syzbot


INFO: task hung in create_empty_buffers

Status: auto-obsoleted due to no activity on 2024/02/03 11:39
Reported-by: syzbot+768cefbff60f797b3358@syzkaller.appspotmail.com
First crash: 317d, last: 317d

Sample crash report:
INFO: task syz-executor.1:8647 blocked for more than 146 seconds.
      Not tainted 5.15.137-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:21624 pid: 8647 ppid:  3876 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6372
 instrument_atomic_write include/linux/instrumented.h:86 [inline]
 set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
 SetPagePrivate include/linux/page-flags.h:380 [inline]
 attach_page_private include/linux/pagemap.h:274 [inline]
 create_empty_buffers+0x5c0/0x6d0 fs/buffer.c:1582
 </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/3272:
 #0: ffff88814acca098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002bb32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
3 locks held by syz-executor.4/3872:
1 lock held by syz-executor.1/8647:
3 locks held by kworker/u4:27/9296:
 #0: ffff8880b9b39718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffff8880b9b27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x53d/0x810 kernel/sched/psi.c:891
 #2: ffff8880b9b28098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:946

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

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 09/06/2023
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: 8598 Comm: syz-executor.4 Not tainted 5.15.137-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:196
Code: 00 00 00 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 18 6f 63 0c 48 89 de 5b e9 57 de 48 00 cc cc cc cc cc cc cc 48 8b 04 24 <65> 48 8b 0d 64 4d 82 7e 65 8b 15 65 4d 82 7e f7 c2 00 01 ff 00 74
RSP: 0018:ffffc900052d7448 EFLAGS: 00000246
RAX: ffffffff81b1e345 RBX: 0000000000000000 RCX: ffff88807a72bb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00fff00000002015 R08: ffffffff81b1e336 R09: fffff940001844c9
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea0000c22640
R13: 000000000000000c R14: ffffea0000c22648 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f70359ee080 CR3: 000000000c68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 page_mapped+0x95/0x280 mm/util.c:767
 truncate_cleanup_page+0x1b/0x440 mm/truncate.c:172
 truncate_inode_pages_range+0x2e7/0x1290 mm/truncate.c:325
 ext4_evict_inode+0x2ae/0x1100 fs/ext4/inode.c:224
 evict+0x2a4/0x620 fs/inode.c:587
 __dentry_kill+0x436/0x650 fs/dcache.c:582
 dentry_kill+0xbb/0x290
 dput+0x1f1/0x420 fs/dcache.c:888
 __fput+0x5ec/0x890 fs/file_table.c:288
 task_work_run+0x129/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x6a3/0x2480 kernel/exit.c:872
 do_group_exit+0x144/0x310 kernel/exit.c:994
 get_signal+0xc66/0x14e0 kernel/signal.c:2889
 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
 irqentry_exit_to_user_mode+0x5/0x40 kernel/entry/common.c:314
 exc_page_fault+0x342/0x740 arch/x86/mm/fault.c:1544
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0xc9c
Code: Unable to access opcode bytes at RIP 0xc72.
RSP: 002b:00000000200003b8 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f4b2b084f80 RCX: 00007f4b2af65ae9
RDX: 0000000020000400 RSI: 00000000200003b0 RDI: 0000000022009000
RBP: 00007f4b2afb147a R08: 0000000020000480 R09: 0000000020000480
R10: 0000000020000440 R11: 0000000000000206 R12: 0000000000000000
R13: 000000000000000b R14: 00007f4b2b084f80 R15: 00007ffd4a7a2c58
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/26 11:38 linux-5.15.y 12952a23a5da 23afc60f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in create_empty_buffers
* Struck through repros no longer work on HEAD.