KCSAN: data-race in __xa_clear_mark / xas_find_marked (2)

Status: moderation: reported on 2021/06/26 18:58
Subsystems: fs mm
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+03743c59b799c7b55cd4@syzkaller.appspotmail.com
First crash: 1974d, last: 4h28m
▶ ▼ ✨ AI Jobs (6)
ID Workflow Result Correct Bug Created Started Finished Revision
105cf64d repro-c Reproduced: ✅ ❓ KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/09/28 19:13 2026/09/28 19:13 2026/09/28 19:23 58f15308
5ddf1a8e assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/05/31 20:53 2026/05/31 20:53 2026/05/31 21:09 6b4a8443
72fecced assessment-security 💥 KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/05/15 06:56 2026/05/15 06:56 2026/05/15 06:57 6ccb967e
a0741bf4 repro ❓ KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/03/07 06:26 2026/03/07 06:26 2026/03/07 06:28 31e9c887
be28beee assessment-kcsan Benign: ✅ Confident: ✅ ❓ KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/02/24 18:46 2026/02/24 18:46 2026/02/24 18:48 305c0ec5
f2b43e1e assessment-kcsan 💥 KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) 2026/01/09 22:47 2026/01/09 22:47 2026/01/09 23:06 75199160
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __xa_clear_mark / xas_find_marked fs mm 6 558 1975d 2276d 0/29 closed as invalid on 2021/06/07 13:50
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/09/29 05:47 21m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 72d3fcf802c45d00b300f25b848a93c3a2bd7c7e report job log log

Sample crash report:
EXT4-fs (sda1): shut down requested (0)
==================================================================
BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff888106f1fb48 of 8 bytes by task 53 on cpu 0:
 instrument_read_write include/linux/instrumented.h:56 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark lib/xarray.c:922 [inline]
 __xa_clear_mark+0xf5/0x1e0 lib/xarray.c:2103
 __folio_end_writeback+0xe7/0x530 mm/page-writeback.c:2965
 folio_end_writeback_no_dropbehind+0x6d/0x200 mm/filemap.c:1671
 folio_end_writeback+0x72/0x110 mm/filemap.c:1710
 ext4_finish_bio+0x454/0x770 fs/ext4/page-io.c:140
 ext4_release_io_end+0x9f/0x1f0 fs/ext4/page-io.c:154
 ext4_end_io_end+0x18d/0x240 fs/ext4/page-io.c:205
 ext4_do_flush_completed_IO fs/ext4/page-io.c:285 [inline]
 ext4_end_io_rsv_work+0x15b/0x1f0 fs/ext4/page-io.c:300
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0x53f/0xa20 kernel/workqueue.c:3578
 worker_thread+0x56c/0x770 kernel/workqueue.c:3659
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888106f1fb48 of 8 bytes by task 3540 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x211/0x650 lib/xarray.c:1513
 find_get_entry mm/filemap.c:2105 [inline]
 filemap_get_folios_tag+0xf7/0x400 mm/filemap.c:2371
 __filemap_fdatawait_range mm/filemap.c:523 [inline]
 filemap_fdatawait_keep_errors+0x6c/0x190 mm/filemap.c:626
 wait_sb_inodes fs/fs-writeback.c:2942 [inline]
 sync_inodes_sb+0x42a/0x4d0 fs/fs-writeback.c:3075
 sync_filesystem+0x108/0x190 fs/sync.c:64
 freeze_super+0x398/0xa60 fs/super.c:2249
 fs_super_freeze fs/super.c:1452 [inline]
 fs_bdev_freeze+0x168/0x2d0 fs/super.c:1530
 bdev_freeze+0xf3/0x1a0 block/bdev.c:318
 ext4_force_shutdown+0x190/0x2f0 fs/ext4/ioctl.c:826
 ext4_ioctl_shutdown fs/ext4/ioctl.c:868 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1888 [inline]
 ext4_ioctl+0x16f8/0x3210 fs/ext4/ioctl.c:1932
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x239d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffffe0000000 -> 0xfffff80000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3540 Comm: syz.2.10 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
==================================================================
syz.2.10 (3540) used greatest stack depth: 10928 bytes left

Crashes (5642):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/03 12:35 upstream 6628e7d4c6b2 e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/11/02 10:38 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/11/01 15:51 upstream cbbddb6b08cc 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/30 18:46 upstream bd5c762ac051 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/30 17:31 upstream d89e1d186ec9 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/30 08:59 upstream d89e1d186ec9 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/29 20:09 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/29 14:11 upstream c339f4010dea b1d00f76 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/28 14:55 upstream 65ba8f34ec88 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/28 02:24 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/27 11:40 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/26 16:44 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/26 06:51 upstream 390febb5805d 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/25 20:12 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/25 04:59 upstream 6fba331225f5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/24 11:30 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/24 00:21 upstream 734bef548a96 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/23 16:42 upstream a1c2b1da93f5 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/22 21:37 upstream 7be4bc52fd9e b55fad29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/21 21:30 upstream a804c5742bff 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/21 06:40 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/20 11:18 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/19 15:06 upstream c03c1a14507d 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/17 19:10 upstream 58161ead29e5 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/17 11:13 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/16 13:28 upstream 2f2f7eeef8b0 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/15 21:57 upstream 9aa622dbaab8 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/15 14:19 upstream 0fcb05b72344 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/14 12:41 upstream 4056b3c9d3c9 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/14 04:06 upstream ca3e345926b0 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/13 11:30 upstream 24a19b953e2a 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/12 16:41 upstream 24a19b953e2a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/12 05:54 upstream 24a19b953e2a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/11 18:44 upstream b88c841d1164 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/11 07:42 upstream a5ebb76233b7 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/10 22:57 upstream 3857c2fe5449 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/10 02:24 upstream fc1c25014ff8 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/09 21:21 upstream af32da41b032 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/09 08:59 upstream af32da41b032 b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/08 04:47 upstream 7b63ef2d55f2 4f6a9fcf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/08 03:11 upstream 7b63ef2d55f2 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/07 12:51 upstream 602042bf29f6 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/10/06 18:44 upstream 69f80fef3153 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/09/29 01:27 upstream 72d3fcf802c4 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/09/28 09:11 upstream 72d3fcf802c4 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/05/31 13:28 upstream 174914ea5513 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/05/14 17:50 upstream 66182ca873a4 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/03/07 00:29 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/02/24 10:41 upstream 7dff99b35460 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/01/09 20:12 upstream 372800cb95a3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2021/06/26 05:21 upstream b7050b242430 9d2ab5df .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2021/06/22 18:45 upstream 0c18f29aae7c aba2b2fb .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2021/06/07 18:41 upstream 614124bea77e b718257f .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
* Struck through repros no longer work on HEAD.