bisecting fixing commit since f21b807c3cf8cd7c5ca9e406b27bf1cd2f1c1238
building syzkaller on 1ba81399e2d03b53a7e631c4ab05f25af1fb1911
testing commit f21b807c3cf8cd7c5ca9e406b27bf1cd2f1c1238
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 8b21325b923fb20a897d5cf3ff1b49eb35e00ef1ffefe76ca64cf7567fdeef74
all runs: crashed: INFO: task hung in ext4_fill_super
testing current HEAD b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3
testing commit b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 5e09ae464573fbb210931db76eea697e770572847383f7ed9b4a3c295313862e
all runs: crashed: INFO: task hung in ext4_stop_mmpd
revisions tested: 2, total time: 26m29.84903925s (build: 14m6.027163434s, test: 11m41.664281571s)
the crash still happens on HEAD
commit msg: Linux 5.19-rc2
crash: INFO: task hung in ext4_stop_mmpd
INFO: task syz-executor.0:4133 blocked for more than 143 seconds.
Not tainted 5.19.0-rc2-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:27216 pid: 4133 ppid: 4113 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5116 [inline]
__schedule+0x913/0x26c0 kernel/sched/core.c:6428
schedule+0xd2/0x1f0 kernel/sched/core.c:6500
schedule_timeout+0x19d/0x250 kernel/time/timer.c:1911
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common+0x378/0x530 kernel/sched/completion.c:106
kthread_stop+0x104/0x4f0 kernel/kthread.c:708
ext4_stop_mmpd+0x34/0xb0 fs/ext4/mmp.c:255
__ext4_fill_super fs/ext4/super.c:5450 [inline]
ext4_fill_super+0x79a0/0xc190 fs/ext4/super.c:5499
get_tree_bdev+0x398/0x680 fs/super.c:1292
vfs_get_tree+0x7f/0x2c0 fs/super.c:1497
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x7e8/0x1a40 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x1f5/0x260 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x467afa
RSP: 002b:00007fe43293efa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000380 RCX: 0000000000467afa
RDX: 0000000020000000 RSI: 00000000200000c0 RDI: 00007fe43293f000
RBP: 00007fe43293f040 R08: 00007fe43293f040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 00000000200000c0 R14: 00007fe43293f000 R15: 0000000020000200
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8af7ac60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
2 locks held by getty/3317:
#0: ffff8880251d1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x1f/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900015702e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xb14/0x1040 drivers/tty/n_tty.c:2124
1 lock held by syz-executor.0/4133:
#0: ffff88807a9c80e0 (&type->s_umount_key#27/1){+.+.}-{3:3}, at: alloc_super+0x192/0x9e0 fs/super.c:228
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 5.19.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x30/0xc0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x140/0x170 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0x891/0xc20 kernel/hung_task.c:378
kthread+0x299/0x340 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 35 Comm: kworker/u4:2 Not tainted 5.19.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:rcu_rnp_online_cpus kernel/rcu/tree.c:222 [inline]
RIP: 0010:rcu_rdp_cpu_online kernel/rcu/tree.c:232 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1193 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0xc5/0x140 kernel/rcu/tree.c:1177
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 75 72 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 18 48 8d 7b 70 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 5a 48 8b 53 70 b8 01 00 00 00 48 85 d5 74 0c 65 ff 0d d4 a5 a7
RSP: 0018:ffffc90000ac78c0 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffffff8af84880 RCX: ffffffff8154cc98
RDX: 1ffffffff15f091e RSI: ffffffff8943cc60 RDI: ffffffff8af848f0
RBP: 0000000000000002 R08: 0000000000000000 R09: ffffffff8cc9b157
R10: fffffbfff199362a R11: 0000000000000001 R12: 0000000000000001
R13: 0000000000000000 R14: ffff8880101c1138 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e8a3149680 CR3: 000000000ac8e000 CR4: 0000000000350ee0
Call Trace:
rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
rcu_read_lock_held_common kernel/rcu/update.c:102 [inline]
rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x480/0x570 kernel/locking/lockdep.c:5636
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:349 [inline]
__get_locked_pte+0x105/0x210 mm/memory.c:1830
get_locked_pte include/linux/mm.h:2132 [inline]
__text_poke+0x1b3/0x8e0 arch/x86/kernel/alternative.c:1052
text_poke arch/x86/kernel/alternative.c:1137 [inline]
text_poke_bp_batch+0x44c/0x6d0 arch/x86/kernel/alternative.c:1483
text_poke_flush arch/x86/kernel/alternative.c:1589 [inline]
text_poke_flush arch/x86/kernel/alternative.c:1586 [inline]
text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1596
arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x15f/0x220 kernel/jump_label.c:177
static_key_enable+0x11/0x20 kernel/jump_label.c:190
toggle_allocation_gate mm/kfence/core.c:808 [inline]
toggle_allocation_gate+0xe3/0x310 mm/kfence/core.c:800
process_one_work+0x865/0x13d0 kernel/workqueue.c:2289
worker_thread+0x598/0xec0 kernel/workqueue.c:2436
kthread+0x299/0x340 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
----------------
Code disassembly (best guess):
0: 48 89 fa mov %rdi,%rdx
3: 48 c1 ea 03 shr $0x3,%rdx
7: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
b: 75 72 jne 0x7f
d: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
14: fc ff df
17: 48 8b 5b 18 mov 0x18(%rbx),%rbx
1b: 48 8d 7b 70 lea 0x70(%rbx),%rdi
1f: 48 89 fa mov %rdi,%rdx
22: 48 c1 ea 03 shr $0x3,%rdx
26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
* 2a: 75 5a jne 0x86 <-- trapping instruction
2c: 48 8b 53 70 mov 0x70(%rbx),%rdx
30: b8 01 00 00 00 mov $0x1,%eax
35: 48 85 d5 test %rdx,%rbp
38: 74 0c je 0x46
3a: 65 gs
3b: ff .byte 0xff
3c: 0d .byte 0xd
3d: d4 (bad)
3e: a5 movsl %ds:(%rsi),%es:(%rdi)
3f: a7 cmpsl %es:(%rdi),%ds:(%rsi)