IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready ====================================================== WARNING: possible circular locking dependency detected 4.14.240-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/8215 is trying to acquire lock: (&cpuctx_mutex/1){+.+.}, at: [] mutex_lock_double kernel/events/core.c:9933 [inline] (&cpuctx_mutex/1){+.+.}, at: [] __perf_event_ctx_lock_double kernel/events/core.c:9992 [inline] (&cpuctx_mutex/1){+.+.}, at: [] SYSC_perf_event_open kernel/events/core.c:10254 [inline] (&cpuctx_mutex/1){+.+.}, at: [] SyS_perf_event_open+0xd28/0x24b0 kernel/events/core.c:10012 but task is already holding lock: (&cpuctx_mutex){+.+.}, at: [] mutex_lock_double kernel/events/core.c:9932 [inline] (&cpuctx_mutex){+.+.}, at: [] __perf_event_ctx_lock_double kernel/events/core.c:9992 [inline] (&cpuctx_mutex){+.+.}, at: [] SYSC_perf_event_open kernel/events/core.c:10254 [inline] (&cpuctx_mutex){+.+.}, at: [] SyS_perf_event_open+0xd1b/0x24b0 kernel/events/core.c:10012 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&cpuctx_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_event_init_cpu+0xb7/0x170 kernel/events/core.c:11252 perf_event_init+0x2cc/0x308 kernel/events/core.c:11299 start_kernel+0x46a/0x770 init/main.c:620 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #1 (pmus_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 swevent_hlist_get kernel/events/core.c:7925 [inline] perf_swevent_init+0x11e/0x4b0 kernel/events/core.c:7985 perf_try_init_event+0xdf/0x1f0 kernel/events/core.c:9371 perf_init_event kernel/events/core.c:9409 [inline] perf_event_alloc.part.0+0xe2d/0x2640 kernel/events/core.c:9669 perf_event_alloc kernel/events/core.c:10022 [inline] SYSC_perf_event_open kernel/events/core.c:10126 [inline] SyS_perf_event_open+0x67f/0x24b0 kernel/events/core.c:10012 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&cpuctx_mutex/1){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 mutex_lock_double kernel/events/core.c:9933 [inline] __perf_event_ctx_lock_double kernel/events/core.c:9992 [inline] SYSC_perf_event_open kernel/events/core.c:10254 [inline] SyS_perf_event_open+0xd28/0x24b0 kernel/events/core.c:10012 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &cpuctx_mutex/1 --> pmus_lock --> &cpuctx_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cpuctx_mutex); lock(pmus_lock); lock(&cpuctx_mutex); lock(&cpuctx_mutex/1); *** DEADLOCK *** 1 lock held by syz-executor.0/8215: #0: (&cpuctx_mutex){+.+.}, at: [] mutex_lock_double kernel/events/core.c:9932 [inline] #0: (&cpuctx_mutex){+.+.}, at: [] __perf_event_ctx_lock_double kernel/events/core.c:9992 [inline] #0: (&cpuctx_mutex){+.+.}, at: [] SYSC_perf_event_open kernel/events/core.c:10254 [inline] #0: (&cpuctx_mutex){+.+.}, at: [] SyS_perf_event_open+0xd1b/0x24b0 kernel/events/core.c:10012 stack backtrace: CPU: 1 PID: 8215 Comm: syz-executor.0 Not tainted 4.14.240-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 mutex_lock_double kernel/events/core.c:9933 [inline] __perf_event_ctx_lock_double kernel/events/core.c:9992 [inline] SYSC_perf_event_open kernel/events/core.c:10254 [inline] SyS_perf_event_open+0xd28/0x24b0 kernel/events/core.c:10012 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4665e9 RSP: 002b:00007f6420f67188 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00000000200000c0 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffd4dfe270f R14: 00007f6420f67300 R15: 0000000000022000