syzbot


INFO: rcu detected stall in read_iter_zero (3)

Status: auto-closed as invalid on 2022/02/06 09:28
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 389d, last: 389d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in read_iter_zero 1 859d 859d 0/24 auto-closed as invalid on 2020/10/24 11:46
upstream INFO: rcu detected stall in read_iter_zero (2) 1 526d 526d 0/24 auto-closed as invalid on 2021/09/22 21:00

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=399/1/0x4000000000000000 softirq=78464/78465 fqs=5218 
	(t=10502 jiffies g=142381 q=78407)
NMI backtrace for cpu 1
CPU: 1 PID: 8561 Comm: syz-executor.0 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x22d/0x390 kernel/rcu/tree_stall.h:343
 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]
 rcu_pending kernel/rcu/tree.c:3878 [inline]
 rcu_sched_clock_irq+0x1e33/0x2bc0 kernel/rcu/tree.c:2597
 update_process_times+0x197/0x200 kernel/time/timer.c:1785
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:__output_copy kernel/events/internal.h:178 [inline]
RIP: 0010:perf_output_read_group kernel/events/core.c:6928 [inline]
RIP: 0010:perf_output_read+0x115d/0x1480 kernel/events/core.c:6961
Code: 30 00 74 08 4c 89 e7 e8 c1 ab 29 00 49 8b 3c 24 48 8b 74 24 48 4c 89 ea e8 10 ae 29 00 48 8b 44 24 20 4c 89 f1 42 80 3c 30 00 <74> 0b 4c 89 e7 e8 99 ab 29 00 4c 89 f1 4d 01 2c 24 48 8b 44 24 18
RSP: 0018:ffffc9000602ed00 EFLAGS: 00000246
RAX: 1ffff92000c05e35 RBX: 0000000000000010 RCX: dffffc0000000000
RDX: 0000000000000010 RSI: ffffc9000602edf0 RDI: ffff8880439a6638
RBP: ffffc9000602ee90 R08: dffffc0000000000 R09: ffffed1008734cc7
R10: ffffed1008734cc7 R11: 0000000000000000 R12: ffffc9000602f1a8
R13: 0000000000000010 R14: dffffc0000000000 R15: ffffc9000602f198
 perf_output_sample+0x338/0x23e0 kernel/events/core.c:7008
 __perf_event_output kernel/events/core.c:7493 [inline]
 perf_event_output_forward+0x1e1/0x2c0 kernel/events/core.c:7507
 __perf_event_overflow+0x1f8/0x380 kernel/events/core.c:9207
 do_perf_sw_event kernel/events/core.c:9424 [inline]
 ___perf_sw_event+0x465/0x640 kernel/events/core.c:9455
 __perf_sw_event+0x13f/0x270 kernel/events/core.c:9467
 handle_mm_fault+0x21cc/0x2560 mm/memory.c:4798
 do_user_addr_fault+0x8cc/0x10c0 arch/x86/mm/fault.c:1397
 handle_page_fault arch/x86/mm/fault.c:1485 [inline]
 exc_page_fault+0xa1/0x1e0 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x1e/0x30
RIP: 0010:__clear_user arch/x86/lib/usercopy_64.c:24 [inline]
RIP: 0010:clear_user+0xe0/0x150 arch/x86/lib/usercopy_64.c:54
Code: 46 8c be 14 00 00 00 e8 4e df 7e fd 0f 01 cb 89 d8 83 e0 07 48 c1 eb 03 48 89 d9 4c 89 f7 48 85 c9 0f 84 12 00 00 00 0f 1f 00 <48> c7 07 00 00 00 00 48 83 c7 08 ff c9 75 f1 48 89 c1 85 c9 74 0a
RSP: 0018:ffffc9000602f938 EFLAGS: 00050206
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 000000000000008b
RDX: 1ffff92000c05f10 RSI: 0000000000000000 RDI: 00000000202cdfff
RBP: 00000000202ce457 R08: dffffc0000000000 R09: fffffbfff1bfa5f6
R10: fffffbfff1bfa5f6 R11: 0000000000000000 R12: 0000000000001000
R13: 00000000002cce57 R14: 00000000202cd457 R15: 00007ffffffff000
 iov_iter_zero+0x218/0x11e0 lib/iov_iter.c:947
 read_iter_zero+0x9a/0x2c0 drivers/char/mem.c:492
 do_iter_readv_writev+0x54f/0x740
 do_iter_read+0x206/0x780 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x267/0x450 fs/read_write.c:943
 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: 0033:0x7f159db1fae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f159b095188 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007f159dc32f60 RCX: 00007f159db1fae9
RDX: 000000000000000a RSI: 0000000020001900 RDI: 0000000000000007
RBP: 00007f159db79f25 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff8dc0117f R14: 00007f159b095300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess):
   0:	30 00                	xor    %al,(%rax)
   2:	74 08                	je     0xc
   4:	4c 89 e7             	mov    %r12,%rdi
   7:	e8 c1 ab 29 00       	callq  0x29abcd
   c:	49 8b 3c 24          	mov    (%r12),%rdi
  10:	48 8b 74 24 48       	mov    0x48(%rsp),%rsi
  15:	4c 89 ea             	mov    %r13,%rdx
  18:	e8 10 ae 29 00       	callq  0x29ae2d
  1d:	48 8b 44 24 20       	mov    0x20(%rsp),%rax
  22:	4c 89 f1             	mov    %r14,%rcx
  25:	42 80 3c 30 00       	cmpb   $0x0,(%rax,%r14,1)
* 2a:	74 0b                	je     0x37 <-- trapping instruction
  2c:	4c 89 e7             	mov    %r12,%rdi
  2f:	e8 99 ab 29 00       	callq  0x29abcd
  34:	4c 89 f1             	mov    %r14,%rcx
  37:	4d 01 2c 24          	add    %r13,(%r12)
  3b:	48 8b 44 24 18       	mov    0x18(%rsp),%rax

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/11/08 09:27 upstream 6b75d88fa81b 4c1be0be .config log report info INFO: rcu detected stall in read_iter_zero
* Struck through repros no longer work on HEAD.