[v6.1] BUG: soft lockup in dev_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3369c6df2fae Linux 6.1.146
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15e4cb82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=aafe227a6f76c0c3
dashboard link: https://syzkaller.appspot.com/bug?extid=179f590de579b45703fe
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c6c6f55858e8/disk-3369c6df.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a99117bdae3d/vmlinux-3369c6df.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9ca71d7a5035/Image-3369c6df.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+179f59...@syzkaller.appspotmail.com

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


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