============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
udevd/4177 is trying to acquire lock:
ffff8880211a3218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
ffff8880211a3218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3922 [inline]
ffff8880211a3218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1e69/0x2e50 net/core/dev.c:4266
but task is already holding lock:
ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:174 [inline]
ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3884 [inline]
ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x108d/0x2e50 net/core/dev.c:4266
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
*** DEADLOCK ***
May be due to missing lock nesting notation
11 locks held by udevd/4177:
#0: ffffffff8d6c12b8 (tomoyo_ss){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#1: ffffc90000dd0bc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#1: ffffc90000dd0bc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xca/0x540 kernel/time/timer.c:1638
#2: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#3: ffffffff8d11f000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#4: ffffffff8d11f000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#5: ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
#5: ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:174 [inline]
#5: ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3884 [inline]
#5: ffff8880221fd258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x108d/0x2e50 net/core/dev.c:4266
#6: ffff88802c85b360 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
#6: ffff88802c85b360 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:118 [inline]
#6: ffff88802c85b360 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xbe5/0x19a0 net/ipv6/icmp.c:551
#7: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#8: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#9: ffffffff8d11f000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#10: ffffffff8d11f000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
stack backtrace:
CPU: 1 PID: 4177 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_deadlock kernel/locking/lockdep.c:3048 [inline]
validate_chain kernel/locking/lockdep.c:3842 [inline]
__lock_acquire+0x67eb/0x7d40 kernel/locking/lockdep.c:5120
lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:364 [inline]
__dev_xmit_skb net/core/dev.c:3922 [inline]
__dev_queue_xmit+0x1e69/0x2e50 net/core/dev.c:4266
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0x1134/0x1640 net/ipv6/ip6_output.c:132
ip6_send_skb+0x1af/0x350 net/ipv6/ip6_output.c:1886
icmp6_send+0x134a/0x19a0 net/ipv6/icmp.c:630
__icmpv6_send include/linux/icmpv6.h:28 [inline]
icmpv6_send include/linux/icmpv6.h:49 [inline]
ip6_pkt_drop+0x55a/0x690 net/ipv6/route.c:4539
ip6_pkt_discard_out+0xee/0x110 net/ipv6/route.c:4552
ip6tunnel_xmit+0x1ac/0x3d0 include/net/ip6_tunnel.h:160
ip6_tnl_xmit+0x1b65/0x2260 net/ipv6/ip6_tunnel.c:1267
__gre6_xmit+0x960/0xc70 net/ipv6/ip6_gre.c:787
ip6gre_xmit_ipv6 net/ipv6/ip6_gre.c:843 [inline]
ip6gre_tunnel_xmit+0xcad/0x1080 net/ipv6/ip6_gre.c:895
__netdev_start_xmit include/linux/netdevice.h:5049 [inline]
netdev_start_xmit include/linux/netdevice.h:5063 [inline]
xmit_one net/core/dev.c:3662 [inline]
dev_hard_start_xmit+0x297/0x7d0 net/core/dev.c:3678
sch_direct_xmit+0x24d/0x4a0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3897 [inline]
__dev_queue_xmit+0x1694/0x2e50 net/core/dev.c:4266
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0x1134/0x1640 net/ipv6/ip6_output.c:132
dst_output include/net/dst.h:452 [inline]
NF_HOOK include/linux/netfilter.h:302 [inline]
ndisc_send_skb+0xb7c/0x1410 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3974
call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
expire_timers kernel/time/timer.c:1699 [inline]
__run_timers+0x56c/0x810 kernel/time/timer.c:1970
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
handle_softirqs+0x336/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
RIP: 0010:tomoyo_check_acl+0x30e/0x420 security/tomoyo/domain.c:184
Code: 49 81 c5 e0 08 00 00 4c 8d 73 ff 44 89 f7 c1 ef 03 81 e7 f8 1f 00 00 4c 01 ff be 08 00 00 00 e8 98 0d 15 fe 31 f6 4d 0f a3 37 <40> 0f 93 c5 40 0f 92 c6 bf 02 00 00 00 e8 50 c9 cf fd 40 84 ed 74
RSP: 0018:ffffc90002e1f930 EFLAGS: 00000246
RAX: ffffffff83a95c01 RBX: 00000000000000fe RCX: ffffffff83a95c58
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88807d01f448
RBP: ffff88807d01f401 R08: ffff88807d01f44f R09: 1ffff1100fa03e89
R10: dffffc0000000000 R11: ffffed100fa03e8a R12: dffffc0000000000
R13: 00000000000018b0 R14: 00000000000000fd R15: ffff88807d01f430
tomoyo_path_permission+0x1a6/0x3a0 security/tomoyo/file.c:586
tomoyo_path_perm+0x423/0x5d0 security/tomoyo/file.c:838
security_inode_getattr+0xcf/0x120 security/security.c:1398
vfs_getattr+0x26/0x3a0 fs/stat.c:157
vfs_statx+0x146/0x4c0 fs/stat.c:225
vfs_fstatat fs/stat.c:243 [inline]
__do_sys_newfstatat fs/stat.c:411 [inline]
__se_sys_newfstatat fs/stat.c:405 [inline]
__x64_sys_newfstatat+0x15f/0x200 fs/stat.c:405
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9501925b0a
Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
RSP: 002b:00007fffc0a499d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 00007f9501925b0a
RDX: 00007fffc0a499e0 RSI: 00007fffc0a49ab0 RDI: 00000000ffffff9c
RBP: 00007fffc0a4aaf0 R08: 000055a95f058010 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000055a95f058010
R13: 0000000000000000 R14: 000055a94ed1f6d7 R15: 00007fffc0a4bc40
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
----------------
Code disassembly (best guess):
0: 49 81 c5 e0 08 00 00 add $0x8e0,%r13
7: 4c 8d 73 ff lea -0x1(%rbx),%r14
b: 44 89 f7 mov %r14d,%edi
e: c1 ef 03 shr $0x3,%edi
11: 81 e7 f8 1f 00 00 and $0x1ff8,%edi
17: 4c 01 ff add %r15,%rdi
1a: be 08 00 00 00 mov $0x8,%esi
1f: e8 98 0d 15 fe call 0xfe150dbc
24: 31 f6 xor %esi,%esi
26: 4d 0f a3 37 bt %r14,(%r15)
* 2a: 40 0f 93 c5 setae %bpl <-- trapping instruction
2e: 40 0f 92 c6 setb %sil
32: bf 02 00 00 00 mov $0x2,%edi
37: e8 50 c9 cf fd call 0xfdcfc98c
3c: 40 84 ed test %bpl,%bpl
3f: 74 .byte 0x74