syzbot


INFO: rcu detected stall in generic_file_write_iter (6)

Status: closed as invalid on 2022/02/08 09:50
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 339d, last: 282d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in generic_file_write_iter (3) 1 1029d 1029d 0/24 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in generic_file_write_iter (2) 2 1244d 1283d 0/24 auto-closed as invalid on 2019/10/25 09:01
upstream INFO: rcu detected stall in generic_file_write_iter (4) 1 962d 958d 0/24 auto-closed as invalid on 2020/05/09 11:43
upstream INFO: rcu detected stall in generic_file_write_iter 58 1308d 1450d 0/24 closed as dup on 2018/10/27 15:28
upstream INFO: rcu detected stall in generic_file_write_iter (5) 2 797d 804d 0/24 auto-closed as invalid on 2020/10/22 01:02

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P148/1:b..l P8282/1:b..l
	(detected by 1, t=10502 jiffies, g=152305, q=39)
task:syz-executor.4  state:R  running task     stack:23984 pid: 8282 ppid: 12097 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6287
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6687
 irqentry_exit+0x56/0x90 kernel/entry/common.c:425
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:mem_cgroup_from_task+0xa9/0x100 mm/memcontrol.c:871
Code: 3d 8d 99 ff 85 c0 74 23 48 83 c3 20 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 6f 44 fb ff 48 8b 03 5b 41 5e 41 5f <c3> e8 41 bc 26 08 85 c0 74 d4 80 3d cf bb f4 0b 00 75 cb c6 05 c6
RSP: 0018:ffffc900032cf6c8 EFLAGS: 00000246
RAX: ffff888140154000 RBX: ffff88807e0d3900 RCX: 0000000080000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffea000282bdc0 R08: dffffc0000000000 R09: ffffed10173a64a2
R10: ffffed10173a64a2 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff11010575a5a R14: ffff888082bad2d0 R15: 0000000000000000
 get_mem_cgroup_from_mm+0xa4/0x350 mm/memcontrol.c:923
 __mem_cgroup_charge+0x12/0x80 mm/memcontrol.c:6723
 mem_cgroup_charge include/linux/memcontrol.h:694 [inline]
 shmem_add_to_page_cache+0xc0b/0x1720 mm/shmem.c:713
 shmem_getpage_gfp+0x18e0/0x3320 mm/shmem.c:1935
 shmem_getpage mm/shmem.c:151 [inline]
 shmem_write_begin+0xcf/0x1a0 mm/shmem.c:2469
 generic_perform_write+0x2dd/0x600 mm/filemap.c:3770
 __generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3897
 generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3929
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xb11/0xe90 fs/read_write.c:594
 ksys_pwrite64 fs/read_write.c:701 [inline]
 __do_sys_pwrite64 fs/read_write.c:711 [inline]
 __se_sys_pwrite64 fs/read_write.c:708 [inline]
 __x64_sys_pwrite64+0x1b2/0x240 fs/read_write.c:708
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f6ed053fa07
RSP: 002b:00007f6ecdb01f20 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f6ed05d6970 RCX: 00007f6ed053fa07
RDX: 000000000000ff71 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000400 R11: 0000000000000293 R12: 0000000000000004
R13: 0000000000000004 R14: 0000000020000300 R15: 0000000000000000
task:kworker/u4:2    state:R  running task     stack:19576 pid:  148 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6287
 preempt_schedule_notrace+0x14d/0x190 kernel/sched/core.c:6538
 preempt_schedule_notrace_thunk+0x16/0x18
 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline]
 trace_lock_acquire+0xb4/0x190 include/trace/events/lock.h:13
 lock_acquire+0xa5/0x4d0 kernel/locking/lockdep.c:5596
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:267
 rcu_read_lock include/linux/rcupdate.h:687 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline]
 batadv_nc_worker+0xc8/0x5b0 net/batman-adv/network-coding.c:721
 process_one_work+0x853/0x1140 kernel/workqueue.c:2297
 worker_thread+0xac1/0x1320 kernel/workqueue.c:2444
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30
----------------
Code disassembly (best guess):
   0:	3d 8d 99 ff 85       	cmp    $0x85ff998d,%eax
   5:	c0 74 23 48 83       	shlb   $0x83,0x48(%rbx,%riz,1)
   a:	c3                   	retq
   b:	20 48 89             	and    %cl,-0x77(%rax)
   e:	d8 48 c1             	fmuls  -0x3f(%rax)
  11:	e8 03 42 80 3c       	callq  0x3c804219
  16:	38 00                	cmp    %al,(%rax)
  18:	74 08                	je     0x22
  1a:	48 89 df             	mov    %rbx,%rdi
  1d:	e8 6f 44 fb ff       	callq  0xfffb4491
  22:	48 8b 03             	mov    (%rbx),%rax
  25:	5b                   	pop    %rbx
  26:	41 5e                	pop    %r14
  28:	41 5f                	pop    %r15
* 2a:	c3                   	retq <-- trapping instruction
  2b:	e8 41 bc 26 08       	callq  0x826bc71
  30:	85 c0                	test   %eax,%eax
  32:	74 d4                	je     0x8
  34:	80 3d cf bb f4 0b 00 	cmpb   $0x0,0xbf4bbcf(%rip)        # 0xbf4bc0a
  3b:	75 cb                	jne    0x8
  3d:	c6                   	.byte 0xc6
  3e:	05                   	.byte 0x5
  3f:	c6                   	.byte 0xc6

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/10/24 20:08 upstream 6c62666d8879 282f03fb .config log report info INFO: rcu detected stall in generic_file_write_iter
ci-upstream-linux-next-kasan-gce-root 2021/12/20 16:19 linux-next 07f8c60fe60f 021b36cb .config log report info INFO: rcu detected stall in generic_file_write_iter
* Struck through repros no longer work on HEAD.