Re: [syzbot] [wireguard?] BUG: workqueue lockup in wg_packet_decrypt_worker

[syzbot <syzbot+d0d2f1a65f45b319d25d@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    71c3e5409eef Merge remote-tracking branch 'will/for-next/p..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=13fb40a5580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=42bd821301b42742
dashboard link: https://syzkaller.appspot.com/bug?extid=d0d2f1a65f45b319d25d
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=171efa8e580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1030649c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7596ece97a32/disk-71c3e540.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4d2c36351098/vmlinux-71c3e540.xz
kernel image: https://storage.googleapis.com/syzbot-assets/396ce0b85b3c/Image-71c3e540.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d0d2f1a65f45b319d25d@syzkaller.appspotmail.com

bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x2 nice=0 stuck for 58s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x100
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=12 refcnt=13
    in-flight: 4802:switchdev_deferred_process_work for 64s ,9:request_firmware_work_func for 147s ,4923:drm_fb_helper_damage_work for 58s ,10:nsim_fib_event_work for 68s
    pending: 2*ovs_dp_masks_rebalance, 2*nsim_dev_hwstats_traffic_work, psi_avgs_work, drm_fb_helper_damage_work, vmstat_shepherd, free_obj_work
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    in-flight: 26:free_ipc for 13s
    pending: nsim_dev_hwstats_traffic_work, psi_avgs_work
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=4 refcnt=5
    in-flight: 4976:cfg80211_wiphy_work for 110s cfg80211_wiphy_work ,1204:cfg80211_wiphy_work for 114s cfg80211_wiphy_work
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=12 refcnt=13
    in-flight: 240:cfg80211_wiphy_work for 48s ,14:cfg80211_wiphy_work for 112s cfg80211_wiphy_work ,4979:nsim_dev_trap_report_work for 0s ,48:nsim_dev_trap_report_work for 0s ,1190:cfg80211_wiphy_work for 105s cfg80211_wiphy_work ,4980:nsim_dev_trap_report_work for 0s ,4978:macvlan_process_broadcast for 3s
    pending: flush_memcg_stats_dwork, nsim_dev_trap_report_work, toggle_allocation_gate
workqueue events_power_efficient: flags=0x82
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=5 refcnt=6
    in-flight: 3700:neigh_periodic_work for 36s
    pending: 2*neigh_managed_work, fb_flashcursor, gc_worker
workqueue rcu_gp: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=4 MAYDAY
    pending: srcu_invoke_callbacks
workqueue netns: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=4
    in-flight: 12:cleanup_net for 116s
workqueue mm_percpu_wq: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=4 MAYDAY
    pending: vmstat_update
workqueue writeback: flags=0x4a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    in-flight: 59:wb_workfn for 111s
workqueue mld: flags=0x40108
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=55 MAYDAY
    pending: mld_dad_work
    inactive: mld_dad_work, 3*mld_ifc_work, mld_dad_work, 5*mld_ifc_work, 2*mld_dad_work, mld_ifc_work, mld_dad_work, 3*mld_ifc_work, mld_dad_work, 9*mld_ifc_work, 25*mld_dad_work
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=79 MAYDAY
    in-flight: 1495:mld_ifc_work for 0s
    inactive: mld_ifc_work, mld_dad_work, mld_ifc_work, 3*mld_dad_work, 4*mld_ifc_work, 2*mld_dad_work, mld_ifc_work, 2*mld_dad_work, mld_ifc_work, mld_dad_work, mld_ifc_work, 2*mld_dad_work, 4*mld_ifc_work, mld_dad_work, 4*mld_ifc_work, 2*mld_dad_work, 4*mld_ifc_work, 3*mld_dad_work, 4*mld_ifc_work, 4*mld_dad_work, 4*mld_ifc_work, mld_dad_work, 4*mld_ifc_work, mld_dad_work, 3*mld_ifc_work, 2*mld_dad_work, 4*mld_ifc_work, 10*mld_dad_work
workqueue ipv6_addrconf: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=222 MAYDAY
    in-flight: 2825(RESCUER):addrconf_dad_work for 64s
    inactive: 215*addrconf_dad_work, addrconf_verify_work
workqueue bat_events: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=50 MAYDAY
    in-flight: 2857(RESCUER):batadv_tt_purge for 1s
    pending: mayday_cursor_func
    inactive: batadv_mcast_mla_update, 2*batadv_iv_send_outstanding_bat_ogm_packet, 4*batadv_mcast_mla_update, batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, 9*batadv_iv_send_outstanding_bat_ogm_packet, batadv_mcast_mla_update, 3*batadv_purge_orig, 4*batadv_iv_send_outstanding_bat_ogm_packet, 2*batadv_purge_orig, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, 4*batadv_tt_purge
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 24:wg_packet_handshake_receive_worker for 1s
workqueue wg-crypt-wg0: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker, wg_packet_decrypt_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_encrypt_worker, wg_packet_decrypt_worker, wg_packet_tx_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=3 MAYDAY
    pending: wg_packet_decrypt_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=4 refcnt=7 MAYDAY
    in-flight: 4811:wg_packet_decrypt_worker for 64s wg_packet_decrypt_worker
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=4 refcnt=7 MAYDAY
    in-flight: 4471:wg_packet_decrypt_worker for 63s
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_encrypt_worker, wg_packet_decrypt_worker, wg_packet_tx_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=3 MAYDAY
    pending: wg_packet_decrypt_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=4 MAYDAY
    pending: wg_packet_decrypt_worker, wg_packet_tx_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=2 refcnt=3
    in-flight: 4977:wg_packet_handshake_receive_worker for 107s wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    in-flight: 1496:wg_packet_handshake_receive_worker for 12s wg_packet_handshake_receive_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x2 nice=0 active=3 refcnt=6 MAYDAY
    pending: wg_packet_tx_worker, wg_packet_decrypt_worker, wg_packet_encrypt_worker
pool 2: cpus=0 node=0 flags=0x2 nice=0 hung=58s workers=8 manager: 1091
pool 6: cpus=1 node=0 flags=0x0 nice=0 hung=0s workers=7 idle: 4930 866 4981
pool 8: cpus=0-1 flags=0x6 nice=0 hung=0s workers=13 manager: 40
Showing backtraces of busy workers in stalled worker pools:
pool 2:
task:kworker/0:5     state:R  running task     stack:0     pid:4811  tgid:4811  ppid:2      task_flags:0x4208060 flags:0x20000010
Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 preempt_schedule_common+0xd4/0x190 kernel/sched/core.c:7463
 preempt_schedule+0x60/0x78 kernel/sched/core.c:7487
 __local_bh_enable_ip+0x16c/0x234 kernel/softirq.c:480
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
 kernel_neon_begin+0x29c/0x400 arch/arm64/kernel/fpsimd.c:1924
 class_ksimd_constructor arch/arm64/include/asm/simd.h:48 [inline]
 poly1305_blocks+0x110/0x204 lib/crypto/arm64/poly1305.h:30
 poly1305_update+0x168/0x39c lib/crypto/poly1305.c:59
 chacha20poly1305_crypt_sg_inplace+0x888/0xc30 lib/crypto/chacha20poly1305.c:304
 chacha20poly1305_decrypt_sg_inplace+0x6c/0x94 lib/crypto/chacha20poly1305.c:353
 decrypt_packet drivers/net/wireguard/receive.c:278 [inline]
 wg_packet_decrypt_worker+0x490/0xa00 drivers/net/wireguard/receive.c:501
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854
pool 2:
task:kworker/0:7     state:R  running task     stack:0     pid:4977  tgid:4977  ppid:2      task_flags:0x4208060 flags:0x20000010
Workqueue: wg-kex-wg2 wg_packet_handshake_receive_worker
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 preempt_schedule_common+0xd4/0x190 kernel/sched/core.c:7463
 preempt_schedule+0x60/0x78 kernel/sched/core.c:7487
 __local_bh_enable_ip+0x16c/0x234 kernel/softirq.c:480
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
 kernel_neon_begin+0x29c/0x400 arch/arm64/kernel/fpsimd.c:1924
 class_ksimd_constructor arch/arm64/include/asm/simd.h:48 [inline]
 poly1305_blocks+0x110/0x204 lib/crypto/arm64/poly1305.h:30
 poly1305_update+0x168/0x39c lib/crypto/poly1305.c:59
 __chacha20poly1305_decrypt+0x240/0x39c lib/crypto/chacha20poly1305.c:151
 chacha20poly1305_decrypt+0x238/0x5e4 lib/crypto/chacha20poly1305.c:186
 message_decrypt+0x50/0x90 drivers/net/wireguard/noise.c:477
 wg_noise_handshake_consume_initiation+0x1a0/0x53c drivers/net/wireguard/noise.c:612
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:144 [inline]
 wg_packet_handshake_receive_worker+0x54c/0xcf8 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854
pool 2:
task:kworker/0:6     state:R  running task     stack:0     pid:4923  tgid:4923  ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: events drm_fb_helper_damage_work
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7376
 schedule_timeout+0x13c/0x28c kernel/time/sleep_timeout.c:99
 drm_crtc_wait_one_vblank+0x19c/0x440 drivers/gpu/drm/drm_vblank.c:1325
 drm_client_modeset_wait_for_vblank+0xc4/0xec drivers/gpu/drm/drm_client_modeset.c:1331
 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:327 [inline]
 drm_fb_helper_damage_work+0x520/0xbc0 drivers/gpu/drm/drm_fb_helper.c:365
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854
pool 2:
task:kworker/0:1     state:R  running task     stack:0     pid:10    tgid:10    ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: events nsim_fib_event_work
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7376
 schedule_timeout+0x13c/0x28c kernel/time/sleep_timeout.c:99
 schedule_timeout_uninterruptible+0x78/0xbc kernel/time/sleep_timeout.c:158
 msleep+0x3c/0x68 kernel/time/sleep_timeout.c:318
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event+0x57a0/0x60c4 drivers/net/netdevsim/fib.c:889
 nsim_fib_event_work+0x1d8/0x320 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854
pool 2:
task:kworker/0:3     state:R  running task     stack:0     pid:4471  tgid:4471  ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: wg-crypt-wg0 wg_packet_decrypt_worker
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x135c/0x2b00 kernel/sched/core.c:7284
 preempt_schedule_common+0xd4/0x190 kernel/sched/core.c:7463
 preempt_schedule+0x60/0x78 kernel/sched/core.c:7487
 __local_bh_enable_ip+0x16c/0x234 kernel/softirq.c:480
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:237 [inline]
 _raw_spin_unlock_bh+0x3c/0x4c kernel/locking/spinlock.c:245
 spin_unlock_bh include/linux/spinlock.h:407 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:399 [inline]
 wg_packet_decrypt_worker+0x254/0xa00 drivers/net/wireguard/receive.c:499
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854
net_ratelimit: 70318 callbacks suppressed
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)


---
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