============================================ WARNING: possible recursive locking detected 6.8.0-syzkaller-05204-g237bb5f7f7f5 #0 Not tainted -------------------------------------------- syz-executor.1/5083 is trying to acquire lock: ffff88805fef93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88805fef93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline] ffff88805fef93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline] ffff88805fef93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974 but task is already holding lock: ffff8880234c53e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880234c53e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&br->multicast_lock); lock(&br->multicast_lock); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz-executor.1/5083: #0: ffffffff8e1dadf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:637 [inline] #0: ffffffff8e1dadf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1687 [inline] #0: ffffffff8e1dadf0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x272/0x21b0 kernel/fork.c:1736 #1: ffff88807c45a7a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:124 [inline] #1: ffff88807c45a7a0 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:638 [inline] #1: ffff88807c45a7a0 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1687 [inline] #1: ffff88807c45a7a0 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x292/0x21b0 kernel/fork.c:1736 #2: ffff88807b89b120 (&mm->mmap_lock/1){+.+.}-{3:3}, at: mmap_write_lock_nested include/linux/mmap_lock.h:115 [inline] #2: ffff88807b89b120 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mmap kernel/fork.c:647 [inline] #2: ffff88807b89b120 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mm kernel/fork.c:1687 [inline] #2: ffff88807b89b120 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_mm+0x3cc/0x21b0 kernel/fork.c:1736 #3: ffffc90000007c00 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x600 kernel/time/timer.c:1789 #4: ffff8880234c53e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff8880234c53e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905 #5: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #5: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4260 #6: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #6: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #6: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4260 #7: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #7: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #7: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x1b9/0x1a10 net/bridge/br_device.c:44 stack backtrace: CPU: 0 PID: 5083 Comm: syz-executor.1 Not tainted 6.8.0-syzkaller-05204-g237bb5f7f7f5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline] br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974 br_dev_xmit+0xb17/0x1a10 net/bridge/br_device.c:90 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547 __dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335 dev_queue_xmit include/linux/netdevice.h:3091 [inline] vlan_dev_hard_start_xmit+0x36c/0x5f0 net/8021q/vlan_dev.c:125 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547 __dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335 dev_queue_xmit include/linux/netdevice.h:3091 [inline] br_dev_queue_push_xmit+0x701/0x8d0 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:314 [inline] __br_multicast_send_query+0x2ecb/0x4750 net/bridge/br_multicast.c:1809 br_multicast_send_query+0x4ee/0x6b0 net/bridge/br_multicast.c:1888 br_multicast_port_query_expired+0x2d4/0x3b0 net/bridge/br_multicast.c:1913 call_timer_fn+0x17e/0x600 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers kernel/time/timer.c:2408 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2419 run_timer_base kernel/time/timer.c:2428 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2438 __do_softirq+0x2bc/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:225 Code: f0 15 00 00 83 fa 02 75 21 48 8b 91 f8 15 00 00 48 8b 32 48 8d 7e 01 8b 89 f4 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 RSP: 0018:ffffc90003c8ee20 EFLAGS: 00000293 RAX: ffffffff814090bb RBX: 0000000000000000 RCX: ffff888027851e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff81409031 RBP: ffffc90003c8ef00 R08: ffffffff81409011 R09: ffffc90003c8eff0 R10: 0000000000000003 R11: ffffffff8180dbc0 R12: ffff888027851e00 R13: ffffc90003c8ef50 R14: 0000000000000001 R15: ffffffff81dfca2e unwind_next_frame+0x14b/0x2a00 arch/x86/kernel/unwind_orc.c:482 arch_stack_walk+0x151/0x1b0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc+0x172/0x350 mm/slub.c:3867 ptlock_alloc mm/memory.c:6290 [inline] ptlock_init include/linux/mm.h:2906 [inline] pmd_ptlock_init include/linux/mm.h:3006 [inline] pagetable_pmd_ctor include/linux/mm.h:3044 [inline] pmd_alloc_one include/asm-generic/pgalloc.h:137 [inline] __pmd_alloc+0x110/0x630 mm/memory.c:5716 pmd_alloc include/linux/mm.h:2805 [inline] copy_pmd_range mm/memory.c:1167 [inline] copy_pud_range mm/memory.c:1224 [inline] copy_p4d_range mm/memory.c:1248 [inline] copy_page_range+0x3c8e/0x4240 mm/memory.c:1346 dup_mmap kernel/fork.c:747 [inline] dup_mm kernel/fork.c:1687 [inline] copy_mm+0x12f5/0x21b0 kernel/fork.c:1736 copy_process+0x187a/0x3df0 kernel/fork.c:2389 kernel_clone+0x21e/0x8d0 kernel/fork.c:2796 __do_sys_clone kernel/fork.c:2939 [inline] __se_sys_clone kernel/fork.c:2923 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2923 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fbb51a7add3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe51549728 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbb51a7add3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 000055555a0ea750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog ---------------- Code disassembly (best guess): 0: f0 15 00 00 83 fa lock adc $0xfa830000,%eax 6: 02 75 21 add 0x21(%rbp),%dh 9: 48 8b 91 f8 15 00 00 mov 0x15f8(%rcx),%rdx 10: 48 8b 32 mov (%rdx),%rsi 13: 48 8d 7e 01 lea 0x1(%rsi),%rdi 17: 8b 89 f4 15 00 00 mov 0x15f4(%rcx),%ecx 1d: 48 39 cf cmp %rcx,%rdi 20: 73 08 jae 0x2a 22: 48 89 3a mov %rdi,(%rdx) 25: 48 89 44 f2 08 mov %rax,0x8(%rdx,%rsi,8) * 2a: c3 ret <-- trapping instruction 2b: cc int3 2c: cc int3 2d: cc int3 2e: cc int3 2f: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 36: 00 00 00 39: 0f 1f 40 00 nopl 0x0(%rax) 3d: 90 nop 3e: 90 nop 3f: 90 nop