syzbot


INFO: task hung in get_super

Status: auto-obsoleted due to no activity on 2024/02/08 07:44
Reported-by: syzbot+7b1835d96ffa5d7a06b5@syzkaller.appspotmail.com
First crash: 200d, last: 200d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in get_super (2) reiserfs 1 255d 255d 0/26 auto-obsoleted due to no activity on 2023/12/05 22:55
android-49 INFO: task hung in get_super 4 2161d 2189d 0/3 auto-closed as invalid on 2019/02/22 14:56
upstream INFO: task hung in get_super fs arm 6 454d 638d 0/26 auto-obsoleted due to no activity on 2023/05/20 18:34

Sample crash report:
INFO: task syz-executor.5:2281 blocked for more than 143 seconds.
      Not tainted 5.15.137-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:27520 pid: 2281 ppid: 29417 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6372
 schedule+0x11b/0x1f0 kernel/sched/core.c:6455
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6514
 rwsem_down_read_slowpath+0x605/0xb40 kernel/locking/rwsem.c:1047
 __down_read_common kernel/locking/rwsem.c:1231 [inline]
 __down_read kernel/locking/rwsem.c:1244 [inline]
 down_read+0x9a/0x2e0 kernel/locking/rwsem.c:1490
 get_super+0xfe/0x1f0 fs/super.c:776
 fsync_bdev+0x14/0xb0 block/bdev.c:214
 blkdev_flushbuf block/ioctl.c:352 [inline]
 blkdev_common_ioctl+0xd0f/0x2080 block/ioctl.c:477
 blkdev_ioctl+0x286/0x6b0 block/ioctl.c:597
 block_ioctl+0xb1/0xf0 block/fops.c:493
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f2aadd73ae9
RSP: 002b:00007f2aac2f50c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2aade92f80 RCX: 00007f2aadd73ae9
RDX: ffffffffffffffff RSI: 0000000000001261 RDI: 0000000000000003
RBP: 00007f2aaddbf47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2aade92f80 R15: 00007fff217a71b8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91f020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3266:
 #0: ffff8880244b4098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900022a32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:9/7425:
 #0: ffff8880b9a39718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffff8880b9a27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x53d/0x810 kernel/sched/psi.c:891
1 lock held by syz-executor.0/31939:
1 lock held by syz-executor.5/2281:
 #0: ffff888016ef00e0 (&type->s_umount_key#70){++++}-{3:3}, at: get_super+0xfe/0x1f0 fs/super.c:776
1 lock held by syz-executor.4/6025:
 #0: ffff888016ef00e0 (&type->s_umount_key#70){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:703

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.137-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 31939 Comm: syz-executor.0 Not tainted 5.15.137-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:_compound_head include/linux/page-flags.h:198 [inline]
RIP: 0010:PageReferenced include/linux/page-flags.h:345 [inline]
RIP: 0010:mark_page_accessed+0x8e/0x1330 mm/swap.c:406
Code: 08 4c 89 f0 48 c1 e8 03 48 89 04 24 42 80 3c 28 00 74 08 4c 89 f7 e8 51 e4 1d 00 49 8b 1e 89 de 83 e6 01 31 ff e8 b2 32 d4 ff <f6> c3 01 0f 85 36 0e 00 00 e8 c4 2e d4 ff 4c 89 fb 48 89 d8 48 c1
RSP: 0018:ffffc900030ef5e8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffea00027fb008 RCX: ffff88807e7f9dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffea00027fae88 R08: ffffffff81abf37e R09: fffffbfff1bc71e6
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88808befb2b8
R13: dffffc0000000000 R14: ffffea00027fae88 R15: ffffea00027fae80
FS:  00007fe2756966c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00f674481 CR3: 0000000098684000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __find_get_block+0x2d7/0x1350 fs/buffer.c:1314
 __getblk_gfp+0x2d/0xaf0 fs/buffer.c:1332
 __bread_gfp+0x2a/0x390 fs/buffer.c:1381
 sb_bread include/linux/buffer_head.h:337 [inline]
 exfat_get_dentry+0x678/0x970 fs/exfat/dir.c:737
 exfat_create_upcase_table+0x258/0xfa0 fs/exfat/nls.c:764
 __exfat_fill_super fs/exfat/super.c:588 [inline]
 exfat_fill_super+0x1249/0x2d70 fs/exfat/super.c:644
 get_tree_bdev+0x3fe/0x620 fs/super.c:1312
 vfs_get_tree+0x88/0x270 fs/super.c:1517
 do_new_mount+0x28b/0xae0 fs/namespace.c:2994
 do_mount fs/namespace.c:3337 [inline]
 __do_sys_mount fs/namespace.c:3545 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3522
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe2771371ea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe275695ee8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe275695f80 RCX: 00007fe2771371ea
RDX: 0000000020001500 RSI: 0000000020000140 RDI: 00007fe275695f40
RBP: 0000000020001500 R08: 00007fe275695f80 R09: 0000000000000800
R10: 0000000000000800 R11: 0000000000000206 R12: 0000000020000140
R13: 00007fe275695f40 R14: 00000000000014fe R15: 0000000020004800
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/31 07:43 linux-5.15.y 12952a23a5da b5729d82 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in get_super
* Struck through repros no longer work on HEAD.