rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4362/1:b..l P5596/1:b..l
(detected by 0, t=10503 jiffies, g=20849, q=74 ncpus=2)
task:syz.2.201 state:R running task stack:26224 pid:5596 ppid:4277 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc900060c75a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 2446f5ff0441e200
RDX: 0000000000000000 RSI: ffffffff8a6c1780 RDI: ffffffff8abef920
RBP: ffffc900060c76c0 R08: dffffc0000000000 R09: fffffbfff2119049
R10: fffffbfff2119049 R11: 1ffffffff2119048 R12: 0000000000000000
R13: 1ffff92000c18ec0 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock include/linux/rcupdate.h:791 [inline]
percpu_ref_get_many+0x35/0x140 include/linux/percpu-refcount.h:202
percpu_ref_get include/linux/percpu-refcount.h:222 [inline]
css_get include/linux/cgroup.h:327 [inline]
charge_memcg+0x150/0x380 mm/memcontrol.c:6927
__mem_cgroup_charge+0x21/0x80 mm/memcontrol.c:6944
mem_cgroup_charge include/linux/memcontrol.h:672 [inline]
shmem_add_to_page_cache+0x8fc/0x1c00 mm/shmem.c:708
shmem_get_folio_gfp+0x158b/0x3400 mm/shmem.c:1971
shmem_get_folio mm/shmem.c:2072 [inline]
shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556
generic_perform_write+0x2f7/0x5a0 mm/filemap.c:3862
__generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f384398e1ff
RSP: 002b:00007f384477edf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f384398e1ff
RDX: 0000000001000000 RSI: 00007f38397f7000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009687
R10: 000020000001c302 R11: 0000000000000293 R12: 0000000000000004
R13: 00007f384477eef0 R14: 00007f384477eeb0 R15: 00007f38397f7000
task:kworker/u4:7 state:R running task stack:22560 pid:4362 ppid:2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_notrace+0xca/0x110 kernel/sched/core.c:6823
preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
rcu_is_watching+0x76/0xa0 kernel/rcu/tree.c:722
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0xe8/0x490 kernel/locking/lockdep.c:5633
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock include/linux/rcupdate.h:791 [inline]
batadv_nc_process_nc_paths+0xdb/0x390 net/batman-adv/network-coding.c:687
batadv_nc_worker+0x425/0x600 net/batman-adv/network-coding.c:728
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: rcu_preempt kthread starved for 10565 jiffies! g20849 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:26016 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5592 Comm: syz.1.200 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_cmp4+0x7e/0x80 kernel/kcov.c:288
Code: 8d 52 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 04 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 90 48 8b 04 24 65 48 8b 0d 84 8d 81 7e 65 8b 15 85 8d 81 7e 81
RSP: 0018:ffffc9000d627af0 EFLAGS: 00000097
RAX: ffffffff815048a4 RBX: 0000000000000011 RCX: 0000000000000002
RDX: ffff888026a80000 RSI: 0000000000000011 RDI: 0000000000000011
RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52001ac4f54 R11: 1ffff92001ac4f54 R12: ffff88807229fd20
R13: 1ffff11005adb7a9 R14: 0000000000000011 R15: ffff88802d6dbd38
FS: 00007f99359bd6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000002c0 CR3: 000000007c4b9000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
collect_signal kernel/signal.c:583 [inline]
__dequeue_signal+0x124/0x610 kernel/signal.c:624
dequeue_signal+0xe5/0x4b0 kernel/signal.c:647
get_signal+0x547/0x1350 kernel/signal.c:2751
arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9934b8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f99359bd0e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007f9934de5fa8 RCX: 00007f9934b8f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9934de5fa8
RBP: 00007f9934de5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9934de6038 R14: 00007ffe53715b60 R15: 00007ffe53715c48
vkms_vblank_simulate: vblank timer overrun