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INFO: rcu detected stall in sys_fdatasync (2)

Status: auto-obsoleted due to no activity on 2026/06/19 15:08
Subsystems: block
Labels: prio:normal
[Documentation on labels]
First crash: 105d, last: 92d
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
1e4bc919-9480-4ee6-9cc6-8d0da32403ea assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: rcu detected stall in sys_fdatasync (2) 2026/05/31 19:21 2026/05/31 19:21 2026/05/31 21:41 6b4a844333e83556da95d61d7f207e7ef5cd4bc6

			
		
298ce467-1c23-40a1-b54f-21240527696b assessment-security 💥 INFO: rcu detected stall in sys_fdatasync (2) 2026/05/15 06:18 2026/05/15 06:18 2026/05/15 06:19 6ccb967e465e832a7bfd7a116ad00d52a0923a5d
failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128
From /app/workdir/repo/linux
 * branch                HEAD       -> FETCH_HEAD
Updating files:  ...
truncated to first 200 bytes; open job for full error
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_fdatasync modules 1 1 209d 209d 0/29 auto-obsoleted due to no activity on 2026/02/22 10:38

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9556/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=45541, q=1900 ncpus=1)
task:syz.2.670       state:R  running task     stack:27520 pid:9556  tgid:9551  ppid:5826   task_flags:0x20400040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x19e/0x320 kernel/locking/lockdep.c:5893
Code: ff 65 0f c1 05 cb 4f 29 12 83 f8 01 0f 85 3d 01 00 00 9c 58 f6 c4 02 0f 85 28 01 00 00 41 f7 c6 00 02 00 00 0f 85 de 00 00 00 <48> 8b 44 24 10 65 48 2b 05 1d 08 29 12 0f 85 63 01 00 00 48 83 c4
RSP: 0018:ffffc90004caf338 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e7e7660 RCX: ffffc90004caf344
RDX: 0000000000000000 RSI: ffffffff8de5a1bd RDI: ffffffff8c1b0aa0
RBP: ffffffff81b7b2fe R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 00000000000167f9 R12: ffff888029e6bd00
R13: ffffc90004caf3f0 R14: 0000000000000202 R15: 0000000000000001
 rcu_lock_release include/linux/rcupdate.h:322 [inline]
 rcu_read_unlock include/linux/rcupdate.h:881 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x3c3/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4873
 mempool_alloc_noprof+0x1b7/0x310 mm/mempool.c:566
 bio_alloc_bioset+0x392/0x850 block/bio.c:598
 bio_alloc include/linux/bio.h:368 [inline]
 submit_bh_wbc+0x250/0x770 fs/buffer.c:2801
 __block_write_full_folio+0x77f/0xee0 fs/buffer.c:1930
 block_write_full_folio+0x3b5/0x4e0 fs/buffer.c:2750
 blkdev_writepages+0xc7/0x150 block/fops.c:486
 do_writepages+0x278/0x600 mm/page-writeback.c:2554
 filemap_writeback+0x22d/0x2e0 mm/filemap.c:387
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 file_write_and_wait_range+0xcd/0x140 mm/filemap.c:786
 blkdev_fsync+0x6c/0xd0 block/fops.c:619
 vfs_fsync_range fs/sync.c:186 [inline]
 vfs_fsync fs/sync.c:200 [inline]
 do_fsync+0xbf/0x220 fs/sync.c:211
 __do_sys_fdatasync fs/sync.c:221 [inline]
 __se_sys_fdatasync fs/sync.c:219 [inline]
 __x64_sys_fdatasync+0x35/0x50 fs/sync.c:219
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcd6659c799
RSP: 002b:00007fcd67432028 EFLAGS: 00000246 ORIG_RAX: 000000000000004b
RAX: ffffffffffffffda RBX: 00007fcd66816270 RCX: 00007fcd6659c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fcd66632c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcd66816308 R14: 00007fcd66816270 R15: 00007ffc202bf618
 </TASK>
net_ratelimit: 8246 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 9090 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:6b:f6:99:b6:df, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/21 14:57 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_fdatasync
2026/03/08 16:11 upstream c23719abc330 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_fdatasync
* Struck through repros no longer work on HEAD.