WARNING in update_load_avg

Status: fixed on 2019/03/20 20:32
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+20fddccabc274e99398e@syzkaller.appspotmail.com
Fix commit: bc6e019b6ee6 fou: Prevent unbounded recursion in GUE error handler also with UDP-Lite
First crash: 2806d, last: 2806d
Cause bisection: introduced by (bisect log) :
commit b8a51b38e4d4dec3e379d52c0fe1a66827f7cf1e
Author: Stefano Brivio <sbrivio@redhat.com>
Date: Thu Nov 8 11:19:23 2018 +0000

  fou, fou6: ICMP error handlers for FoU and GUE

Crash: kernel panic: stack is corrupted in rcu_dynticks_curr_cpu_in_eqs (log)
Repro: C syz .config
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
WARNING in update_load_avg 1 (3) 2019/03/20 13:01

Sample crash report:
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
syz-executor496 (6238) used greatest stack depth: 15648 bytes left
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1015 rq_clock_task kernel/sched/sched.h:1015 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1015 cfs_rq_clock_task kernel/sched/fair.c:4283 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1015 update_load_avg+0x1539/0x2470 kernel/sched/fair.c:3492
==================================================================
BUG: KASAN: stack-out-of-bounds in lookup_object lib/debugobjects.c:157 [inline]
BUG: KASAN: stack-out-of-bounds in debug_object_deactivate+0x3a8/0x450 lib/debugobjects.c:543
Kernel panic - not syncing: panic_on_warn set ...
Read of size 8 at addr ffff8881dae000e0 by task syz-executor496/6371
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.20.0-rc2+ #302

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+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:rq_clock_task kernel/sched/sched.h:1015 [inline]
RIP: 0010:cfs_rq_clock_task kernel/sched/fair.c:4283 [inline]
RIP: 0010:update_load_avg+0x1539/0x2470 kernel/sched/fair.c:3492
Code: e8 fc e1 69 00 e9 8b f8 ff ff 48 8d 7a 18 be ff ff ff ff 48 89 95 30 fb ff ff e8 52 e5 07 00 48 8b 95 30 fb ff ff 85 c0 75 29 <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 f9 48 c1 e9 03 80 3c 01
RSP: 0018:ffff8881daf07238 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8881b3b487c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000086
RBP: ffff8881daf07750 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8881daf2d850 R12: ffff8881bf344bc0
R13: ffff8881daf07728 R14: 0000000000000000 R15: ffff8881b3b48930
 update_blocked_averages+0xcc7/0x1e00 kernel/sched/fair.c:7401
 run_rebalance_domains+0x37c/0x500 kernel/sched/fair.c:9696
 __do_softirq+0x308/0xb7e kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:804
 </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57
Code: e9 2c ff ff ff 48 89 c7 48 89 45 d8 e8 33 22 e6 f9 48 8b 45 d8 e9 ca fe ff ff 48 89 df e8 22 22 e6 f9 eb 82 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90
RSP: 0018:ffff8881d9b27cb8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 1ffff1103b364f9b RCX: 0000000000000000
RDX: 1ffffffff12a3f71 RSI: 0000000000000001 RDI: ffffffff8951fb88
RBP: ffff8881d9b27cb8 R08: ffff8881d9b14340 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d9b27d78
R13: ffffffff8a1640e0 R14: 0000000000000000 R15: 0000000000000001
 arch_safe_halt arch/x86/include/asm/paravirt.h:151 [inline]
 default_idle+0xbf/0x490 arch/x86/kernel/process.c:498
 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489
 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
 cpuidle_idle_call kernel/sched/idle.c:153 [inline]
 do_idle+0x49b/0x5c0 kernel/sched/idle.c:262
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353
 start_secondary+0x487/0x5f0 arch/x86/kernel/smpboot.c:271
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
CPU: 0 PID: 6371 Comm: syz-executor496 Not tainted 4.20.0-rc2+ #302

======================================================
WARNING: possible circular locking dependency detected
4.20.0-rc2+ #302 Not tainted
------------------------------------------------------
swapper/1/0 is trying to acquire lock:
00000000cee8b2f6 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
000000008d358a10 (&rq->lock){-.-.}, at: rq_lock_irqsave kernel/sched/sched.h:1110 [inline]
000000008d358a10 (&rq->lock){-.-.}, at: update_blocked_averages+0x156/0x1e00 kernel/sched/fair.c:7381

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&rq->lock){-.-.}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144
       rq_lock kernel/sched/sched.h:1126 [inline]
       task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9768
       sched_fork+0x443/0xba0 kernel/sched/core.c:2359
       copy_process+0x25b8/0x87a0 kernel/fork.c:1887
       _do_fork+0x1cb/0x11d0 kernel/fork.c:2216
       kernel_thread+0x34/0x40 kernel/fork.c:2275
       rest_init+0x28/0x372 init/main.c:409
       arch_call_rest_init+0xe/0x1b
       start_kernel+0x9f0/0xa2b init/main.c:745
       x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #1 (&p->pi_lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       try_to_wake_up+0xdc/0x1490 kernel/sched/core.c:1965
       wake_up_process+0x10/0x20 kernel/sched/core.c:2129
       __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262
       up+0x13c/0x1c0 kernel/locking/semaphore.c:187
       __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:236
       console_unlock+0x811/0x1190 kernel/printk/printk.c:2432
       vprintk_emit+0x391/0x990 kernel/printk/printk.c:1922
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1997
       check_stack_usage kernel/exit.c:755 [inline]
       do_exit.cold.18+0x57/0x16f kernel/exit.c:916
       do_group_exit+0x177/0x440 kernel/exit.c:970
       __do_sys_exit_group kernel/exit.c:981 [inline]
       __se_sys_exit_group kernel/exit.c:979 [inline]
       __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 ((console_sem).lock){-.-.}:
       lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
       __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219
       console_trylock+0x15/0xa0 kernel/printk/printk.c:2247
       console_trylock_spinning kernel/printk/printk.c:1653 [inline]
       vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1997
       __warn+0x9e/0x1d0 kernel/panic.c:522
       report_bug+0x254/0x2d0 lib/bug.c:186
       fixup_bug arch/x86/kernel/traps.c:178 [inline]
       do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
       do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
       invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
       rq_clock_task kernel/sched/sched.h:1015 [inline]
       cfs_rq_clock_task kernel/sched/fair.c:4283 [inline]
       update_load_avg+0x1539/0x2470 kernel/sched/fair.c:3492
       update_blocked_averages+0xcc7/0x1e00 kernel/sched/fair.c:7401
       run_rebalance_domains+0x37c/0x500 kernel/sched/fair.c:9696
       __do_softirq+0x308/0xb7e kernel/softirq.c:292
       invoke_softirq kernel/softirq.c:373 [inline]
       irq_exit+0x17f/0x1c0 kernel/softirq.c:413
       exiting_irq arch/x86/include/asm/apic.h:536 [inline]
       smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061
       apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:804
       native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57
       arch_safe_halt arch/x86/include/asm/paravirt.h:151 [inline]
       default_idle+0xbf/0x490 arch/x86/kernel/process.c:498
       arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489
       default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
       cpuidle_idle_call kernel/sched/idle.c:153 [inline]
       do_idle+0x49b/0x5c0 kernel/sched/idle.c:262
       cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353
       start_secondary+0x487/0x5f0 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:

Chain exists of:
  (console_sem).lock --> &p->pi_lock --> &rq->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->lock);
                               lock(&p->pi_lock);
                               lock(&rq->lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

1 lock held by swapper/1/0:
 #0: 000000008d358a10 (&rq->lock){-.-.}, at: rq_lock_irqsave kernel/sched/sched.h:1110 [inline]
 #0: 000000008d358a10 (&rq->lock){-.-.}, at: update_blocked_averages+0x156/0x1e00 kernel/sched/fair.c:7381

stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.20.0-rc2+ #302
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+0x244/0x39d lib/dump_stack.c:113
 print_circular_bug.isra.35.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1221
 check_prev_add kernel/locking/lockdep.c:1863 [inline]
 check_prevs_add kernel/locking/lockdep.c:1976 [inline]
 validate_chain kernel/locking/lockdep.c:2347 [inline]
 __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3341
 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
 __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219
 console_trylock+0x15/0xa0 kernel/printk/printk.c:2247
 console_trylock_spinning kernel/printk/printk.c:1653 [inline]
 vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
 printk+0xa7/0xcf kernel/printk/printk.c:1997
 __warn+0x9e/0x1d0 kernel/panic.c:522
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:rq_clock_task kernel/sched/sched.h:1015 [inline]
RIP: 0010:cfs_rq_clock_task kernel/sched/fair.c:4283 [inline]
RIP: 0010:update_load_avg+0x1539/0x2470 kernel/sched/fair.c:3492
Code: e8 fc e1 69 00 e9 8b f8 ff ff 48 8d 7a 18 be ff ff ff ff 48 89 95 30 fb ff ff e8 52 e5 07 00 48 8b 95 30 fb ff ff 85 c0 75 29 <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 f9 48 c1 e9 03 80 3c 01
RSP: 0018:ffff8881daf07238 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8881b3b487c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000086
RBP: ffff8881daf07750 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8881daf2d850 R12: ffff8881bf344bc0
R13: ffff8881daf07728 R14: 0000000000000000 R15: ffff8881b3b48930
 update_blocked_averages+0xcc7/0x1e00 kernel/sched/fair.c:7401
 run_rebalance_domains+0x37c/0x500 kernel/sched/fair.c:9696
 __do_softirq+0x308/0xb7e kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061
 ? inte
Lost 38 message(s)!
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:

The buggy address belongs to the page:
page:ffffea00076b8000 count:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000001000(reserved)
raw: 02fffc0000001000 ffffea00076b8008 ffffea00076b8008 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881dadfff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881dae00000: 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1
>ffff8881dae00080: f1 00 f2 f2 f2 f2 f2 f2 f2 f8 f2 f2 f2 00 00 00
                                                       ^
 ffff8881dae00100: 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1
 ffff8881dae00180: f1 f8 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00
==================================================================
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 6371 Comm: syz-executor496 Tainted: G    B             4.20.0-rc2+ #302
Shutting down cpus with NMI

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/11/19 01:32 net-next-old cddaf02bcb73 adf636a8 .config console log report syz C ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.