blktrace: Concurrent blktraces are not allowed on loop0 ====================================================== WARNING: possible circular locking dependency detected 4.19.140-syzkaller #0 Not tainted ------------------------------------------------------ swapper/1/0 is trying to acquire lock: 0000000033f0fcbe (&qdisc_tx_lock){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 0000000033f0fcbe (&qdisc_tx_lock){+.-.}, at: red_adaptative_timer+0x92/0x5c0 net/sched/sch_red.c:265 but task is already holding lock: 000000007f2920bd ((&q->adapt_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] 000000007f2920bd ((&q->adapt_timer)){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1328 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 ((&q->adapt_timer)){+.-.}: red_destroy+0x15/0x60 net/sched/sch_red.c:182 qdisc_destroy+0x180/0x780 net/sched/sch_generic.c:983 red_change+0x514/0x1080 net/sched/sch_red.c:236 qdisc_change net/sched/sch_api.c:1239 [inline] tc_modify_qdisc+0xf6a/0x1a80 net/sched/sch_api.c:1542 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x6bb/0xc40 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:632 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2115 __sys_sendmsg net/socket.c:2153 [inline] __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2160 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&qdisc_tx_lock){+.-.}: __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] red_adaptative_timer+0x92/0x5c0 net/sched/sch_red.c:265 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:1703 [inline] run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1716 __do_softirq+0x26c/0x9a0 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:544 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094 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_secondary+0x41f/0x580 arch/x86/kernel/smpboot.c:271 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((&q->adapt_timer)); lock(&qdisc_tx_lock); lock((&q->adapt_timer)); lock(&qdisc_tx_lock); *** DEADLOCK *** 1 lock held by swapper/1/0: #0: 000000007f2920bd ((&q->adapt_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] #0: 000000007f2920bd ((&q->adapt_timer)){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1328 stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.19.140-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/0x2fe lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3415 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907 __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] red_adaptative_timer+0x92/0x5c0 net/sched/sch_red.c:265 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:1703 [inline] run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1716 __do_softirq+0x26c/0x9a0 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:544 [inline] smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094 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 34 6e 62 fa e9 2e ff ff ff 48 89 df e8 27 6e 62 fa eb 82 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 34 89 4a 00 fb f4 90 e9 07 00 00 00 0f 00 2d 24 89 4a 00 f4 c3 90 90 41 56 41 55 RSP: 0018:ffff8880a9f4fd58 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11a4b6c RBX: dffffc0000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880a9f3cc44 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff88d25b50 R13: 1ffff110153e9fb5 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_secondary+0x41f/0x580 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 netlink: 268 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 268 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 268 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 268 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 'syz-executor.2': attribute type 3 has an invalid length. netlink: 'syz-executor.2': attribute type 3 has an invalid length.