syzbot


INFO: task can't die in d_alloc_parallel

Status: fixed on 2021/05/31 09:57
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+161fa46cef42e0f81251@syzkaller.appspotmail.com
Fix commit: 0ce20dd84089 mm: add Kernel Electric-Fence infrastructure
First crash: 1287d, last: 1267d

Sample crash report:
INFO: task syz-executor.0:26599 can't die for more than 143 seconds.
task:syz-executor.0  state:D stack:27160 pid:26599 ppid:  8503 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4313 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5064
 schedule+0xcf/0x270 kernel/sched/core.c:5143
 d_wait_lookup fs/dcache.c:2534 [inline]
 d_alloc_parallel+0x118a/0x19b0 fs/dcache.c:2616
 lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3033
 open_last_lookups fs/namei.c:3180 [inline]
 path_openat+0x96d/0x2730 fs/namei.c:3368
 do_filp_open+0x17e/0x3c0 fs/namei.c:3398
 do_sys_openat2+0x16d/0x420 fs/open.c:1172
 do_sys_open fs/open.c:1188 [inline]
 __do_sys_open fs/open.c:1196 [inline]
 __se_sys_open fs/open.c:1192 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1192
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
RSP: 002b:00007f0664991c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020008f40
RBP: 000000000119c068 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c034
R13: 00007fff9428262f R14: 00007f06649929c0 R15: 000000000119c034
INFO: task syz-executor.0:26599 blocked for more than 143 seconds.
      Not tainted 5.11.0-rc1-next-20210104-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:27160 pid:26599 ppid:  8503 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4313 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5064
 schedule+0xcf/0x270 kernel/sched/core.c:5143
 d_wait_lookup fs/dcache.c:2534 [inline]
 d_alloc_parallel+0x118a/0x19b0 fs/dcache.c:2616
 lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3033
 open_last_lookups fs/namei.c:3180 [inline]
 path_openat+0x96d/0x2730 fs/namei.c:3368
 do_filp_open+0x17e/0x3c0 fs/namei.c:3398
 do_sys_openat2+0x16d/0x420 fs/open.c:1172
 do_sys_open fs/open.c:1188 [inline]
 __do_sys_open fs/open.c:1196 [inline]
 __se_sys_open fs/open.c:1192 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1192
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
RSP: 002b:00007f0664991c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020008f40
RBP: 000000000119c068 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c034
R13: 00007fff9428262f R14: 00007f06649929c0 R15: 000000000119c034
INFO: task syz-executor.0:26615 can't die for more than 144 seconds.
task:syz-executor.0  state:R  running task     stack:27472 pid:26615 ppid:  8503 flags:0x00004006
Call Trace:

Showing all locks held in the system:
1 lock held by khungtaskd/1649:
 #0: ffffffff8b363c60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254
1 lock held by in:imklog/8191:
 #0: ffff88801377caf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947
1 lock held by syz-executor.0/26599:
 #0: ffff888031040150 (&type->i_mutex_dir_key#8){.+.+}-{3:3}, at: inode_lock_shared include/linux/fs.h:783 [inline]
 #0: ffff888031040150 (&type->i_mutex_dir_key#8){.+.+}-{3:3}, at: open_last_lookups fs/namei.c:3179 [inline]
 #0: ffff888031040150 (&type->i_mutex_dir_key#8){.+.+}-{3:3}, at: path_openat+0x14a3/0x2730 fs/namei.c:3368
4 locks held by syz-executor.0/26615:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1649 Comm: khungtaskd Not tainted 5.11.0-rc1-next-20210104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline]
 watchdog+0xd89/0xf30 kernel/hung_task.c:338
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 55 Comm: kworker/u4:2 Not tainted 5.11.0-rc1-next-20210104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:lock_release+0x3d5/0x710 kernel/locking/lockdep.c:5445
Code: 15 02 00 00 48 c7 c7 60 a2 4b 89 e8 05 4c 94 07 b8 ff ff ff ff 65 0f c1 05 98 6c a9 7e 83 f8 01 0f 85 67 01 00 00 ff 34 24 9d <48> b8 00 00 00 00 00 fc ff df 48 01 c5 48 c7 45 00 00 00 00 00 c7
RSP: 0018:ffffc90000f4fbc8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 9affe5dc7ae6db0f RCX: ffffc90000f4fc18
RDX: 1ffff1100220fbb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff920001e9f7b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000003 R14: ffff88801107dd88 R15: ffff88801107d400
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc93dd8b000 CR3: 0000000025a0d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 rcu_lock_release include/linux/rcupdate.h:264 [inline]
 rcu_read_unlock include/linux/rcupdate.h:702 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x7a3/0xe50 net/batman-adv/network-coding.c:715
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/01/04 18:32 linux-next 766eff5a4f6c 79264ae3 .config console log report info ci-upstream-linux-next-kasan-gce-root
2020/12/15 16:53 linux-next 9317f948b0b1 97183ed7 .config console log report info ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.