syzbot


KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty (4)

Status: auto-closed as invalid on 2021/10/31 08:09
Subsystems: ext4
[Documentation on labels]
First crash: 942d, last: 942d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty ext4 4 1427d 1511d 0/26 closed as invalid on 2020/06/18 14:24
upstream KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty (2) ext4 35 1188d 1235d 0/26 auto-closed as invalid on 2021/02/27 09:33
upstream KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty (3) ext4 28 1064d 1132d 0/26 auto-closed as invalid on 2021/07/02 01:51

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty

write to 0xffff888105dcb05c of 2 bytes by task 1133 on cpu 0:
 ext4_ext_mark_initialized fs/ext4/ext4_extents.h:219 [inline]
 ext4_convert_unwritten_extents_endio fs/ext4/extents.c:3728 [inline]
 ext4_ext_handle_unwritten_extents+0x65f/0xa90 fs/ext4/extents.c:3861
 ext4_ext_map_blocks+0x777/0x1ff0 fs/ext4/extents.c:4131
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 ext4_convert_unwritten_extents+0x17a/0x2d0 fs/ext4/extents.c:4773
 ext4_convert_unwritten_io_end_vec+0xa4/0x130 fs/ext4/extents.c:4812
 ext4_end_io_end fs/ext4/page-io.c:184 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:257 [inline]
 ext4_end_io_rsv_work+0x198/0x360 fs/ext4/page-io.c:271
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff888105dcb05c of 4 bytes by task 10937 on cpu 1:
 ext4_do_update_inode fs/ext4/inode.c:5117 [inline]
 ext4_mark_iloc_dirty+0xd13/0x1700 fs/ext4/inode.c:5741
 __ext4_mark_inode_dirty+0x4ec/0x5c0 fs/ext4/inode.c:5937
 ext4_dirty_inode+0x86/0xa0 fs/ext4/inode.c:5966
 __mark_inode_dirty+0x77/0x6a0 fs/fs-writeback.c:2398
 mark_inode_dirty include/linux/fs.h:2452 [inline]
 generic_write_end+0x157/0x180 fs/buffer.c:2202
 ext4_da_write_end+0x59b/0x730 fs/ext4/inode.c:3116
 generic_perform_write+0x251/0x3e0 mm/filemap.c:3781
 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x7bc/0x900 fs/read_write.c:594
 ksys_write+0xd9/0x190 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:656
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000083ff -> 0x00000585

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10937 Comm: syz-executor.2 Tainted: G        W         5.15.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/09/26 08:00 upstream a3b397b4fffb 8cac236e .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in ext4_ext_handle_unwritten_extents / ext4_mark_iloc_dirty
* Struck through repros no longer work on HEAD.