INFO: task syz.3.1486:12963 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1486 state:D stack:25000 pid:12963 tgid:12954 ppid:5839 task_flags:0x400140 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
sync_bdevs+0x1ac/0x340 block/bdev.c:1288
ksys_sync+0xb9/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5cb76eebe9
RSP: 002b:00007f5cb5935038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f5cb7926090 RCX: 00007f5cb76eebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5cb7926090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5cb7926128 R14: 00007f5cb7926090 R15: 00007fff1da21798
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
17 locks held by irq/33-virtio1-/1188:
5 locks held by kworker/u8:10/1510:
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900059efbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900059efbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8ecc6280 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658
#3: ffff8880344f40d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff8880344f40d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff8880344f40d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506
#4: ffff8880344f1300 (&devlink->lock_key#34){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff8880344f1300 (&devlink->lock_key#34){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff8880344f1300 (&devlink->lock_key#34){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506
2 locks held by kworker/u8:11/1558:
2 locks held by getty/5599:
#0: ffff88823bf480a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5827:
3 locks held by kworker/0:3/10385:
1 lock held by udevd/12720:
#0: ffff888024d834c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:945
1 lock held by udevd/12722:
#0: ffff888024ddf4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:945
1 lock held by syz.3.1486/12963:
#0: ffff888024ddf4c8 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
7 locks held by syz-executor/13501:
#0: ffff88801111e488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3108 [inline]
#0: ffff88801111e488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff88803cd61878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325
#2: ffff888026b12878 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326
#3: ffffffff8e542998 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x12c/0x6f0 drivers/net/netdevsim/bus.c:184
#4: ffff88805ef4f0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#4: ffff88805ef4f0d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#5: ffff88805ef4e300 (&devlink->lock_key#37){+.+.}-{4:4}, at: nsim_drv_probe+0xc2/0xba0 drivers/net/netdevsim/dev.c:1582
#6: ffffffff8ecd3178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#6: ffffffff8ecd3178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2142
4 locks held by syz-executor/13720:
#0: ffff88801111e488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3108 [inline]
#0: ffff88801111e488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff8880398a2878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325
#2: ffff888026b12968 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326
#3: ffffffff8e542998 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/13832:
1 lock held by syz-executor/13850:
#0: ffffffff8ecd3178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8ecd3178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8ecd3178 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056
1 lock held by cmp/13852:
3 locks held by syz-executor/13853:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1188 Comm: irq/33-virtio1- Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:current_gfp_context include/linux/sched/mm.h:252 [inline]
RIP: 0010:fs_reclaim_acquire+0x28/0x100 mm/page_alloc.c:4244
Code: 90 90 f3 0f 1e fa 55 53 65 48 8b 1c 25 08 10 f6 91 48 83 c3 2c 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 0f 85 ad 00 00 00 8b 03 a9 00 00 0c 10 75 7d a9 00 08 00 00
RSP: 0018:ffffc90004f1e798 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff888026943bac RCX: dffffc0000000000
RDX: 00000000ffffffff RSI: 0000000000082820 RDI: 0000000000082820
RBP: 0000000000082820 R08: 0000000000000000 R09: 0000000000000100
R10: ffff888032890c80 R11: ffffffff81aae2f0 R12: 0000000000000140
R13: 0000000000082820 R14: ffff888140eaab40 R15: ffffffff88d7db1d
FS: 0000000000000000(0000) GS:ffff8881269bf000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff6e4947ff8 CR3: 00000000279a6000 CR4: 00000000003526f0
Call Trace:
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4142 [inline]
slab_alloc_node mm/slub.c:4220 [inline]
kmem_cache_alloc_node_noprof+0x45/0x330 mm/slub.c:4292
kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:578
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:669
alloc_skb include/linux/skbuff.h:1336 [inline]
__tcp_send_ack+0xaf/0x620 net/ipv4/tcp_output.c:4259
tcp_rcv_established+0x1439/0x1eb0 net/ipv4/tcp_input.c:6179
tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1926
tcp_v4_rcv+0x26a6/0x2f40 net/ipv4/tcp_ipv4.c:2368
ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
dst_input include/net/dst.h:471 [inline]
ip_sublist_rcv_finish+0x221/0x2a0 net/ipv4/ip_input.c:585
ip_list_rcv_finish net/ipv4/ip_input.c:634 [inline]
ip_sublist_rcv+0x6e7/0x9b0 net/ipv4/ip_input.c:642
ip_list_rcv+0x3e2/0x430 net/ipv4/ip_input.c:676
__netif_receive_skb_list_ptype net/core/dev.c:6034 [inline]
__netif_receive_skb_list_core+0x7d2/0x800 net/core/dev.c:6081
__netif_receive_skb_list net/core/dev.c:6133 [inline]
netif_receive_skb_list_internal+0x975/0xcc0 net/core/dev.c:6224
gro_normal_list include/net/gro.h:532 [inline]
gro_flush_normal include/net/gro.h:540 [inline]
napi_complete_done+0x2f2/0x7c0 net/core/dev.c:6593
virtqueue_napi_complete drivers/net/virtio_net.c:766 [inline]
virtnet_poll+0x23b0/0x2d80 drivers/net/virtio_net.c:3118
__napi_poll+0xb3/0x540 net/core/dev.c:7506
napi_poll net/core/dev.c:7569 [inline]
net_rx_action+0x707/0xe00 net/core/dev.c:7696
handle_softirqs+0x22f/0x710 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
__local_bh_enable_ip+0x179/0x270 kernel/softirq.c:259
local_bh_enable include/linux/bottom_half.h:33 [inline]
irq_forced_thread_fn+0xe9/0x120 kernel/irq/manage.c:1156
irq_thread+0x427/0x690 kernel/irq/manage.c:1256
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245