possible deadlock in pie

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	possible deadlock in pie_timer (2) net				2	308d	308d	23/26	fixed on 2023/09/28 17:51
upstream	possible deadlock in pie_timer net	C	done		2	1671d	1672d	13/26	fixed on 2019/10/15 23:40
linux-6.1	possible deadlock in pie_timer				1	268d	268d	0/3	auto-obsoleted due to no activity on 2023/11/10 02:26
linux-4.14	possible deadlock in pie_timer	C		inconclusive	3	802d	1663d	0/1	upstream: reported C repro on 2019/10/06 16:17

====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ swapper/1/0 is trying to acquire lock: 00000000eeabeb81 (&qdisc_rx_lock){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 00000000eeabeb81 (&qdisc_rx_lock){+.-.}, at: pie_timer+0x92/0x740 net/sched/sch_pie.c:433 but task is already holding lock: 000000006bcb8190 ((&q->adapt_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] 000000006bcb8190 ((&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)){+.-.}: qdisc_destroy+0x180/0x790 net/sched/sch_generic.c:983 sfb_change+0x2c9/0xb30 net/sched/sch_sfb.c:527 qdisc_change net/sched/sch_api.c:1240 [inline] tc_modify_qdisc+0xf6a/0x1a80 net/sched/sch_api.c:1543 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline] netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227 __sys_sendmsg net/socket.c:2265 [inline] __do_sys_sendmsg net/socket.c:2274 [inline] __se_sys_sendmsg net/socket.c:2272 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&qdisc_rx_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] pie_timer+0x92/0x740 net/sched/sch_pie.c:433 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:536 [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_secondary+0x435/0x5c0 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_rx_lock); lock((&q->adapt_timer)); lock(&qdisc_rx_lock); *** DEADLOCK *** 1 lock held by swapper/1/0: #0: 000000006bcb8190 ((&q->adapt_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline] #0: 000000006bcb8190 ((&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 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __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] pie_timer+0x92/0x740 net/sched/sch_pie.c:433 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:536 [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 </IRQ> RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: 48 89 df e8 f4 20 7f f9 e9 2e ff ff ff 48 89 df e8 e7 20 7f f9 eb 82 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 14 43 4e 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d 04 43 4e 00 f4 c3 90 90 41 56 41 55 RSP: 0018:ffff8880b5a9fd40 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff13e3054 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5a86c44 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89f18290 R13: 1ffff11016b53fb2 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+0x435/0x5c0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 ---------------- Code disassembly (best guess): 0: 48 89 df mov %rbx,%rdi 3: e8 f4 20 7f f9 callq 0xf97f20fc 8: e9 2e ff ff ff jmpq 0xffffff3b d: 48 89 df mov %rbx,%rdi 10: e8 e7 20 7f f9 callq 0xf97f20fc 15: eb 82 jmp 0xffffff99 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: e9 07 00 00 00 jmpq 0x28 21: 0f 00 2d 14 43 4e 00 verw 0x4e4314(%rip) # 0x4e433c 28: fb sti 29: f4 hlt * 2a: c3 retq <-- trapping instruction 2b: 90 nop 2c: e9 07 00 00 00 jmpq 0x38 31: 0f 00 2d 04 43 4e 00 verw 0x4e4304(%rip) # 0x4e433c 38: f4 hlt 39: c3 retq 3a: 90 nop 3b: 90 nop 3c: 41 56 push %r14 3e: 41 55 push %r13