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: 1977d, last: 6h58m
▶ ▼ ✨ 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 1977d 2278d 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:
==================================================================
BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88811a1d16b8 of 8 bytes by interrupt on cpu 1:
 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
 bh_end_async_write+0x18b/0x230 fs/buffer.c:430
 bio_endio+0x390/0x570 block/bio.c:1908
 blk_update_request+0x33a/0x710 block/blk-mq.c:1036
 scsi_end_request+0x4b/0x4c0 drivers/scsi/scsi_lib.c:671
 scsi_io_completion+0x7f/0x1d0 drivers/scsi/scsi_lib.c:1125
 scsi_finish_command+0x1c7/0x1e0 drivers/scsi/scsi.c:198
 scsi_complete+0x12c/0x4a0 drivers/scsi/scsi_lib.c:1604
 blk_complete_reqs block/blk-mq.c:1242 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1247
 handle_softirqs+0x109/0x310 kernel/softirq.c:669
 __do_softirq kernel/softirq.c:703 [inline]
 invoke_softirq kernel/softirq.c:542 [inline]
 __irq_exit_rcu+0x40/0xf0 kernel/softirq.c:786
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x37/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674

read to 0xffff88811a1d16b8 of 8 bytes by task 9639 on cpu 0:
 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_write_and_wait_range+0x1f5/0x370 mm/filemap.c:692
 filemap_invalidate_pages+0xd3/0x1e0 mm/filemap.c:2946
 kiocb_invalidate_pages+0x6e/0x80 mm/filemap.c:2965
 blkdev_direct_write+0x30/0x100 block/fops.c:704
 blkdev_write_iter+0x3c5/0x520 block/fops.c:797
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57a/0x990 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0xffffffffffffff80 -> 0xfffffffffffffe00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9639 Comm: syz.8.1279 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
==================================================================

Crashes (5644):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/05 13:55 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/11/04 03:16 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __xa_clear_mark / xas_find_marked
2026/11/03 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.