From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f205.google.com (mail-il1-f205.google.com [209.85.166.205]) (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 77B9B23D287 for ; Tue, 6 May 2025 07:52:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.205 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746517950; cv=none; b=INGM1aJfmxH6lrsTROmyTR18dpCpEgMwC+k+Uv9PfR3zBaD66ABYvyZjgUb8m87zWv+78TKmcGT7juzcUvU9sOxJ8q51t+wfTvrOzMzyK9CTQXPRhkAnA+VvhdBSt1oOqfNX87jkSB6UQXThZawup0b9YNh5tsCMm4Yb8SXv948= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746517950; c=relaxed/simple; bh=BtDyt2UFrNOoKlgcbIIR/8uenCycdB5p2V4g7UTDhX0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Oih6foWUGvECR2Kc6u5ENWo6Qgo+DfSehxRxPdJMnNJjaLdXxSxaJ4ByBr7xe5cjw7TVyUqJ29sVGZPDei7dpnwrK6KX2qxxUhGLlm2XXyk6V6Xz3IfMygZ2Gm2CaIV+2YfvaHFbaQbYCbDIrqUmK4Tu+mxpktTJ0HYvpMUkG7s= 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=209.85.166.205 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-il1-f205.google.com with SMTP id e9e14a558f8ab-3d817b17661so43885145ab.3 for ; Tue, 06 May 2025 00:52:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746517947; x=1747122747; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CKF1ErYQeMS2LAsXAlkKZC3QCEipg8mrCIYyD8W+Hdo=; b=YdEF83ylMDUljyRaouvWIVvQN+s/oVLXGNWCsL2tXR9ZEytx8fY0A565Ssot+Bv28l bSD/eH3lRHbCdIs21BdjK/7Ou6w3xfr9uw3jItKPg7V4l0d9rMybOwDt8u9Jx3R6Ccw6 m+B03bsMQYZcEJsUIDLdkw+Qsql5JoeEGBGPokSYqUkBdgdtZwmlvx0Mr2jImjJOIbSb LbrJaB/F+2PG+cJsXm3Eki5wIjmEwP+7SjTPgoOfJ+3IrVQYsv9GBSXa4mzxHFPgMLIJ bcwDHMMOzxo5JvP+R0n8B0rOFBHawBRtrcbF8NPdPGrQFWYbdgK6rV/IWBDTUut4OIWv vM1g== X-Forwarded-Encrypted: i=1; AJvYcCUh9odta7i3Szdxwy2v2l3Y8SPAGxDMbge6U9D+PeEldixSkfWA5n3Z3oNBUCdTaYe9lzKdoonFvMGlzwg=@vger.kernel.org X-Gm-Message-State: AOJu0YxPMhHCgG7JguWmwbC6TGc6ZBUM/bh0qZqsmcBTNUYG5YWbegII hJUIePN0SlRkqaFANk+VmceNs74Z4fe5WLsNWcKAN4k2SrB0pNpsRKcB3y1o/281wMYgEOZVeYk nec2pkFRxRCA86NeYQgMjAC1LXAg4pk1R4UXcfw8vLZes/8o8vH1QgEg= X-Google-Smtp-Source: AGHT+IEKLVR91TBPe4eYyoaPBkJZ4yi44af+i3Zdgo7jxVyxf1byGZoLu48pAoCPaxgkIaOevyJ5U2Ialqi6GP9177s4KEMNtzqM Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2588:b0:3d1:97dc:2f93 with SMTP id e9e14a558f8ab-3da5b349058mr103163835ab.20.1746517947459; Tue, 06 May 2025 00:52:27 -0700 (PDT) Date: Tue, 06 May 2025 00:52:27 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6819bfbb.050a0220.a19a9.0007.GAE@google.com> Subject: [syzbot] [mm?] KCSAN: data-race in copy_page_from_iter_atomic / pagecache_isize_extended 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: 01f95500a162 Merge tag 'uml-for-linux-6.15-rc6' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17abbb68580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6154604431d9aaf9 dashboard link: https://syzkaller.appspot.com/bug?extid=189d4742d07e937d68ea compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8d61c7d3421d/disk-01f95500.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d86d0377eab0/vmlinux-01f95500.xz kernel image: https://storage.googleapis.com/syzbot-assets/a6f455ac4fd5/bzImage-01f95500.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+189d4742d07e937d68ea@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in copy_page_from_iter_atomic / pagecache_isize_extended read to 0xffff88811d47e000 of 2048 bytes by task 37 on cpu 0: memcpy_from_iter lib/iov_iter.c:73 [inline] iterate_bvec include/linux/iov_iter.h:123 [inline] iterate_and_advance2 include/linux/iov_iter.h:304 [inline] iterate_and_advance include/linux/iov_iter.h:328 [inline] __copy_from_iter lib/iov_iter.c:249 [inline] copy_page_from_iter_atomic+0x77f/0xff0 lib/iov_iter.c:483 copy_folio_from_iter_atomic include/linux/uio.h:210 [inline] generic_perform_write+0x2c2/0x490 mm/filemap.c:4121 shmem_file_write_iter+0xc5/0xf0 mm/shmem.c:3464 lo_rw_aio+0x5f7/0x7c0 drivers/block/loop.c:-1 do_req_filebacked drivers/block/loop.c:-1 [inline] loop_handle_cmd drivers/block/loop.c:1866 [inline] loop_process_work+0x52d/0xa60 drivers/block/loop.c:1901 loop_workfn+0x31/0x40 drivers/block/loop.c:1925 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319 worker_thread+0x582/0x770 kernel/workqueue.c:3400 kthread+0x486/0x510 kernel/kthread.c:464 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 write to 0xffff88811d47e018 of 4072 bytes by task 4432 on cpu 1: zero_user_segments include/linux/highmem.h:278 [inline] folio_zero_segment include/linux/highmem.h:635 [inline] pagecache_isize_extended+0x26f/0x340 mm/truncate.c:850 ext4_alloc_file_blocks+0x4ad/0x720 fs/ext4/extents.c:4545 ext4_do_fallocate fs/ext4/extents.c:4694 [inline] ext4_fallocate+0x2b8/0x660 fs/ext4/extents.c:4750 vfs_fallocate+0x410/0x450 fs/open.c:338 ksys_fallocate fs/open.c:362 [inline] __do_sys_fallocate fs/open.c:367 [inline] __se_sys_fallocate fs/open.c:365 [inline] __x64_sys_fallocate+0x7a/0xd0 fs/open.c:365 x64_sys_call+0x2b88/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:286 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 4432 Comm: syz.8.11649 Not tainted 6.15.0-rc5-syzkaller-00022-g01f95500a162 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 ================================================================== --- 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