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KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (9)

Status: moderation: reported on 2024/09/09 18:07
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+ff4a3dac4bf8473e0615@syzkaller.appspotmail.com
First crash: 35d, last: 31d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range ext4 2 1801d 1803d 0/28 closed as invalid on 2019/11/19 14:44
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (7) exfat 1 951d 951d 0/28 auto-closed as invalid on 2022/04/13 08:14
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (6) ext4 1 1267d 1267d 0/28 auto-closed as invalid on 2021/06/01 07:24
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (8) ext4 exfat 2 639d 646d 0/28 auto-obsoleted due to no activity on 2023/04/01 19:00
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (5) exfat 2 1344d 1361d 0/28 auto-closed as invalid on 2021/03/15 14:17
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (3) ext4 2 1539d 1566d 0/28 auto-closed as invalid on 2020/09/02 05:07
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (2) ext4 2 1777d 1778d 0/28 auto-closed as invalid on 2020/02/12 06:26
upstream KCSAN: data-race in __writeback_single_inode / vfs_fsync_range (4) ext4 1 1499d 1499d 0/28 auto-closed as invalid on 2020/10/12 03:20

Sample crash report:
EXT4-fs: Quota format mount options ignored when QUOTA feature is enabled
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / vfs_fsync_range

read-write to 0xffff888112d3ea80 of 8 bytes by task 8751 on cpu 1:
 __writeback_single_inode+0x201/0x870 fs/fs-writeback.c:1687
 writeback_single_inode+0x12f/0x4a0 fs/fs-writeback.c:1772
 sync_inode_metadata+0x5c/0x90 fs/fs-writeback.c:2842
 generic_buffers_fsync_noflush+0xe4/0x130 fs/buffer.c:610
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x20b/0x6c0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x122/0x140 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2822 [inline]
 ext4_buffered_write_iter+0x338/0x380 fs/ext4/file.c:305
 ext4_file_write_iter+0x29f/0xe30
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888112d3ea80 of 8 bytes by task 8760 on cpu 0:
 vfs_fsync_range+0xa6/0x140 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2822 [inline]
 ext4_buffered_write_iter+0x338/0x380 fs/ext4/file.c:305
 ext4_file_write_iter+0x29f/0xe30
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000087 -> 0x0000000000000080

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8760 Comm: syz.1.1586 Not tainted 6.11.0-rc7-syzkaller-00097-g196145c606d0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/13 18:52 upstream 196145c606d0 b58f933c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __writeback_single_inode / vfs_fsync_range
2024/09/09 18:06 upstream da3ea35007d0 073f8be2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __writeback_single_inode / vfs_fsync_range
* Struck through repros no longer work on HEAD.