============================================ WARNING: possible recursive locking detected 5.15.0-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:1/10 is trying to acquire lock: ffffffff90560610 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577 but task is already holding lock: ffffffff90560610 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by kworker/u4:1/10: #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline] #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline] #0: ffff88814b141938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269 #1: ffffc90000cf7db0 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273 #2: ffffffff8b983a20 (rcu_read_lock){....}-{1:2}, at: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline] #2: ffffffff8b983a20 (rcu_read_lock){....}-{1:2}, at: batadv_nc_worker+0xf3/0xfa0 net/batman-adv/network-coding.c:723 #3: ffffffff8b983a20 (rcu_read_lock){....}-{1:2}, at: ieee80211_iterate_active_interfaces_atomic+0x0/0x180 net/mac80211/util.c:1233 #4: ffffffff8b983a20 (rcu_read_lock){....}-{1:2}, at: __ieee80211_beacon_get+0x0/0x15e0 net/mac80211/tx.c:5449 #5: ffff88807eaed4b0 (&i->lock){-.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #5: ffff88807eaed4b0 (&i->lock){-.-.}-{2:2}, at: serial8250_interrupt+0x3a/0x200 drivers/tty/serial/8250/8250_core.c:116 #6: ffffffff90560610 (&port_lock_key){-.-.}-{2:2}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1908 #7: ffff888035231098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:273 stack backtrace: CPU: 0 PID: 10 Comm: kworker/u4:1 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 uart_write+0x12c/0x570 drivers/tty/serial/serial_core.c:577 n_hdlc_send_frames+0x24b/0x490 drivers/tty/n_hdlc.c:290 tty_wakeup+0xe1/0x120 drivers/tty/tty_io.c:534 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:51 serial8250_tx_chars+0x4f3/0xad0 drivers/tty/serial/8250/8250_port.c:1845 serial8250_handle_irq.part.0+0x328/0x3d0 drivers/tty/serial/8250/8250_port.c:1932 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1905 [inline] serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x303/0x8f0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:198 [inline] handle_irq_event+0x102/0x280 kernel/irq/handle.c:215 handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:822 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250 common_interrupt+0x4d/0xc0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:30 [inline] RIP: 0010:__orc_find+0x6f/0xf0 arch/x86/kernel/unwind_orc.c:52 Code: 72 4d 4c 89 e0 48 29 e8 48 89 c2 48 c1 e8 3f 48 c1 fa 02 48 01 d0 48 d1 f8 48 8d 5c 85 00 48 89 d8 48 c1 e8 03 42 0f b6 14 38 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 48 48 63 03 48 01 RSP: 0018:ffffc900000076d8 EFLAGS: 00000212 RAX: 1ffffffff1afe370 RBX: ffffffff8d7f1b80 RCX: ffffffff8162ac49 RDX: 0000000000000000 RSI: ffffffff8dee4b02 RDI: ffffffff8d7f1b60 RBP: ffffffff8d7f1b60 R08: ffffffff8dee4b02 R09: 0000000000000001 R10: fffff52000000f0a R11: 0000000000086089 R12: ffffffff8d7f1ba4 R13: ffffffff8d7f1b60 R14: ffffffff8d7f1b60 R15: dffffc0000000000 orc_find arch/x86/kernel/unwind_orc.c:173 [inline] unwind_next_frame+0x32a/0x1ce0 arch/x86/kernel/unwind_orc.c:443 arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3270 __alloc_skb+0x215/0x340 net/core/skbuff.c:414 __netdev_alloc_skb+0x73/0x400 net/core/skbuff.c:494 netdev_alloc_skb include/linux/skbuff.h:2881 [inline] dev_alloc_skb include/linux/skbuff.h:2894 [inline] __ieee80211_beacon_get+0x9f7/0x15e0 net/mac80211/tx.c:5151 ieee80211_beacon_get_tim+0x88/0x930 net/mac80211/tx.c:5230 ieee80211_beacon_get include/net/mac80211.h:4992 [inline] mac80211_hwsim_beacon_tx+0x111/0x930 drivers/net/wireless/mac80211_hwsim.c:1808 __iterate_interfaces+0x1e5/0x520 net/mac80211/util.c:793 ieee80211_iterate_active_interfaces_atomic+0x70/0x180 net/mac80211/util.c:829 mac80211_hwsim_beacon+0xcd/0x1c0 drivers/net/wireless/mac80211_hwsim.c:1861 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x609/0xe50 kernel/time/hrtimer.c:1749 hrtimer_run_softirq+0x17b/0x360 kernel/time/hrtimer.c:1766 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_is_held_type+0xff/0x140 kernel/locking/lockdep.c:5685 Code: 00 00 b8 ff ff ff ff 65 0f c1 05 2c e8 c8 76 83 f8 01 75 29 9c 58 f6 c4 02 75 3d 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 ed eb b9 0f 0b 48 RSP: 0018:ffffc90000cf7b80 EFLAGS: 00000292 RAX: 0000000000000046 RBX: 0000000000000003 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffffff8b983960 R08: 0000000000000000 R09: ffffffff8d6fcad7 R10: fffffbfff1adf95a R11: 0000000000000000 R12: ffff888010e79d00 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff888010e7a7b0 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x522/0x720 kernel/locking/lockdep.c:5648 rcu_lock_release include/linux/rcupdate.h:273 [inline] rcu_read_unlock include/linux/rcupdate.h:721 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x86b/0xfa0 net/batman-adv/network-coding.c:723 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 72 4d jb 0x4f 2: 4c 89 e0 mov %r12,%rax 5: 48 29 e8 sub %rbp,%rax 8: 48 89 c2 mov %rax,%rdx b: 48 c1 e8 3f shr $0x3f,%rax f: 48 c1 fa 02 sar $0x2,%rdx 13: 48 01 d0 add %rdx,%rax 16: 48 d1 f8 sar %rax 19: 48 8d 5c 85 00 lea 0x0(%rbp,%rax,4),%rbx 1e: 48 89 d8 mov %rbx,%rax 21: 48 c1 e8 03 shr $0x3,%rax 25: 42 0f b6 14 38 movzbl (%rax,%r15,1),%edx * 2a: 48 89 d8 mov %rbx,%rax <-- trapping instruction 2d: 83 e0 07 and $0x7,%eax 30: 83 c0 03 add $0x3,%eax 33: 38 d0 cmp %dl,%al 35: 7c 04 jl 0x3b 37: 84 d2 test %dl,%dl 39: 75 48 jne 0x83 3b: 48 63 03 movslq (%rbx),%rax 3e: 48 rex.W 3f: 01 .byte 0x1