KCSAN: data-race in __filemap_add_folio / sync

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
040c7118-d1de-4f98-a290-c9508017d932	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in __filemap_add_folio / sync_bdevs (4)	2026/07/02 00:03	2026/07/02 00:03	2026/07/02 00:15	93f579545ae410f5bccfa141d2e7bf03178f036c
1348866a-9532-46e8-9822-2678c5cb1f3d	assessment-kcsan	Benign: ✅	❓	KCSAN: data-race in __filemap_add_folio / sync_bdevs (4)	2026/06/30 05:14	2026/06/30 05:14	2026/06/30 05:33	fff8d0a0e302881e84edbe2230016e3bec252ec6

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __filemap_add_folio / sync_bdevs (3) ext4 prio:low	6	2	89d	130d	0/29	auto-obsoleted due to no activity on 2026/06/01 01:25
upstream	KCSAN: data-race in __filemap_add_folio / sync_bdevs fs mm	6	1	1256d	1256d	0/29	auto-obsoleted due to no activity on 2023/04/05 16:41
upstream	KCSAN: data-race in __filemap_add_folio / sync_bdevs (2) ext4	6	1	651d	651d	0/29	auto-obsoleted due to no activity on 2024/10/26 07:57

Kernel

Title

Rank 🛈

upstream

KCSAN: data-race in __filemap_add_folio / sync_bdevs (3) ext4 prio:low

89d

130d

0/29

auto-obsoleted due to no activity on 2026/06/01 01:25

upstream

KCSAN: data-race in __filemap_add_folio / sync_bdevs fs mm

1256d

0/29

auto-obsoleted due to no activity on 2023/04/05 16:41

upstream

KCSAN: data-race in __filemap_add_folio / sync_bdevs (2) ext4

651d

0/29

auto-obsoleted due to no activity on 2024/10/26 07:57

================================================================== BUG: KCSAN: data-race in __filemap_add_folio / sync_bdevs read-write to 0xffff8881005f7178 of 8 bytes by task 2946 on cpu 0: __filemap_add_folio+0x66e/0x880 mm/filemap.c:919 filemap_add_folio+0x1d3/0x350 mm/filemap.c:966 __filemap_get_folio_mpol+0x32e/0x840 mm/filemap.c:2022 __filemap_get_folio include/linux/pagemap.h:761 [inline] grow_dev_folio fs/buffer.c:960 [inline] grow_buffers fs/buffer.c:1026 [inline] __getblk_slow fs/buffer.c:1044 [inline] bdev_getblk+0x170/0x3c0 fs/buffer.c:1439 __getblk include/linux/buffer_head.h:382 [inline] jbd2_journal_get_descriptor_buffer+0xce/0x210 fs/jbd2/journal.c:974 jbd2_journal_commit_transaction+0xc41/0x3260 fs/jbd2/commit.c:636 kjournald2+0x211/0x3d0 fs/jbd2/journal.c:199 kthread+0x221/0x270 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 0xffff8881005f7178 of 8 bytes by task 14789 on cpu 1: sync_bdevs+0xd3/0x260 block/bdev.c:1278 ksys_sync fs/sync.c:105 [inline] __ia32_sys_sync+0x81/0xb0 fs/sync.c:111 x64_sys_call+0x2f3a/0x3020 arch/x86/include/generated/asm/syscalls_64.h:163 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: 0x0000000000000523 -> 0x0000000000000524 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 14789 Comm: syz.9.10116 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/06/30 05:14	upstream	dc59e4fea9d8	fff8d0a0	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __filemap_add_folio / sync_bdevs

Crashes (1):

Assets (help?)