syzbot


INFO: task hung in anon_pipe_read

Status: auto-obsoleted due to no activity on 2025/08/14 11:31
Subsystems: bcachefs
[Documentation on labels]
First crash: 207d, last: 207d

Sample crash report:
INFO: task syz-executor:5804 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21624 pid:5804  tgid:5804  ppid:5802   task_flags:0x400100 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 __mutex_lock_common kernel/locking/mutex.c:678 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746
 anon_pipe_read+0x125/0x1040 fs/pipe.c:283
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x4d0/0x980 fs/read_write.c:570
 ksys_read+0x145/0x250 fs/read_write.c:713
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbb058d33d
RSP: 002b:00007ffdff6dbea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000055555890b760 RCX: 00007ffbb058d33d
RDX: 0000000000000400 RSI: 000055555890ba90 RDI: 0000000000000025
RBP: 00007ffdff6dc1d0 R08: 00000000313bb5e3 R09: 00005555589062d8
R10: 3fffffffffffffff R11: 0000000000000246 R12: 000055555890b878
R13: 00005555589062d0 R14: 00007ffdff6dbf50 R15: 000055555890ba30
 </TASK>
INFO: task syz.6.173:7718 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.173       state:D stack:16584 pid:7718  tgid:7717  ppid:5973   task_flags:0x440140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 __bch2_two_state_lock+0x1ea/0x370 fs/bcachefs/two_state_shared_lock.c:7
 bch2_two_state_lock fs/bcachefs/two_state_shared_lock.h:55 [inline]
 bch2_readahead+0x94f/0x1100 fs/bcachefs/fs-io-buffered.c:296
 read_pages+0x177/0x590 mm/readahead.c:160
 page_cache_ra_order+0xa24/0xc70 mm/readahead.c:515
 filemap_get_pages+0x43c/0x1eb0 mm/filemap.c:2591
 filemap_splice_read+0x4fc/0xbc0 mm/filemap.c:2981
 do_splice_read fs/splice.c:979 [inline]
 splice_file_to_pipe+0x270/0x440 fs/splice.c:1289
 do_sendfile+0x475/0x7d0 fs/read_write.c:1374
 __do_sys_sendfile64 fs/read_write.c:1423 [inline]
 __se_sys_sendfile64+0xd9/0x190 fs/read_write.c:1415
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f390638e969
RSP: 002b:00007f3907186038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f39065b5fa0 RCX: 00007f390638e969
RDX: 0000200000000080 RSI: 0000000000000006 RDI: 0000000000000000
RBP: 00007f3906410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000fff R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f39065b5fa0 R15: 00007ffcc97755c8
 </TASK>
INFO: task syz.6.173:7765 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.173       state:D stack:19232 pid:7765  tgid:7717  ppid:5973   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 io_schedule+0x81/0xe0 kernel/sched/core.c:7742
 folio_wait_bit_common+0x6b0/0xb90 mm/filemap.c:1317
 folio_lock include/linux/pagemap.h:1137 [inline]
 invalidate_inode_pages2_range+0x557/0xa80 mm/truncate.c:686
 bch2_write_invalidate_inode_pages_range+0xc5/0x110 fs/bcachefs/fs-io-pagecache.c:68
 bch2_direct_write+0x2abc/0x2d50 fs/bcachefs/fs-io-direct.c:661
 bch2_write_iter+0x18f/0x2b90 fs/bcachefs/fs-io-buffered.c:1072
 iter_file_splice_write+0x937/0x1000 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0xfe/0x160 fs/splice.c:1158
 splice_direct_to_actor+0x5a8/0xcc0 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0x181/0x270 fs/splice.c:1227
 do_sendfile+0x4da/0x7d0 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1415
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f390638e969
RSP: 002b:00007f3907165038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f39065b6080 RCX: 00007f390638e969
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000005
RBP: 00007f3906410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f39065b6080 R15: 00007ffcc97755c8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/u8:6/4232:
 #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
 #1: ffff8880b8823b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x318/0x6d0 kernel/sched/psi.c:975
 #2: ffffffff999c7338 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873
1 lock held by klogd/5176:
 #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
2 locks held by getty/5576:
 #0: ffff88803053e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5804:
 #0: ffff888031b0c468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_read+0x125/0x1040 fs/pipe.c:283
2 locks held by syz.6.173/7718:
 #0: ffff888031b0c468 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x440 fs/splice.c:1286
 #1: ffff8880577419b0 (mapping.invalidate_lock#4){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:922 [inline]
 #1: ffff8880577419b0 (mapping.invalidate_lock#4){.+.+}-{4:4}, at: page_cache_ra_order+0x445/0xc70 mm/readahead.c:491
1 lock held by syz.6.173/7765:
 #0: ffff88802d04a420 (sb_writers#13){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x160 fs/splice.c:1157

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: 43 d4 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d a3 bf 18 00 f3 0f 1e fa fb f4 <e9> 18 d4 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: ad34c72aa9ea2600 RBX: ffffffff81977048 RCX: ad34c72aa9ea2600
RDX: 0000000000000001 RSI: ffffffff8d738ea1 RDI: ffffffff8bc10660
RBP: ffffffff8dc07ec0 R08: ffff8880b8832b5b R09: 1ffff1101710656b
R10: dffffc0000000000 R11: ffffed101710656c R12: ffffffff8f7dd370
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a48
FS:  0000000000000000(0000) GS:ffff8881260f9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b3bde1c168 CR3: 000000000dd38000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:743
 start_kernel+0x470/0x4f0 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/16 11:27 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in anon_pipe_read
2025/05/16 11:24 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in anon_pipe_read
2025/05/16 11:20 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in anon_pipe_read
2025/05/16 11:17 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in anon_pipe_read
2025/05/16 11:13 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in anon_pipe_read
* Struck through repros no longer work on HEAD.