syzbot


INFO: rcu detected stall in blkdev_write_iter

Status: auto-obsoleted due to no activity on 2025/07/23 16:46
Subsystems: cgroups mm block
[Documentation on labels]
First crash: 223d, last: 101d

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P28526/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=184621, q=746 ncpus=1)
task:syz.0.4702      state:R  running task     stack:27496 pid:28526 tgid:28519 ppid:17874  task_flags:0x400040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5870
Code: 66 0e 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 92 bf ee 0e 0f 82 74 02 00 00 8b 35 0a ef ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 69 66 0e 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc9000af9f230 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3bf440 RCX: 00000000ef9d33e4
RDX: 0000000000000000 RSI: ffffffff8dbc43ac RDI: ffffffff8bf44f80
RBP: 0000000000000002 R08: 0ac0d5affe09d4ff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4161 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4217
 alloc_buffer_head+0x21/0x160 fs/buffer.c:2997
 folio_alloc_buffers+0x2bd/0x830 fs/buffer.c:924
 create_empty_buffers+0x36/0x480 fs/buffer.c:1662
 folio_create_buffers+0x109/0x150 fs/buffer.c:1773
 __block_write_begin_int+0x320/0x16d0 fs/buffer.c:2097
 iomap_write_begin+0x5de/0x1680 fs/iomap/buffered-io.c:825
 iomap_write_iter fs/iomap/buffered-io.c:952 [inline]
 iomap_file_buffered_write+0x43b/0xcb0 fs/iomap/buffered-io.c:1033
 blkdev_buffered_write block/fops.c:690 [inline]
 blkdev_write_iter+0x57d/0xdf0 block/fops.c:749
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x5ba/0x1180 fs/read_write.c:684
 ksys_write+0x12a/0x240 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60df98e969
RSP: 002b:00007f60e0866038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f60dfbb6080 RCX: 00007f60df98e969
RDX: 00000000fffffdef RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f60dfa10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f60dfbb6080 R15: 00007ffe7993cf78
 </TASK>
rcu: rcu_preempt kthread starved for 250 jiffies! g184621 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27704 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 3403 Comm: kworker/R-bat_e Not tainted 6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: bat_events batadv_tt_purge
RIP: 0010:debug_smp_processor_id+0xb/0x20 lib/smp_processor_id.c:60
Code: 65 ff 0d e8 f3 36 08 e9 40 ff ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 c7 c6 00 4f f4 8b <48> c7 c7 40 4f f4 8b e9 f9 fe ff ff 66 0f 1f 84 00 00 00 00 00 90
RSP: 0018:ffffc90000a08870 EFLAGS: 00000246
RAX: ffff888060171080 RBX: 0000000000000001 RCX: ffffffff8a30e2b7
RDX: 1ffff1100c02e213 RSI: ffffffff8bf44f00 RDI: ffff888060171098
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff92000141130
R13: 0000000000000001 R14: ffff88805008e000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888124abf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bfd5c2ad88 CR3: 000000007e8da000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 ip6t_do_table+0x2a2/0x1be0 net/ipv6/netfilter/ip6_tables.c:283
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626
 nf_hook.constprop.0+0x422/0x750 include/linux/netfilter.h:269
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ipv6_rcv+0xa4/0x680 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:5887
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6000
 process_backlog+0x442/0x15e0 net/core/dev.c:6352
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0xa97/0x1010 net/core/dev.c:7510
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 do_softirq kernel/softirq.c:480 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:467
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_tt_local_purge+0x21c/0x3c0 net/batman-adv/translation-table.c:1315
 batadv_tt_purge+0x8b/0xb80 net/batman-adv/translation-table.c:3509
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 rescuer_thread+0x620/0xea0 kernel/workqueue.c:3496
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 14610 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
net_ratelimit: 14745 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:f1:c5:d8:63:aa, vlan:0)

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/24 16:44 upstream a79be02bba5c 9c80ffa0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in blkdev_write_iter
2025/03/02 03:10 upstream 03d38806a902 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in blkdev_write_iter
2024/12/23 03:33 upstream bcde95ce32b6 b4fbdbd4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in blkdev_write_iter
* Struck through repros no longer work on HEAD.