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KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked

Status: auto-obsoleted due to no activity on 2024/10/25 03:23
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+df649ff02864b5d5fe27@syzkaller.appspotmail.com
First crash: 135d, last: 92d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked (2) ext4 5 1d20h 33d 0/28 moderation: reported on 2024/11/18 06:29

Sample crash report:
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
EXT4-fs error (device loop4): ext4_xattr_ibody_find:2240: inode #15: comm syz.4.264: corrupted in-inode xattr: ea_inode specified without ea_inode feature enabled
==================================================================
BUG: KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked

read-write to 0xffff888106ef5ce8 of 4 bytes by task 4309 on cpu 0:
 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 0xffff888106ef5ce8 of 4 bytes by task 4307 on cpu 1:
 generic_buffers_fsync_noflush+0x83/0x120 fs/buffer.c:605
 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

value changed: 0x0000003a -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4307 Comm: syz.4.264 Not tainted 6.11.0-syzkaller-07337-g2004cef11ea0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/20 03:22 upstream 2004cef11ea0 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
2024/09/12 11:32 upstream 77f587896757 60e1a995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
2024/09/08 05:26 upstream d1f2d51b711a 9750182a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
2024/09/03 10:36 upstream 67784a74e258 326f9c5a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
2024/08/31 10:13 upstream 1934261d8974 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
2024/08/08 03:12 upstream 6a0e38264012 de12cf65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_buffers_fsync_noflush / redirty_tail_locked
* Struck through repros no longer work on HEAD.