syzbot


BUG: soft lockup in dev_ioctl

Status: upstream: reported on 2025/07/20 19:44
Reported-by: syzbot+179f590de579b45703fe@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-15 BUG: soft lockup in dev_ioctl 1 7 370d 459d 0/2 auto-obsoleted due to no activity on 2024/10/24 08:58
upstream BUG: soft lockup in dev_ioctl (2) mm 1 4 29d 89d 0/29 moderation: reported on 2025/05/02 14:45
upstream BUG: soft lockup in dev_ioctl batman 1 2 442d 507d 0/29 auto-obsoleted due to no activity on 2024/08/13 06:45
linux-4.19 INFO: rcu detected stall in dev_ioctl (2) 1 1 1432d 1432d 0/1 auto-closed as invalid on 2021/12/27 14:21
upstream INFO: rcu detected stall in dev_ioctl batman 1 18 1207d 2074d 0/29 auto-closed as invalid on 2022/08/09 13:29
linux-4.19 INFO: rcu detected stall in dev_ioctl (3) 1 1 1308d 1308d 0/1 auto-closed as invalid on 2022/04/29 15:27
linux-5.15 INFO: rcu detected stall in dev_ioctl 1 1 241d 241d 0/3 auto-obsoleted due to no activity on 2025/03/11 17:46
upstream INFO: rcu detected stall in dev_ioctl (2) mm 1 3 206d 290d 0/29 auto-obsoleted due to no activity on 2025/04/05 21:09

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz.4.470:6457]
Modules linked in:
irq event stamp: 375199
hardirqs last  enabled at (375198): [<ffff8000083b94f4>] seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline]
hardirqs last  enabled at (375198): [<ffff8000083b94f4>] timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
hardirqs last  enabled at (375198): [<ffff8000083b94f4>] timekeeping_get_ns+0x124/0x3b8 kernel/time/timekeeping.c:388
hardirqs last disabled at (375199): [<ffff800011944e78>] __el1_irq arch/arm64/kernel/entry-common.c:468 [inline]
hardirqs last disabled at (375199): [<ffff800011944e78>] el1_interrupt+0x24/0x54 arch/arm64/kernel/entry-common.c:486
softirqs last  enabled at (170): [<ffff80001137d6d0>] spin_unlock_bh include/linux/spinlock.h:396 [inline]
softirqs last  enabled at (170): [<ffff80001137d6d0>] tipc_disc_reset+0x1dc/0x2f8 net/tipc/discover.c:417
softirqs last disabled at (172): [<ffff80000fd2eeb8>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
CPU: 0 PID: 6457 Comm: syz.4.470 Not tainted 6.1.146-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : cake_heap_get_backlog net/sched/sch_cake.c:1472 [inline]
pc : cake_heapify+0xe4/0x530 net/sched/sch_cake.c:1478
lr : cake_heapify+0x5c/0x530 net/sched/sch_cake.c:1481
sp : ffff800020966c10
x29: ffff800020966c20 x28: 1fffe0001b16485b x27: ffff0000ee200000
x26: 0000000000016a13 x25: ffff0000d8b242d8 x24: 00000000000002d8
x23: dfff800000000000 x22: ffff0000ee200000 x21: ffff0000ee21416c
x20: ffff0000d8b202d0 x19: 00000000000002d8 x18: ffff800011aabce0
x17: ffff8000181e7000 x16: ffff8000082d2400 x15: ffff800017cc7fc0
x14: ffff0000d672a658 x13: 1ffff00002a160b1 x12: 0000000000ff0100
x11: ff0080000ffb914c x10: 00000000000198d0 x9 : 0000000000000007
x8 : 0000000000000000 x7 : ffff8000083b9900 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000002 x1 : 00000000000002d8 x0 : 0000000000002000
Call trace:
 cake_heap_get_backlog net/sched/sch_cake.c:1472 [inline]
 cake_heapify+0xe4/0x530 net/sched/sch_cake.c:1478
 cake_drop net/sched/sch_cake.c:1575 [inline]
 cake_enqueue+0x333c/0x6880 net/sched/sch_cake.c:1945
 cbs_child_enqueue net/sched/sch_cbs.c:95 [inline]
 cbs_enqueue_soft+0x14c/0x230 net/sched/sch_cbs.c:128
 cbs_enqueue+0x54/0x68 net/sched/sch_cbs.c:136
 dev_qdisc_enqueue+0x5c/0x38c net/core/dev.c:3863
 __dev_xmit_skb net/core/dev.c:3952 [inline]
 __dev_queue_xmit+0xad0/0x309c net/core/dev.c:4300
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 tipc_l2_send_msg+0x29c/0x35c net/tipc/bearer.c:518
 tipc_bearer_xmit_skb+0x244/0x384 net/tipc/bearer.c:577
 tipc_disc_reset+0x200/0x2f8 net/tipc/discover.c:419
 tipc_reset_bearer+0x5c/0x84 net/tipc/bearer.c:387
 tipc_l2_device_event+0x498/0x778 net/tipc/bearer.c:-1
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
 call_netdevice_notifiers_info net/core/dev.c:2001 [inline]
 call_netdevice_notifiers_mtu+0x118/0x19c net/core/dev.c:2076
 dev_set_mtu_ext+0x350/0x514 net/core/dev.c:8768
 dev_set_mtu+0x50/0xe8 net/core/dev.c:8789
 dev_ifsioc+0x250/0xed0 net/core/dev_ioctl.c:334
 dev_ioctl+0x4c8/0xc8c net/core/dev_ioctl.c:588
 sock_do_ioctl+0x18c/0x240 net/socket.c:1218
 sock_ioctl+0x5c4/0x840 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/20 19:43 linux-6.1.y 3369c6df2fae 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: soft lockup in dev_ioctl
* Struck through repros no longer work on HEAD.