====================================================== WARNING: possible circular locking dependency detected 4.19.143-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/16271 is trying to acquire lock: 000000000abce012 (&qdisc_tx_lock){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 000000000abce012 (&qdisc_tx_lock){+.-.}, at: red_adaptative_timer+0x92/0x5c0 net/sched/sch_red.c:265 but task is already holding lock: 000000005aec4183 ((&q->adapt_timer)#2){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] 000000005aec4183 ((&q->adapt_timer)#2){+.-.}, 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)#2){+.-.}: 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((&q->adapt_timer)#2); lock(&qdisc_tx_lock); lock((&q->adapt_timer)#2); lock(&qdisc_tx_lock); *** DEADLOCK *** 1 lock held by syz-executor.3/16271: #0: 000000005aec4183 ((&q->adapt_timer)#2){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] #0: 000000005aec4183 ((&q->adapt_timer)#2){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1328 stack backtrace: CPU: 0 PID: 16271 Comm: syz-executor.3 Not tainted 4.19.143-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: 0033:0x45ba85 Code: 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 84 cf fb ff c3 48 83 ec 08 e8 ea 46 00 00 48 89 04 24 b8 23 00 00 00 0f 05 48 8b 3c 24 <48> 89 c2 e8 33 47 00 00 48 89 d0 48 83 c4 08 48 3d 01 f0 ff ff 0f RSP: 002b:00007fffc7c03f20 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 00000000002dedea RCX: 000000000045ba81 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 00000000aa705f27 R09: 00000000aa705f2b R10: 00007fffc7c04030 R11: 0000000000000293 R12: 000000000118cf40 R13: 000000000118d940 R14: ffffffffffffffff R15: 000000000118cfec nla_parse: 46 callbacks suppressed netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. nla_parse: 38 callbacks suppressed netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'.