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KCSAN: data-race in redirty_tail_locked / vfs_fsync_range (2)

Status: upstream: reported on 2024/09/09 19:00
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+a388a53633c9a4e9b22e@syzkaller.appspotmail.com
First crash: 35d, last: 26d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] KCSAN: data-race in redirty_tail_locked / vfs_fsync_range (2) 0 (1) 2024/09/09 19:00
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in redirty_tail_locked / vfs_fsync_range ext4 1 149d 149d 0/28 auto-obsoleted due to no activity on 2024/06/23 01:00

Sample crash report:
==================================================================
BUG: KCSAN: data-race in redirty_tail_locked / vfs_fsync_range

read-write to 0xffff888106aa1860 of 4 bytes by task 9346 on cpu 1:
 redirty_tail_locked+0x54/0x270 fs/fs-writeback.c:1351
 writeback_single_inode+0x221/0x3f0 fs/fs-writeback.c:1799
 sync_inode_metadata+0x5c/0x90 fs/fs-writeback.c:2849
 generic_buffers_fsync_noflush+0xd8/0x120 fs/buffer.c:610
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ff/0x6c0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x116/0x130 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2870 [inline]
 ext4_buffered_write_iter+0x326/0x370 fs/ext4/file.c:305
 ext4_file_write_iter+0x293/0xe10
 iter_file_splice_write+0x5f1/0x980 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x160/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x302/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x39b/0x970 fs/read_write.c:1388
 __do_sys_sendfile64 fs/read_write.c:1455 [inline]
 __se_sys_sendfile64 fs/read_write.c:1441 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1441
 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 0xffff888106aa1860 of 4 bytes by task 9359 on cpu 0:
 vfs_fsync_range+0x9a/0x130 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2870 [inline]
 ext4_buffered_write_iter+0x326/0x370 fs/ext4/file.c:305
 ext4_file_write_iter+0x293/0xe10
 iter_file_splice_write+0x5f1/0x980 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x160/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x302/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x39b/0x970 fs/read_write.c:1388
 __do_sys_sendfile64 fs/read_write.c:1455 [inline]
 __se_sys_sendfile64 fs/read_write.c:1441 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1441
 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: 0x0000003a -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9359 Comm: syz.0.1932 Tainted: G        W          6.11.0-syzkaller-05319-g4a39ac5b7d62 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/19 04:53 upstream 4a39ac5b7d62 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in redirty_tail_locked / vfs_fsync_range
2024/09/14 09:44 upstream b7718454f937 c7e35043 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in redirty_tail_locked / vfs_fsync_range
2024/09/09 18:10 upstream da3ea35007d0 073f8be2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in redirty_tail_locked / vfs_fsync_range
* Struck through repros no longer work on HEAD.