syzbot


INFO: rcu detected stall in uinput_write

Status: fixed on 2023/10/12 12:47
Subsystems: input
[Documentation on labels]
Fix commit: 8c21ab1bae94 net/sched: fq_pie: avoid stalls in fq_pie_timer()
First crash: 301d, last: 301d

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2674 jiffies s: 54465 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 21016 Comm: syz-executor.0 Not tainted 6.5.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:pie_calculate_probability+0x206/0x850 net/sched/sch_pie.c:340
Code: 44 24 10 4c 89 e8 48 29 c8 48 89 44 24 18 48 b8 98 99 99 99 99 99 19 00 48 89 c7 e8 64 0e 2e f9 48 b8 98 99 99 99 99 99 19 00 <4c> 39 f8 0f 82 06 03 00 00 e8 bc 12 2e f9 49 c1 ec 05 4c 89 fe 49
RSP: 0018:ffffc90000007bc0 EFLAGS: 00000246
RAX: 0019999999999998 RBX: ffffc90019948f90 RCX: ffffffff88585ddc
RDX: ffff8880455fbb80 RSI: 0000000000000100 RDI: 0000000000000007
RBP: ffff888076e6f300 R08: 0000000000000007 R09: 0019999999999998
R10: 0000000000000000 R11: 0000000079118bec R12: 00000015798ee228
R13: 0000000000000000 R14: 0000000225c17d04 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7efab40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000200ab000 CR3: 00000000467f7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 fq_pie_timer+0x1da/0x4f0 net/sched/sch_fq_pie.c:387
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x764/0xb10 kernel/time/timer.c:2022
 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035
 __do_softirq+0x218/0x965 kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1109
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 e6 e8 31 f7 48 89 df e8 9e 61 32 f7 f7 c5 00 02 00 00 75 1f 9c 58 f6 c4 02 75 2f <bf> 01 00 00 00 e8 65 0a 24 f7 65 8b 05 56 29 ce 75 85 c0 74 12 5b
RSP: 0018:ffffc9000499fbe8 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88807aea9218 RCX: 1ffffffff231b212
RDX: 0000000000000000 RSI: ffffffff8a6c76e0 RDI: ffffffff8ac80620
RBP: 0000000000000246 R08: 0000000000000001 R09: fffffbfff23093fb
R10: ffffffff91849fdf R11: ffffffff90f11d60 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000246 R15: ffff88807aea9218
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 input_event drivers/input/input.c:436 [inline]
 input_event+0x8e/0xa0 drivers/input/input.c:427
 uinput_inject_events drivers/input/misc/uinput.c:625 [inline]
 uinput_write+0xc72/0x12d0 drivers/input/misc/uinput.c:647
 vfs_write+0x2a4/0xe40 fs/read_write.c:582
 ksys_write+0x1f0/0x250 fs/read_write.c:637
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7f20579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7efa5ac EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000600
RDX: 00000000fffffd6d RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/07/24 11:56 upstream 6eaae1980760 06460670 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: rcu detected stall in uinput_write
* Struck through repros no longer work on HEAD.