KCSAN: data-race in __lru_add_drain_all / folio_add_lru

Status: moderation: reported on 2021/12/14 17:42
Subsystems: mm
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+d676f4fcc6452f55d1d0@syzkaller.appspotmail.com
First crash: 1734d, last: 1h31m
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
65407472 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ KCSAN: data-race in __lru_add_drain_all / folio_add_lru 2026/05/26 14:11 2026/05/26 14:11 2026/05/26 14:32 76d4b4b1

			
		
6f19202b 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 305c0ec5

			
		
3876cab2 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 a9d6a792
LLM did not call tool to set outputs

Sample crash report:
EXT4-fs: Ignoring removed orlov option
EXT4-fs: Ignoring removed orlov option
EXT4-fs: inline encryption not supported
EXT4-fs (loop6): can't mount with data=, fs mounted w/o journal
==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / folio_add_lru

read-write to 0xffff888237c26528 of 1 bytes by task 2446 on cpu 0:
 folio_batch_add include/linux/folio_batch.h:77 [inline]
 __folio_batch_add_and_move mm/swap.c:229 [inline]
 folio_add_lru+0xa4/0x250 mm/swap.c:562
 folio_add_lru_vma+0x49/0x70 mm/swap.c:581
 wp_page_copy mm/memory.c:3943 [inline]
 do_wp_page+0x13a5/0x2030 mm/memory.c:4336
 handle_pte_fault mm/memory.c:6395 [inline]
 __handle_mm_fault mm/memory.c:6517 [inline]
 handle_mm_fault+0x8bc/0x2da0 mm/memory.c:6686
 do_user_addr_fault+0x634/0x1060 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

read to 0xffff888237c26528 of 1 bytes by task 2409 on cpu 1:
 folio_batch_count include/linux/folio_batch.h:56 [inline]
 cpu_needs_drain mm/swap.c:831 [inline]
 __lru_add_drain_all+0x17e/0x450 mm/swap.c:928
 lru_add_drain_all+0x10/0x20 mm/swap.c:944
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 __ext4_fill_super fs/ext4/super.c:5803 [inline]
 ext4_fill_super+0x2c8c/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1640
 get_tree_bdev+0x1f/0x30 fs/super.c:1663
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3841
 path_mount+0x4ad/0xb90 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4367
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4367
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x06 -> 0x08

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2409 Comm: syz.6.8130 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================

Crashes (2012):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/02 12:33 upstream 2d2338c93da7 e611ffe1 .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
2026/08/01 18:29 upstream 02dc699f83d0 e611ffe1 .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
2026/08/01 07:31 upstream 0131b508c0e2 e611ffe1 .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
2026/07/31 21:56 upstream 8ba098e6b6ff 7664cf44 .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
2026/07/31 12:06 upstream 8ba098e6b6ff aaffb173 .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
2026/07/30 23:00 upstream 3708dd948844 aaffb173 .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
2026/07/30 12:59 upstream 11028ab62899 2377cd3d .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
2026/07/30 02:08 upstream fc46aed51f62 6ef5c1e2 .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
2026/07/29 10:16 upstream fc02acf6ac0c 19622d9d .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
2026/07/28 22:49 upstream 3b5f4b83c4ab edc8a875 .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
2026/07/28 03:55 upstream 62cc90241548 45ae1df4 .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
2026/07/27 05:03 upstream 4235cb24ec1e 492bab15 .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
2026/07/26 07:22 upstream 3dab139d4795 492bab15 .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
2026/07/26 05:38 upstream 0ce37745d4bf 492bab15 .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
2026/07/25 20:00 upstream 0ce37745d4bf 492bab15 .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
2026/07/25 08:21 upstream e2a936998ab2 492bab15 .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
2026/07/25 01:48 upstream 48a5a7ab8d6a 492bab15 .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
2026/07/24 19:39 upstream 48a5a7ab8d6a dd737a83 .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
2026/07/24 12:06 upstream d326f83e819c 544adce9 .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
2026/07/24 00:07 upstream d326f83e819c 71a13572 .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
2026/07/23 15:53 upstream 4539944e5151 71a13572 .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
2026/07/23 01:06 upstream 4539944e5151 881ce5c2 .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
2026/07/22 16:11 upstream 248951ddc14d 4a865b71 .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
2026/07/22 05:04 upstream 248951ddc14d b561ce9c .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
2026/07/21 21:01 upstream 248951ddc14d 7c5de9c3 .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
2026/07/21 11:08 upstream b95f03f04d47 7c5de9c3 .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
2026/07/21 04:22 upstream b95f03f04d47 de6a700d .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
2026/07/20 15:40 upstream 1590cf032971 de6a700d .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
2026/07/20 02:32 upstream 82a47586c0b9 72524a66 .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
2026/07/19 09:38 upstream c6859eed755d 72524a66 .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
2026/07/18 20:31 upstream 1229e2e57a5c 72524a66 .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
2026/07/18 08:26 upstream 94515f3a7d42 72524a66 .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
2026/07/17 19:35 upstream 111e7b23e5b0 8aaff637 .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
2026/07/17 02:05 upstream fce2dfa773ce 71b49442 .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
2026/07/16 16:00 upstream 37e2f878a7a6 71b49442 .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
2026/07/16 08:46 upstream 37e2f878a7a6 27a8bd60 .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
2026/07/16 05:13 upstream 58717b2a1365 27a8bd60 .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
2026/07/15 12:35 upstream 58717b2a1365 a4ed0f4f .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
2026/07/14 06:51 upstream 3b029c035b34 2130f682 .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
2026/07/13 11:29 upstream a13c140cc289 d78ea535 .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
2026/07/13 01:20 upstream f4fb100039e9 d78ea535 .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
2026/07/11 19:23 upstream dd3210c47e8d d78ea535 .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
2026/05/26 13:07 upstream e8c2f9fdadee a3e47276 .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.