syzbot


INFO: rcu detected stall in redirected_tty_write

Status: auto-obsoleted due to no activity on 2025/04/01 11:39
Subsystems: serial
[Documentation on labels]
First crash: 92d, last: 92d

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...0: (1 GPs behind) idle=b82c/1/0x4000000000000000 softirq=79032/79036 fqs=2098
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        0          0            0
rcu: 	cputime:        0          0            0   ==> 52500(ms)
rcu: 	(detected by 0, t=10505 jiffies, g=82193, q=3030 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5174 Comm: syslogd Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:__lock_acquire+0x79/0x3c40 kernel/locking/lockdep.c:5077
Code: 24 10 48 8d 84 24 90 00 00 00 48 c1 e8 03 48 89 44 24 18 48 89 c6 48 b8 00 00 00 00 00 fc ff df 48 8d 14 06 c7 02 f1 f1 f1 f1 <c7> 42 04 00 f3 f3 f3 65 48 8b 14 25 28 00 00 00 48 89 94 24 e8 00
RSP: 0018:ffffc90000a18b38 EFLAGS: 00000802
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: fffff52000143179 RSI: 1ffff92000143179 RDI: ffff88802eb3a300
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff905f36d7 R11: 0000000000000004 R12: ffff88802eb3a300
R13: ffff88802eb3a300 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f8ea1ee0500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3410e9 CR3: 0000000035ef8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 advance_sched+0xd8/0xc60 net/sched/sch_taprio.c:924
 __run_hrtimer kernel/time/hrtimer.c:1739 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1803
 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1865
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 71 4a f6 48 89 df e8 ae f0 4a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 95 d5 3b f6 65 8b 05 f6 90 d7 74 85 c0 74 16 5b
RSP: 0018:ffffc900049b7b08 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88814d6c5508 RCX: 1ffffffff2dd2911
RDX: 0000000000000000 RSI: ffffffff8b6cd9e0 RDI: ffffffff8bd1ede0
RBP: 0000000000000246 R08: 0000000000000001 R09: fffffbfff2dca3ad
R10: ffffffff96e51d6f R11: 0000000000000003 R12: ffff88814d6c5000
R13: dffffc0000000000 R14: 0000000000000051 R15: ffff88814d6c5000
 n_tty_write+0x1e9/0x1140 drivers/tty/n_tty.c:2377
 iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
 file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
 tty_write drivers/tty/tty_io.c:1111 [inline]
 redirected_tty_write drivers/tty/tty_io.c:1134 [inline]
 redirected_tty_write+0xcc/0x140 drivers/tty/tty_io.c:1114
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x5ae/0x1150 fs/read_write.c:679
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ea2034bf2
Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fff75d64408 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8ea2034bf2
RDX: 0000000000000051 RSI: 000055f4cdd95600 RDI: 0000000000000003
RBP: 000055f4cdd95600 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000051
R13: 00007f8ea1ee0480 R14: 0000000000000003 R15: 000055f4cdd95410
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/01 11:34 upstream ccb98ccef0e5 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in redirected_tty_write
* Struck through repros no longer work on HEAD.