 lib/percpu_counter.c:107 percpu_counter_add include/linux/percpu_counter.h:71 [inline] percpu_counter_sub include/linux/percpu_counter.h:277 [inline] shmem_inode_unacct_blocks mm/shmem.c:263 [inline] shmem_recalc_inode+0x143/0x1f0 mm/shmem.c:466 shmem_undo_range+0xb20/0xb60 mm/shmem.c:1272 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x132/0x520 mm/shmem.c:1407 evict+0x2a5/0x510 fs/inode.c:828 iput_final fs/inode.c:2022 [inline] iput+0x430/0x5a0 fs/inode.c:2071 filename_unlinkat+0x21f/0x410 fs/namei.c:5585 __do_sys_unlink fs/namei.c:5616 [inline] __se_sys_unlink+0x2b/0xe0 fs/namei.c:5613 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5613 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88 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 0xffff88812a80e9d0 of 8 bytes by task 16836 on cpu 1: __percpu_counter_limited_add+0xc4/0x3f0 lib/percpu_counter.c:-1 percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline] shmem_inode_acct_blocks+0xf4/0x230 mm/shmem.c:232 shmem_alloc_and_add_folio mm/shmem.c:1979 [inline] shmem_get_folio_gfp+0x5d3/0xd90 mm/shmem.c:2502 shmem_get_folio mm/shmem.c:2608 [inline] shmem_write_begin+0xfc/0x1f0 mm/shmem.c:3239 generic_perform_write+0x186/0x490 mm/filemap.c:4363 shmem_file_write_iter+0xc5/0xf0 mm/shmem.c:3414 __kernel_write_iter+0x30f/0x590 fs/read_write.c:621 dump_emit_page fs/coredump.c:1298 [inline] dump_user_range+0xa73/0xd00 fs/coredump.c:1372 elf_core_dump+0x21c0/0x2340 fs/binfmt_elf.c:2109 coredump_write+0xaf9/0xdd0 fs/coredump.c:1052 do_coredump fs/coredump.c:1131 [inline] vfs_coredump+0x2770/0x3290 fs/coredump.c:1200 get_signal+0xd33/0xf10 kernel/signal.c:3023 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop kernel/entry/common.c:101 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline] irqentry_exit+0x14d/0x610 kernel/entry/common.c:165 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 value changed: 0x000000000000459f -> 0x00000000000035b4 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 16836 Comm: syz.5.4499 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ================================================================== --- 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