ci starts bisection 2023-04-21 08:23:08.134323024 +0000 UTC m=+79982.916983158 bisecting fixing commit since 2faac9a98f010cf5b342fa89ac489c4586364e6e building syzkaller on 8b4eb097b2e5a6f78a8d0b1ae48de4bbaa4c45a1 ensuring issue is reproducible on original commit 2faac9a98f010cf5b342fa89ac489c4586364e6e testing commit 2faac9a98f010cf5b342fa89ac489c4586364e6e gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 2b63de7e58ae2231373171914f9be503df9777a3958ec98423d4054c01662b3e all runs: crashed: possible deadlock in br_multicast_rcv testing current HEAD 2af3e53a4dc08657f1b46f97f04ff4a0ab3cad8d testing commit 2af3e53a4dc08657f1b46f97f04ff4a0ab3cad8d gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 11344d9197188ff72516db4f0ba33ea7988e2c0e53ad530b176d63d8211444aa all runs: crashed: possible deadlock in br_multicast_rcv revisions tested: 2, total time: 52m16.841201874s (build: 45m25.837137785s, test: 6m25.09214847s) the crash still happens on HEAD commit msg: Merge tag 'drm-fixes-2023-04-21' of git://anongit.freedesktop.org/drm/drm crash: possible deadlock in br_multicast_rcv ============================================ WARNING: possible recursive locking detected 6.3.0-rc7-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/5478 is trying to acquire lock: ffff888029a29338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff888029a29338 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip4_multicast_query net/bridge/br_multicast.c:3435 [inline] ffff888029a29338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv4_rcv net/bridge/br_multicast.c:3849 [inline] ffff888029a29338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0xaa4/0x5e40 net/bridge/br_multicast.c:3965 but task is already holding lock: ffff8880235e5338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff8880235e5338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x5d/0x2c0 net/bridge/br_multicast.c:1900 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 5 locks held by syz-executor.0/5478: #0: ffffc90000007d78 ((&pmctx->ip4_own_query.timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:31 [inline] #0: ffffc90000007d78 ((&pmctx->ip4_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xcd/0x400 kernel/time/timer.c:1690 #1: ffff8880235e5338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #1: ffff8880235e5338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x5d/0x2c0 net/bridge/br_multicast.c:1900 #2: ffffffff8b78b360 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x206/0x31d0 net/core/dev.c:4164 #3: ffffffff8b78b360 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x206/0x31d0 net/core/dev.c:4164 #4: ffffffff8b78b3c0 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x4/0x1260 net/bridge/br_device.c:29 stack backtrace: CPU: 0 PID: 5478 Comm: syz-executor.0 Not tainted 6.3.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x64/0xb0 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2991 [inline] check_deadlock kernel/locking/lockdep.c:3034 [inline] validate_chain kernel/locking/lockdep.c:3819 [inline] __lock_acquire+0x1362/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 __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:350 [inline] br_ip4_multicast_query net/bridge/br_multicast.c:3435 [inline] br_multicast_ipv4_rcv net/bridge/br_multicast.c:3849 [inline] br_multicast_rcv+0xaa4/0x5e40 net/bridge/br_multicast.c:3965 br_dev_xmit+0x60b/0x1260 net/bridge/br_device.c:89 __netdev_start_xmit include/linux/netdevice.h:4884 [inline] netdev_start_xmit include/linux/netdevice.h:4898 [inline] xmit_one net/core/dev.c:3581 [inline] dev_hard_start_xmit+0x153/0x580 net/core/dev.c:3597 __dev_queue_xmit+0x249e/0x31d0 net/core/dev.c:4247 dev_queue_xmit include/linux/netdevice.h:3054 [inline] vlan_dev_hard_start_xmit+0x178/0x550 net/8021q/vlan_dev.c:124 __netdev_start_xmit include/linux/netdevice.h:4884 [inline] netdev_start_xmit include/linux/netdevice.h:4898 [inline] xmit_one net/core/dev.c:3581 [inline] dev_hard_start_xmit+0x153/0x580 net/core/dev.c:3597 __dev_queue_xmit+0x249e/0x31d0 net/core/dev.c:4247 dev_queue_xmit include/linux/netdevice.h:3054 [inline] br_dev_queue_push_xmit+0x1df/0x660 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:302 [inline] __br_multicast_send_query+0x23cb/0x43c0 net/bridge/br_multicast.c:1804 br_multicast_send_query+0x1ef/0x3e0 net/bridge/br_multicast.c:1883 br_multicast_port_query_expired+0x22b/0x2c0 net/bridge/br_multicast.c:1908 call_timer_fn+0x163/0x400 kernel/time/timer.c:1700 expire_timers+0x224/0x400 kernel/time/timer.c:1751 __run_timers kernel/time/timer.c:2022 [inline] __run_timers kernel/time/timer.c:1995 [inline] run_timer_softirq+0x296/0x790 kernel/time/timer.c:2035 __do_softirq+0x1d4/0x905 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:kmap_local_sched_in kernel/sched/core.c:5091 [inline] RIP: 0010:finish_task_switch.isra.0+0x2bf/0xc30 kernel/sched/core.c:5194 Code: 8b 3a 4c 89 e7 48 c7 02 00 00 00 00 ff d1 4d 85 ff 75 bf 4c 89 e7 e8 60 f8 ff ff e8 ab c3 2c 00 fb 65 48 8b 1c 25 00 b8 03 00 <48> 8d bb 88 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90004f3fa98 EFLAGS: 00000206 RAX: 000000000006625f RBX: ffff88801f64d700 RCX: 1ffffffff1acc399 RDX: 0000000000000000 RSI: ffffffff896b94e0 RDI: ffffffff89c25f60 RBP: ffffc90004f3fae0 R08: 0000000000000001 R09: 0000000000000001 R10: fffffbfff1acc9a2 R11: 0000000000000000 R12: ffff8880b9a3c200 R13: ffff888076929d00 R14: 0000000000000000 R15: ffff8880b9a3cc38 context_switch kernel/sched/core.c:5310 [inline] __schedule+0xc59/0x5720 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 do_nanosleep+0x145/0x450 kernel/time/hrtimer.c:2044 hrtimer_nanosleep+0x15c/0x350 kernel/time/hrtimer.c:2097 common_nsleep+0x78/0xc0 kernel/time/posix-timers.c:1236 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1277 [inline] __se_sys_clock_nanosleep kernel/time/posix-timers.c:1254 [inline] __x64_sys_clock_nanosleep+0x290/0x410 kernel/time/posix-timers.c:1254 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f00544b0e21 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 aa e7 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 e3 e7 ff ff 48 8b 04 24 eb 97 66 2e 0f 1f RSP: 002b:00007ffc5ea0e350 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 000000000000006a RCX: 00007f00544b0e21 RDX: 00007ffc5ea0e390 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffc5ea0e41c R08: 0000000000000000 R09: 00007ffc5ebd2080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032 R13: 000000000000c8ce R14: 000000000000000d R15: 00007ffc5ea0e480 ---------------- Code disassembly (best guess): 0: 8b 3a mov (%rdx),%edi 2: 4c 89 e7 mov %r12,%rdi 5: 48 c7 02 00 00 00 00 movq $0x0,(%rdx) c: ff d1 callq *%rcx e: 4d 85 ff test %r15,%r15 11: 75 bf jne 0xffffffd2 13: 4c 89 e7 mov %r12,%rdi 16: e8 60 f8 ff ff callq 0xfffff87b 1b: e8 ab c3 2c 00 callq 0x2cc3cb 20: fb sti 21: 65 48 8b 1c 25 00 b8 mov %gs:0x3b800,%rbx 28: 03 00 * 2a: 48 8d bb 88 15 00 00 lea 0x1588(%rbx),%rdi <-- trapping instruction 31: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 38: fc ff df 3b: 48 89 fa mov %rdi,%rdx 3e: 48 rex.W 3f: c1 .byte 0xc1