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Message-ID: <00000000000080e10e05dd043247@google.com>
Date: Tue, 19 Apr 2022 09:16:20 -0700
From: syzbot <syzbot+306090cfa3294f0bbfb3@...kaller.appspotmail.com>
To: fweisbec@...il.com, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org, mingo@...nel.org,
syzkaller-bugs@...glegroups.com, tglx@...utronix.de,
viro@...iv.linux.org.uk
Subject: [syzbot] INFO: rcu detected stall in sys_lsetxattr
Hello,
syzbot found the following issue on:
HEAD commit: 40354149f4d7 Add linux-next specific files for 20220414
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16ae0bd0f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=a44d62051576f6f5
dashboard link: https://syzkaller.appspot.com/bug?extid=306090cfa3294f0bbfb3
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164417ccf00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=104d63d0f00000
The issue was bisected to:
commit e257039f0fc7da36ac3a522ef9a5cb4ae7852e67
Author: Al Viro <viro@...iv.linux.org.uk>
Date: Tue Mar 1 04:04:20 2022 +0000
mount_setattr(): clean the control flow and calling conventions
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14622210f00000
final oops: https://syzkaller.appspot.com/x/report.txt?x=16622210f00000
console output: https://syzkaller.appspot.com/x/log.txt?x=12622210f00000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+306090cfa3294f0bbfb3@...kaller.appspotmail.com
Fixes: e257039f0fc7 ("mount_setattr(): clean the control flow and calling conventions")
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (10499 ticks this GP) idle=23b/1/0x4000000000000000 softirq=5447/5447 fqs=5210
(t=10500 jiffies g=4401 q=63 ncpus=2)
NMI backtrace for cpu 1
CPU: 1 PID: 3614 Comm: syz-executor153 Not tainted 5.18.0-rc2-next-20220414-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+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_dump_cpu_stacks+0x262/0x3f0 kernel/rcu/tree_stall.h:369
print_cpu_stall kernel/rcu/tree_stall.h:665 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:749 [inline]
rcu_pending kernel/rcu/tree.c:4010 [inline]
rcu_sched_clock_irq.cold+0x144/0x8fc kernel/rcu/tree.c:2675
update_process_times+0x16d/0x200 kernel/time/timer.c:1811
tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243
tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
__sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103
sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:__mnt_want_write+0xdd/0x2e0 fs/namespace.c:348
Code: 00 02 00 00 89 de e8 22 64 9c ff 85 db 74 42 48 b8 00 00 00 00 00 fc ff df 4d 89 ec 49 c1 ec 03 49 01 c4 e8 e5 61 9c ff f3 90 <41> 0f b6 04 24 84 c0 74 08 3c 03 0f 8e 99 01 00 00 8b 5d 10 31 ff
RSP: 0018:ffffc90003acfdf0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000000
RDX: ffff8880209957c0 RSI: ffffffff81dda00b RDI: 0000000000000003
RBP: ffff888140174c20 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff81dda030 R11: 1ffffffff1f09899 R12: ffffed102802e986
R13: ffff888140174c30 R14: ffff888140174c50 R15: 0000000000000000
mnt_want_write+0x13d/0x3e0 fs/namespace.c:394
path_setxattr+0xb2/0x1c0 fs/xattr.c:627
__do_sys_lsetxattr fs/xattr.c:652 [inline]
__se_sys_lsetxattr fs/xattr.c:648 [inline]
__x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:648
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f7262608cc9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f72625992f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f72626904b0 RCX: 00007f7262608cc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000600
RBP: 00007f726265e074 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 695f70756f72672c R14: 695f726573752c30 R15: 00007f72626904b8
</TASK>
----------------
Code disassembly (best guess):
0: 00 02 add %al,(%rdx)
2: 00 00 add %al,(%rax)
4: 89 de mov %ebx,%esi
6: e8 22 64 9c ff callq 0xff9c642d
b: 85 db test %ebx,%ebx
d: 74 42 je 0x51
f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
16: fc ff df
19: 4d 89 ec mov %r13,%r12
1c: 49 c1 ec 03 shr $0x3,%r12
20: 49 01 c4 add %rax,%r12
23: e8 e5 61 9c ff callq 0xff9c620d
28: f3 90 pause
* 2a: 41 0f b6 04 24 movzbl (%r12),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 74 08 je 0x3b
33: 3c 03 cmp $0x3,%al
35: 0f 8e 99 01 00 00 jle 0x1d4
3b: 8b 5d 10 mov 0x10(%rbp),%ebx
3e: 31 ff xor %edi,%edi
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
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