BUG: soft lockup in br_ip4_multicast_query_expired

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b86ee2b7ae42 Linux 4.14.264
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12fb0fcc700000
kernel config: https://syzkaller.appspot.com/x/.config?x=3fffc4e0823c0d50
dashboard link: https://syzkaller.appspot.com/bug?extid=21390f781dffc7626887
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1563f480700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=121fd052700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+21390f...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [ksoftirqd/0:7]
Modules linked in:
irq event stamp: 11566697
hardirqs last enabled at (11566696): [<ffffffff817eafd0>] slab_alloc_node mm/slab.c:3327 [inline]
hardirqs last enabled at (11566696): [<ffffffff817eafd0>] kmem_cache_alloc_node_trace+0x2f0/0x400 mm/slab.c:3659
hardirqs last disabled at (11566697): [<ffffffff874018ae>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:793
softirqs last enabled at (4038750): [<ffffffff8760068b>] __do_softirq+0x68b/0x9ff kernel/softirq.c:314
softirqs last disabled at (4038755): [<ffffffff81321940>] run_ksoftirqd+0x50/0x1a0 kernel/softirq.c:670
CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted 4.14.264-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880b540a1c0 task.stack: ffff8880b5418000
RIP: 0010:unwind_get_return_address arch/x86/kernel/unwind_orc.c:252 [inline]
RIP: 0010:unwind_get_return_address+0x42/0x90 arch/x86/kernel/unwind_orc.c:247
RSP: 0018:ffff8880b541f688 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff10
RAX: dffffc0000000000 RBX: ffff8880b541f6b0 RCX: 0000000000000000
RDX: 1ffff11016a83edf RSI: ffff8880b541f5a0 RDI: ffff8880b541f6b0
RBP: ffff8880b541f6f8 R08: 0000000000000001 R09: 0000000000000001
R10: ffff8880b541fc18 R11: 0000000000000001 R12: ffff8880b541f738
R13: 0000000000000000 R14: ffff88813fe74940 R15: 00000000000001c0
FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c63de69d60 CR3: 0000000008e6a000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__save_stack_trace+0xa0/0x160 arch/x86/kernel/stacktrace.c:45
save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0x96/0x510 net/core/skbuff.c:205
__netdev_alloc_skb+0x54/0x430 net/core/skbuff.c:407
__netdev_alloc_skb_ip_align include/linux/skbuff.h:2696 [inline]
netdev_alloc_skb_ip_align include/linux/skbuff.h:2706 [inline]
br_ip4_multicast_alloc_query net/bridge/br_multicast.c:382 [inline]
br_multicast_alloc_query net/bridge/br_multicast.c:581 [inline]
__br_multicast_send_query+0x109f/0x2db0 net/bridge/br_multicast.c:914
br_multicast_send_query+0x1c6/0x340 net/bridge/br_multicast.c:961
br_multicast_query_expired net/bridge/br_multicast.c:1914 [inline]
br_ip4_multicast_query_expired+0xd0/0x100 net/bridge/br_multicast.c:1922
call_timer_fn+0x14a/0x650 kernel/time/timer.c:1280
expire_timers+0x232/0x4d0 kernel/time/timer.c:1319
__run_timers kernel/time/timer.c:1637 [inline]
run_timer_softirq+0x1d5/0x5a0 kernel/time/timer.c:1650
__do_softirq+0x24d/0x9ff kernel/softirq.c:288
run_ksoftirqd+0x50/0x1a0 kernel/softirq.c:670
smpboot_thread_fn+0x5c1/0x920 kernel/smpboot.c:164
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: b6 04 02 84 c0 74 04 3c 03 7e 51 8b 03 85 c0 75 05 5b 31 c0 5d c3 48 8d 6b 48 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 32 48 8b 7b 48 e8 6f a4 13 00 85 c0 74 d3 48 b8
----------------
Code disassembly (best guess):
0: b6 04 mov $0x4,%dh
2: 02 84 c0 74 04 3c 03 add 0x33c0474(%rax,%rax,8),%al
9: 7e 51 jle 0x5c
b: 8b 03 mov (%rbx),%eax
d: 85 c0 test %eax,%eax
f: 75 05 jne 0x16
11: 5b pop %rbx
12: 31 c0 xor %eax,%eax
14: 5d pop %rbp
15: c3 retq
16: 48 8d 6b 48 lea 0x48(%rbx),%rbp
1a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
21: fc ff df
24: 48 89 ea mov %rbp,%rdx
27: 48 c1 ea 03 shr $0x3,%rdx
* 2b: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2f: 75 32 jne 0x63
31: 48 8b 7b 48 mov 0x48(%rbx),%rdi
35: e8 6f a4 13 00 callq 0x13a4a9
3a: 85 c0 test %eax,%eax
3c: 74 d3 je 0x11
3e: 48 rex.W
3f: b8 .byte 0xb8


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