syzbot


KCSAN: data-race in __lru_add_drain_all / folio_add_lru

Status: moderation: reported on 2021/12/14 17:42
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+d676f4fcc6452f55d1d0@syzkaller.appspotmail.com
First crash: 1665d, last: 6h22m
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
6f19202b-e9ba-4367-8611-b919c37d4f90 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in __lru_add_drain_all / folio_add_lru 2026/02/25 03:53 2026/02/25 03:53 2026/02/25 03:55 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
3876cab2-c7da-4e1d-b950-186fea7fcefb assessment-kcsan 💥 KCSAN: data-race in __lru_add_drain_all / folio_add_lru 2026/01/15 23:52 2026/01/15 23:52 2026/01/15 23:53 a9d6a79219801d2130df3b1a792c57f0e5428e9f LLM did not call tool to set outputs

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / folio_add_lru

read-write to 0xffff888237c266e8 of 1 bytes by task 14845 on cpu 0:
 folio_batch_add include/linux/folio_batch.h:77 [inline]
 __folio_batch_add_and_move mm/swap.c:194 [inline]
 folio_add_lru+0xaa/0x1f0 mm/swap.c:517
 folio_add_lru_vma+0x49/0x70 mm/swap.c:536
 wp_page_copy mm/memory.c:3943 [inline]
 do_wp_page+0x13b1/0x2040 mm/memory.c:4336
 handle_pte_fault mm/memory.c:6443 [inline]
 __handle_mm_fault mm/memory.c:6565 [inline]
 handle_mm_fault+0x8bb/0x2e70 mm/memory.c:6734
 do_user_addr_fault+0x62f/0x1050 arch/x86/mm/fault.c:1334
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff888237c266e8 of 1 bytes by task 3304 on cpu 1:
 folio_batch_count include/linux/folio_batch.h:56 [inline]
 cpu_needs_drain mm/swap.c:786 [inline]
 __lru_add_drain_all+0x17e/0x450 mm/swap.c:883
 lru_add_drain_all+0x10/0x20 mm/swap.c:899
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x610/0x7b0 fs/ext4/super.c:1355
 generic_shutdown_super+0xee/0x220 fs/super.c:646
 kill_block_super+0x2a/0x70 fs/super.c:1725
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7492
 deactivate_locked_super+0x75/0x1c0 fs/super.c:476
 deactivate_super+0x97/0xa0 fs/super.c:509
 cleanup_mnt+0x2bb/0x330 fs/namespace.c:1312
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1319
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x211/0x820 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x02 -> 0x04

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3304 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (1890):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/25 10:18 upstream e7ae89a0c97c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/25 01:02 upstream 6a97c4d5262d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/24 10:33 upstream 4cbfe4502e3d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/23 12:17 upstream 79bd2dded182 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/22 20:46 upstream 45255ea1ca09 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/22 05:50 upstream 6779b50faa56 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/21 18:06 upstream 758c807bb943 e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/21 09:30 upstream 8bc67e4db64a 41b8c833 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/19 16:45 upstream ab5fce87a778 223544dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/18 14:59 upstream 5200f5f493f7 55156e84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/16 21:40 upstream 6916d5703ddf de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/16 12:26 upstream d458a240344c a15a64a6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/15 21:57 upstream d458a240344c 81fb92f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/15 12:45 upstream 70eda68668d1 9cd3beaa .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/15 07:07 upstream 70eda68668d1 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/15 03:41 upstream 66182ca873a4 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/13 22:27 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/12 23:28 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/12 13:42 upstream 50897c955902 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/11 22:59 upstream 5d6919055dec d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/11 08:46 upstream 5d6919055dec 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/11 01:19 upstream 5d6919055dec 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/10 11:27 upstream 1bfaee9d3351 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/10 05:11 upstream e92b2872d0b1 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/09 16:42 upstream 27a26ccfd528 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/08 08:00 upstream fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/07 14:15 upstream 8ab992f815d6 cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/07 05:39 upstream 5862221fdded f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/06 00:55 upstream 9207d47f966b 26da2c66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/05 12:13 upstream a293ec25d59d 06e69a27 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/04 21:41 upstream c7e4e4d5f7dc a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/04 10:40 upstream 6d35786de281 85f1bcf2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/04 00:26 upstream f377d0025eb0 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/02 08:25 upstream f1a5e78a55eb a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/01 19:26 upstream 6fe0be6dc7fa 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/05/01 15:16 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/30 18:20 upstream e75a43c7cec4 a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/30 13:04 upstream e75a43c7cec4 a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/30 00:24 upstream 57b8e2d666a3 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/29 18:43 upstream 57b8e2d666a3 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/28 20:43 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/27 11:26 upstream 254f49634ee1 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/27 00:10 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/25 17:09 upstream 897d54018cc9 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/25 02:40 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/24 13:09 upstream dd6c438c3e64 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/24 05:34 upstream 45dcf5e28813 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/22 12:08 upstream 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/21 18:35 upstream 4ee64205ffaa 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/21 16:39 upstream b4e07588e743 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/04/21 04:51 upstream b4e07588e743 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/03/10 12:54 upstream 1f318b96cc84 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/02/24 11:13 upstream 7dff99b35460 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2026/01/15 11:52 upstream 944aacb68baf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2021/12/14 16:36 upstream 5472f14a3742 d018dd31 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
2021/11/02 13:42 upstream bfc484fe6abb 098b5d53 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __lru_add_drain_all / folio_add_lru
* Struck through repros no longer work on HEAD.