IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready ====================================================== WARNING: possible circular locking dependency detected 4.19.189-syzkaller #0 Not tainted ------------------------------------------------------ swapper/0/0 is trying to acquire lock: 0000000003e0fbc5 (slock-AF_INET6){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 0000000003e0fbc5 (slock-AF_INET6){+.-.}, at: sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680 but task is already holding lock: 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: spin_lock_bh include/linux/spinlock.h:334 [inline] 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: sctp_addr_wq_timeout_handler+0x38/0x550 net/sctp/protocol.c:640 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}: spin_lock_bh include/linux/spinlock.h:334 [inline] sctp_destroy_sock+0x234/0x480 net/sctp/socket.c:4811 sctp_v6_destroy_sock+0x11/0x20 net/sctp/socket.c:8973 sk_common_release+0x64/0x2d0 net/core/sock.c:3093 sctp_close+0x46d/0x800 net/sctp/socket.c:1580 inet_release+0xd7/0x1e0 net/ipv4/af_inet.c:427 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:472 __sock_release+0xcd/0x2a0 net/socket.c:579 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (slock-AF_INET6){+.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680 call_timer_fn+0x177/0x700 kernel/time/timer.c:1338 expire_timers+0x243/0x4e0 kernel/time/timer.c:1375 __run_timers kernel/time/timer.c:1696 [inline] run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709 __do_softirq+0x265/0x980 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x215/0x260 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x49/0x310 arch/x86/kernel/process.c:557 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263 cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369 start_kernel+0x8d6/0x911 init/main.c:736 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&net->sctp.addr_wq_lock)->rlock); lock(slock-AF_INET6); lock(&(&net->sctp.addr_wq_lock)->rlock); lock(slock-AF_INET6); *** DEADLOCK *** 2 locks held by swapper/0/0: #0: 000000009aa23dc6 ((&net->sctp.addr_wq_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] #0: 000000009aa23dc6 ((&net->sctp.addr_wq_timer)){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1328 #1: 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: spin_lock_bh include/linux/spinlock.h:334 [inline] #1: 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: sctp_addr_wq_timeout_handler+0x38/0x550 net/sctp/protocol.c:640 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680 call_timer_fn+0x177/0x700 kernel/time/timer.c:1338 expire_timers+0x243/0x4e0 kernel/time/timer.c:1375 __run_timers kernel/time/timer.c:1696 [inline] run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709 __do_softirq+0x265/0x980 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x215/0x260 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: 48 89 df e8 a4 36 80 f9 e9 2e ff ff ff 48 89 df e8 97 36 80 f9 eb 82 90 90 90 90 90 e9 07 00 00 00 0f 00 2d b4 9a 4f 00 fb f4 90 e9 07 00 00 00 0f 00 2d a4 9a 4f 00 f4 c3 90 90 41 56 41 55 RSP: 0018:ffffffff89e07d40 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff13e304c RBX: dffffc0000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffff89e78904 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89f18250 R13: 1ffffffff13c0fb2 R14: 0000000000000000 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x49/0x310 arch/x86/kernel/process.c:557 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263 cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369 start_kernel+0x8d6/0x911 init/main.c:736 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options devpts: called with bogus options netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. devpts: called with bogus options netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. IPv6: ADDRCONF(NETDEV_UP): veth3: link is not ready netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. devpts: called with bogus options netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. IPv6: ADDRCONF(NETDEV_UP): veth3: link is not ready netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. IPv6: ADDRCONF(NETDEV_UP): veth5: link is not ready netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. IPv6: ADDRCONF(NETDEV_UP): veth5: link is not ready netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. IPv6: ADDRCONF(NETDEV_UP): veth7: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth7: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth9: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth11: link is not ready