============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
modprobe/10999 is trying to acquire lock:
ffff88807bb12158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff88807bb12158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4791 [inline]
ffff88807bb12158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
but task is already holding lock:
ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4791 [inline]
ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&qdisc_xmit_lock_key#4);
lock(&qdisc_xmit_lock_key#4);
*** DEADLOCK ***
May be due to missing lock nesting notation
12 locks held by modprobe/10999:
#0: ffff888087b527f8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
#0: ffff888087b527f8 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x234/0x4f0 mm/util.c:579
#1: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
#1: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa6/0x2550 arch/x86/kernel/unwind_orc.c:495
#2: ffffc90000a08cc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
#3: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x215/0x1670 net/ipv6/ndisc.c:482
#4: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550 net/ipv6/ip6_output.c:234
#5: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#5: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#5: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4792
#6: ffff888056544228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
#6: ffff888056544228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#6: ffff888056544228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4197 [inline]
#6: ffff888056544228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4832
#7: ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
#7: ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4791 [inline]
#7: ffff888031fee958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
#8: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#8: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#8: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450 net/ipv4/ip_output.c:433
#9: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#9: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#9: ffffffff8e95cca0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3c2/0x1070 net/ipv4/ip_output.c:230
#10: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#10: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#10: ffffffff8e95cd00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4792
#11: ffff88807baa7228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
#11: ffff88807baa7228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#11: ffff88807baa7228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4197 [inline]
#11: ffff88807baa7228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4832
stack backtrace:
CPU: 1 UID: 0 PID: 10999 Comm: modprobe Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain kernel/locking/lockdep.c:3895 [inline]
__lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
spin_lock include/linux/spinlock.h:342 [inline]
__netif_tx_lock include/linux/netdevice.h:4791 [inline]
sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
__dev_xmit_skb net/core/dev.c:4210 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4832
neigh_output include/net/neighbour.h:560 [inline]
ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
iptunnel_xmit+0x621/0xd10 net/ipv4/ip_tunnel_core.c:97
ip_tunnel_xmit+0x193a/0x1f20 net/ipv4/ip_tunnel.c:845
__gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491
erspan_xmit+0xa41/0x14d0 net/ipv4/ip_gre.c:750
__netdev_start_xmit include/linux/netdevice.h:5378 [inline]
netdev_start_xmit include/linux/netdevice.h:5387 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904
sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372
__dev_xmit_skb net/core/dev.c:4210 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4832
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
dst_output include/net/dst.h:470 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
ndisc_send_skb+0xd0b/0x1670 net/ipv6/ndisc.c:512
addrconf_rs_timer+0x395/0x6d0 net/ipv6/addrconf.c:4064
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x843/0x2550 arch/x86/kernel/unwind_orc.c:530
Code: 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 02 23 ba 00 48 8b 3b 48 85 ff 0f 84 4e 0e 00 00 48 83 c7 60 e9 aa 02 00 00 <83> fb 03 0f 84 65 01 00 00 83 fb 04 0f 85 d7 0c 00 00 49 8d 5e 40
RSP: 0018:ffffc9000321ed58 EFLAGS: 00000202
RAX: ffffc9000321ee5d RBX: 0000000000000004 RCX: ffffffff9051b884
RDX: ffffffff90d1c1e6 RSI: ffffffff90d1c1ea RDI: ffffffff8c28b780
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8e95cca0
R10: ffffc9000321ee78 R11: ffffffff81b0e0e0 R12: ffffffff90d1c1eb
R13: 1ffff92000643dc5 R14: ffffc9000321ee28 R15: ffffc9000321ee60
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4570 [inline]
slab_alloc_node mm/slub.c:4899 [inline]
kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906
vm_area_dup+0x2b/0x680 mm/vma_init.c:123
__split_vma+0x1dc/0xa50 mm/vma.c:516
vms_gather_munmap_vmas+0x32d/0x1380 mm/vma.c:1427
__mmap_setup mm/vma.c:2439 [inline]
__mmap_region mm/vma.c:2753 [inline]
mmap_region+0x921/0x22a0 mm/vma.c:2857
do_mmap+0xc39/0x10c0 mm/mmap.c:560
vm_mmap_pgoff+0x2c9/0x4f0 mm/util.c:581
ksys_mmap_pgoff+0x51e/0x760 mm/mmap.c:606
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0592c3f242
Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00
RSP: 002b:00007ffdc3aceb38 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f0592920000 RCX: 00007f0592c3f242
RDX: 0000000000000005 RSI: 000000000001c000 RDI: 00007f0592920000
RBP: 0000000000000812 R08: 0000000000000000 R09: 0000000000008000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffdc3aceb88
R13: 00007f0592c14ab0 R14: 00007ffdc3acefb0 R15: 00000fffb8759d6a
----------------
Code disassembly (best guess):
0: 48 89 d8 mov %rbx,%rax
3: 48 c1 e8 03 shr $0x3,%rax
7: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
b: 74 08 je 0x15
d: 48 89 df mov %rbx,%rdi
10: e8 02 23 ba 00 call 0xba2317
15: 48 8b 3b mov (%rbx),%rdi
18: 48 85 ff test %rdi,%rdi
1b: 0f 84 4e 0e 00 00 je 0xe6f
21: 48 83 c7 60 add $0x60,%rdi
25: e9 aa 02 00 00 jmp 0x2d4
* 2a: 83 fb 03 cmp $0x3,%ebx <-- trapping instruction
2d: 0f 84 65 01 00 00 je 0x198
33: 83 fb 04 cmp $0x4,%ebx
36: 0f 85 d7 0c 00 00 jne 0xd13
3c: 49 8d 5e 40 lea 0x40(%r14),%rbx