============================================ WARNING: possible recursive locking detected 6.8.0-syzkaller-05204-g237bb5f7f7f5 #0 Not tainted -------------------------------------------- syz-executor.1/26061 is trying to acquire lock: ffff8880291d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880291d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline] ffff8880291d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline] ffff8880291d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974 but task is already holding lock: ffff88802a5b93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88802a5b93e0 (&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 9 locks held by syz-executor.1/26061: #0: ffff888029c4a420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409 #1: ffff88807eb56800 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:828 [inline] #1: ffff88807eb56800 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4387 #2: ffff8880588ec000 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline] #2: ffff8880588ec000 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: vfs_unlink+0xe4/0x600 fs/namei.c:4325 #3: ffff88802f5fa950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1faa/0x2200 fs/jbd2/transaction.c:463 #4: ffffc90000a08c00 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x600 kernel/time/timer.c:1789 #5: ffff88802a5b93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #5: ffff88802a5b93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905 #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: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #7: ffffffff8e131980 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4260 #8: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #8: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #8: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x1b9/0x1a10 net/bridge/br_device.c:44 stack backtrace: CPU: 1 PID: 26061 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:__ext4_journal_stop+0xa2/0x1a0 fs/ext4/ext4_jbd2.c:128 Code: ff df 48 8d 7b 20 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 e3 00 00 00 44 8b 63 20 48 89 d8 48 c1 e8 03 42 80 3c 30 00 <74> 08 48 89 df e8 64 ff a8 ff 4c 8b 2b 4d 85 ed 0f 84 81 00 00 00 RSP: 0018:ffffc90004bc7b20 EFLAGS: 00000246 RAX: 1ffff1100aa3d4dc RBX: ffff8880551ea6e0 RCX: ffff88806f7e8000 RDX: 0000000000000000 RSI: 0000000000000ce0 RDI: ffff8880551ea700 RBP: 0000000000000ce0 R08: ffffffff826a1c3f R09: 1ffff1100fd10385 R10: dffffc0000000000 R11: ffffed100fd10386 R12: 0000000000000000 R13: 1ffff92000978f78 R14: dffffc0000000000 R15: ffffffff8d8e95d4 __ext4_unlink+0x931/0xb30 fs/ext4/namei.c:3296 ext4_unlink+0x1af/0x560 fs/ext4/namei.c:3321 vfs_unlink+0x365/0x600 fs/namei.c:4336 do_unlinkat+0x4ae/0x830 fs/namei.c:4400 __do_sys_unlink fs/namei.c:4448 [inline] __se_sys_unlink fs/namei.c:4446 [inline] __x64_sys_unlink+0x49/0x60 fs/namei.c:4446 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f586727d557 Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe49e9a588 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f586727d557 RDX: 00007ffe49e9a5b0 RSI: 00007ffe49e9a640 RDI: 00007ffe49e9a640 RBP: 00007ffe49e9a640 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe49e9b700 R13: 00007f58672c93b9 R14: 000000000008e950 R15: 0000000000000006 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: df 48 8d fisttps -0x73(%rax) 3: 7b 20 jnp 0x25 5: 48 89 f8 mov %rdi,%rax 8: 48 c1 e8 03 shr $0x3,%rax c: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax 11: 84 c0 test %al,%al 13: 0f 85 e3 00 00 00 jne 0xfc 19: 44 8b 63 20 mov 0x20(%rbx),%r12d 1d: 48 89 d8 mov %rbx,%rax 20: 48 c1 e8 03 shr $0x3,%rax 24: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) * 29: 74 08 je 0x33 <-- trapping instruction 2b: 48 89 df mov %rbx,%rdi 2e: e8 64 ff a8 ff call 0xffa8ff97 33: 4c 8b 2b mov (%rbx),%r13 36: 4d 85 ed test %r13,%r13 39: 0f 84 81 00 00 00 je 0xc0