Message-ID: <67c0c335.050a0220.222324.0271.GAE@google.com>
Date: Thu, 27 Feb 2025 11:55:33 -0800
From: syzbot <syzbot+23e4a7772eb9a9715b85@...kaller.appspotmail.com>
To: bfoster@...hat.com, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] INFO: task hung in pipe_release (6)

Hello,

syzbot found the following issue on:

HEAD commit:    d082ecbc71e9 Linux 6.14-rc4
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11fe26e4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8de9cc84d5960254
dashboard link: https://syzkaller.appspot.com/bug?extid=23e4a7772eb9a9715b85
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15fe26e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5efd609bee65/disk-d082ecbc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dfadbc41acd8/vmlinux-d082ecbc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/50189caf8ad6/bzImage-d082ecbc.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/470a5d56ad27/mount_0.gz

The issue was bisected to:

commit 1d16c605cc55ef26f0c65b362665a6c99080ccbc
Author: Kent Overstreet <kent.overstreet@...ux.dev>
Date:   Thu Nov 9 19:22:46 2023 +0000

    bcachefs: Disk space accounting rewrite

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=117c9db0580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=137c9db0580000
console output: https://syzkaller.appspot.com/x/log.txt?x=157c9db0580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+23e4a7772eb9a9715b85@...kaller.appspotmail.com
Fixes: 1d16c605cc55 ("bcachefs: Disk space accounting rewrite")

INFO: task syz-executor:5849 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20592 pid:5849  tgid:5849  ppid:5843   task_flags:0x400100 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x817/0x1010 kernel/locking/mutex.c:730
 pipe_release+0x48/0x320 fs/pipe.c:728
 __fput+0x3e9/0x9f0 fs/file_table.c:464
 __do_sys_close fs/open.c:1580 [inline]
 __se_sys_close fs/open.c:1565 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1565
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe6de58bda0
RSP: 002b:00007fff16f18de8 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000555580184ec0 RCX: 00007fe6de58bda0
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 000000000000001d
RBP: 00005555801847a0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000202 R12: 00007fff16f18e10
R13: 0000000000000023 R14: 0000555580184f0c R15: 00005555801854c8
 </TASK>
INFO: task syz.3.64:6573 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.64        state:D stack:10240 pid:6573  tgid:6572  ppid:5971   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 io_schedule+0x8d/0x110 kernel/sched/core.c:7690
 folio_wait_bit_common+0x839/0xee0 mm/filemap.c:1318
 folio_lock include/linux/pagemap.h:1163 [inline]
 invalidate_inode_pages2_range+0x48f/0x960 mm/truncate.c:639
 bch2_write_invalidate_inode_pages_range+0xce/0x120 fs/bcachefs/fs-io-pagecache.c:68
 bch2_direct_write+0x2ebf/0x3190 fs/bcachefs/fs-io-direct.c:653
 bch2_write_iter+0x19d/0x2cd0 fs/bcachefs/fs-io-buffered.c:1047
 iter_file_splice_write+0xbfa/0x1510 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x11b/0x220 fs/splice.c:1164
 splice_direct_to_actor+0x586/0xc80 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x289/0x3e0 fs/splice.c:1233
 do_sendfile+0x564/0x8a0 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f893338d169
RSP: 002b:00007f89342ae038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f89335a5fa0 RCX: 00007f893338d169
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000006
RBP: 00007f893340e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000fffa83 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f89335a5fa0 R15: 00007fffa972dc48
 </TASK>
INFO: task syz.3.64:6613 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.64        state:D stack:15824 pid:6613  tgid:6572  ppid:5971   task_flags:0x440140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 __bch2_two_state_lock+0x229/0x2c0 fs/bcachefs/two_state_shared_lock.c:7
 bch2_two_state_lock fs/bcachefs/two_state_shared_lock.h:55 [inline]
 bch2_readahead+0x9e1/0x1240 fs/bcachefs/fs-io-buffered.c:272
 read_pages+0x179/0x570 mm/readahead.c:161
 page_cache_ra_unbounded+0x708/0x820 mm/readahead.c:298
 filemap_readahead mm/filemap.c:2549 [inline]
 filemap_get_pages+0x9e4/0x1fb0 mm/filemap.c:2594
 filemap_splice_read+0x68e/0xef0 mm/filemap.c:2971
 do_splice_read fs/splice.c:985 [inline]
 splice_file_to_pipe+0x290/0x500 fs/splice.c:1295
 do_sendfile+0x508/0x8a0 fs/read_write.c:1369
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f893338d169
RSP: 002b:00007f893428d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f89335a6080 RCX: 00007f893338d169
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 00007f893340e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000002ab R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f89335a6080 R15: 00007fffa972dc48
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
2 locks held by getty/5582:
 #0: ffff88803571a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5849:
 #0: ffff88802a3d6068 (&pipe->mutex){+.+.}-{4:4}, at: pipe_release+0x48/0x320 fs/pipe.c:728
4 locks held by kworker/u8:4/6005:
 #0: ffff8880b873e7d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598
 #1: ffff8880b8728948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x41d/0x7a0 kernel/sched/psi.c:987
 #2: ffff8880b872a398 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1046 [inline]
 #2: ffff8880b872a398 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x24a/0x10e0 kernel/time/timer.c:1127
 #3: ffffffff9a832208 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x17f/0x580 lib/debugobjects.c:818
1 lock held by syz.3.64/6573:
 #0: ffff8880741e2420 (sb_writers#13){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x220 fs/splice.c:1163
2 locks held by syz.3.64/6613:
 #0: ffff88802a3d6068 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292
 #1: ffff8880744ba148 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:932 [inline]
 #1: ffff8880744ba148 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: page_cache_ra_unbounded+0x156/0x820 mm/readahead.c:229

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:399
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

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