syzbot


BUG: soft lockup in fq_pie_timer (4)

Status: fixed on 2023/10/12 12:48
Subsystems: net
[Documentation on labels]
Fix commit: 8c21ab1bae94 net/sched: fq_pie: avoid stalls in fq_pie_timer()
First crash: 268d, last: 217d
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 BUG: soft lockup in fq_pie_timer (2) origin:upstream C inconclusive 4 115d 232d 0/3 upstream: reported C repro on 2023/08/29 01:49
upstream INFO: rcu detected stall in fq_pie_timer net C error 35 811d 1028d 20/26 fixed on 2022/03/08 16:11
linux-5.15 INFO: rcu detected stall in fq_pie_timer origin:lts-only C done 23 239d 330d 0/3 upstream: reported C repro on 2023/05/22 23:26
linux-6.1 BUG: soft lockup in fq_pie_timer C done 7 311d 319d 3/3 fixed on 2023/07/22 07:09
upstream BUG: soft lockup in fq_pie_timer (2) net C error done 3 357d 423d 0/26 closed as invalid on 2023/05/26 05:46
upstream BUG: soft lockup in fq_pie_timer net C error error 10 553d 590d 0/26 closed as invalid on 2022/11/18 11:06
upstream INFO: rcu detected stall in fq_pie_timer (2) net C done 1 69d 111d 0/26 upstream: reported C repro on 2023/12/27 13:54

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [swapper/1:0]
Modules linked in:
irq event stamp: 1226673
hardirqs last  enabled at (1226672): [<ffff80008a65a4e4>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last  enabled at (1226672): [<ffff80008a65a4e4>] _raw_spin_unlock_irq+0x30/0x80 kernel/locking/spinlock.c:202
hardirqs last disabled at (1226673): [<ffff80008a56bf4c>] __el1_irq arch/arm64/kernel/entry-common.c:499 [inline]
hardirqs last disabled at (1226673): [<ffff80008a56bf4c>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:517
softirqs last  enabled at (1160478): [<ffff8000800218ec>] softirq_handle_end kernel/softirq.c:399 [inline]
softirqs last  enabled at (1160478): [<ffff8000800218ec>] __do_softirq+0xac0/0xd54 kernel/softirq.c:582
softirqs last disabled at (1160563): [<ffff80008002aad4>] ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.5.0-rc5-syzkaller-g6f09e57d8cf6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : check_kcov_mode kernel/kcov.c:173 [inline]
pc : write_comp_data kernel/kcov.c:236 [inline]
pc : __sanitizer_cov_trace_const_cmp8+0x3c/0x90 kernel/kcov.c:311
lr : pie_calculate_probability+0x57c/0x7bc net/sched/sch_pie.c:410
sp : ffff800080017b30
x29: ffff800080017b70 x28: fffffff0a3da8872 x27: fffffff0a3da8872
x26: dfff800000000000 x25: ffff80009fdd90f0 x24: ffff80009fdd910c
x23: 1fffe0001a77c263 x22: 0000000000000000 x21: 0000000000000000
x20: ffff0000d3be131a x19: ffff80009fdd90d0 x18: dfff800000000000
x17: 0000000000420042 x16: ffff800080516968 x15: ffff700010002f60
x14: 1ffff00010002f60 x13: 0000000000000004 x12: ffffffffffffffff
x11: 0000000000000102 x10: 0000000000000100 x9 : 0000000000000102
x8 : ffff0000c19b9bc0 x7 : ffff800088a7d948 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008032ff28
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 check_kcov_mode kernel/kcov.c:173 [inline]
 write_comp_data kernel/kcov.c:236 [inline]
 __sanitizer_cov_trace_const_cmp8+0x3c/0x90 kernel/kcov.c:311
 fq_pie_timer+0x1f0/0x41c net/sched/sch_fq_pie.c:387
 call_timer_fn+0x19c/0x8cc kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x55c/0x734 kernel/time/timer.c:2022
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:2035
 __do_softirq+0x2d0/0xd54 kernel/softirq.c:553
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:882
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:434 [inline]
 __irq_exit_rcu+0x200/0x494 kernel/softirq.c:632
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:644
 __el1_irq arch/arm64/kernel/entry-common.c:503 [inline]
 el1_interrupt+0x38/0x68 arch/arm64/kernel/entry-common.c:517
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:522
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:587
 __daif_local_irq_enable arch/arm64/include/asm/irqflags.h:33 [inline]
 arch_local_irq_enable+0x8/0xc arch/arm64/include/asm/irqflags.h:55
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1f0/0x4e8 kernel/sched/idle.c:282
 cpu_startup_entry+0x24/0x28 kernel/sched/idle.c:379
 secondary_start_kernel+0x198/0x1c0 arch/arm64/kernel/smp.c:264
 __secondary_switched+0xb8/0xbc arch/arm64/kernel/head.S:681

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/13 21:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 6f09e57d8cf6 39990d51 .config console log report syz [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in fq_pie_timer
2023/07/24 04:18 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e40939bbfc68 27cbe77f .config console log report syz [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in fq_pie_timer
2023/09/12 06:56 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci fe4469582053 59da8366 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in fq_pie_timer
2023/08/13 19:13 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 6f09e57d8cf6 39990d51 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in fq_pie_timer
2023/07/24 01:12 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e40939bbfc68 27cbe77f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in fq_pie_timer
* Struck through repros no longer work on HEAD.