Message-ID: <67d84052.050a0220.3657bb.0006.GAE@google.com>
Date: Mon, 17 Mar 2025 08:31:30 -0700
From: syzbot <syzbot+77e39767e330b03df7af@...kaller.appspotmail.com>
To: anna-maria@...utronix.de, frederic@...nel.org, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com, tglx@...utronix.de
Subject: [syzbot] [bcachefs?] INFO: task hung in __closure_sync_timeout (2)

Hello,

syzbot found the following issue on:

HEAD commit:    eb88e6bfbc0a Merge tag 'fsnotify_for_v6.14-rc7' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=176d83b0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=eb44f62cb82f8a0a
dashboard link: https://syzkaller.appspot.com/bug?extid=77e39767e330b03df7af
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=1583bff8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=119c7698580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-eb88e6bf.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dd1bfa9979b6/vmlinux-eb88e6bf.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5dce0ab6f758/bzImage-eb88e6bf.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/78f15ca8a908/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77e39767e330b03df7af@...kaller.appspotmail.com

INFO: task kworker/u4:6:1037 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc6-syzkaller-00212-geb88e6bfbc0a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:19128 pid:1037  tgid:1037  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: btree_node_rewrite async_btree_node_rewrite_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217
 closure_sync_timeout include/linux/closure.h:206 [inline]
 __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1728
 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:237 [inline]
 bch2_btree_update_start+0x1200/0x1540 fs/bcachefs/btree_update_interior.c:1254
 bch2_btree_node_rewrite+0x1ba/0x1230 fs/bcachefs/btree_update_interior.c:2144
 async_btree_node_rewrite_trans fs/bcachefs/btree_update_interior.c:2217 [inline]
 async_btree_node_rewrite_work+0x3fb/0xf60 fs/bcachefs/btree_update_interior.c:2253
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 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>
INFO: task syz-executor848:5323 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc6-syzkaller-00212-geb88e6bfbc0a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor848 state:D stack:17200 pid:5323  tgid:5323  ppid:5322   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217
 closure_sync_timeout include/linux/closure.h:206 [inline]
 __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1728
 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:237 [inline]
 bch2_btree_update_start+0x1200/0x1540 fs/bcachefs/btree_update_interior.c:1254
 bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1853
 bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
 __bch2_trans_commit+0x8105/0x9790 fs/bcachefs/btree_trans_commit.c:1089
 bch2_trans_commit fs/bcachefs/btree_update.h:191 [inline]
 bch2_journal_replay+0x221b/0x2b10 fs/bcachefs/recovery.c:406
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 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: 0033:0x7feb3b77fe2a
RSP: 002b:00007ffceb5721e8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffceb572200 RCX: 00007feb3b77fe2a
RDX: 0000400000000040 RSI: 0000400000000000 RDI: 00007ffceb572200
RBP: 0000400000000000 R08: 00007ffceb572240 R09: 0000000000005900
R10: 0000000000800000 R11: 0000000000000282 R12: 0000400000000040
R13: 00007ffceb572240 R14: 0000000000000003 R15: 0000000000800000
 </TASK>
INFO: task bch-reclaim/loo:5332 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc6-syzkaller-00212-geb88e6bfbc0a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:bch-reclaim/loo state:D stack:22864 pid:5332  tgid:5332  ppid:2      task_flags:0x200840 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217
 closure_sync_timeout include/linux/closure.h:206 [inline]
 __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1728
 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:237 [inline]
 bch2_btree_update_start+0x1200/0x1540 fs/bcachefs/btree_update_interior.c:1254
 bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1853
 bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908
 __bch2_trans_commit+0x8105/0x9790 fs/bcachefs/btree_trans_commit.c:1089
 bch2_trans_commit fs/bcachefs/btree_update.h:191 [inline]
 bch2_btree_write_buffer_flush_locked+0x4b12/0x5570 fs/bcachefs/btree_write_buffer.c:452
 btree_write_buffer_flush_seq+0x1c49/0x1e10 fs/bcachefs/btree_write_buffer.c:570
 bch2_btree_write_buffer_journal_flush+0xc7/0x150 fs/bcachefs/btree_write_buffer.c:586
 journal_flush_pins+0x89b/0xe40 fs/bcachefs/journal_reclaim.c:589
 __bch2_journal_reclaim+0x789/0xda0 fs/bcachefs/journal_reclaim.c:722
 bch2_journal_reclaim_thread+0x17a/0x570 fs/bcachefs/journal_reclaim.c:764
 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>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8eb393e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
4 locks held by kworker/u4:6/1037:
 #0: ffff88804085c148 ((wq_completion)btree_node_rewrite){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88804085c148 ((wq_completion)btree_node_rewrite){+.+.}-{0:0}, at: process_scheduled_works+0x98b/0x18e0 kernel/workqueue.c:3319
 #1: ffffc9000252fc60 ((work_completion)(&a->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000252fc60 ((work_completion)(&a->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9c6/0x18e0 kernel/workqueue.c:3319
 #2: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
 #2: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
 #2: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0x9a/0x1a0 fs/bcachefs/btree_iter.c:3225
 #3: ffff8880448a66d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x680/0x1540 fs/bcachefs/btree_update_interior.c:1182
2 locks held by getty/5105:
 #0: ffff8880003510a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000019b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211
3 locks held by syz-executor848/5323:
 #0: ffff888044880278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x45/0x610 fs/bcachefs/super.c:1010
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0x9a/0x1a0 fs/bcachefs/btree_iter.c:3225
 #2: ffff8880448a66d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x680/0x1540 fs/bcachefs/btree_update_interior.c:1182
4 locks held by bch-reclaim/loo/5332:
 #0: ffff8880448cb028 (&j->reclaim_lock){+.+.}-{4:4}, at: bch2_journal_reclaim_thread+0x16d/0x570 fs/bcachefs/journal_reclaim.c:763
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
 #1: ffff888044884378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e4/0xd30 fs/bcachefs/btree_iter.c:3408
 #2: ffff888044884720 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x1c3f/0x1e10 fs/bcachefs/btree_write_buffer.c:569
 #3: ffff8880448a66d0 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x680/0x1540 fs/bcachefs/btree_update_interior.c:1182

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted 6.14.0-rc6-syzkaller-00212-geb88e6bfbc0a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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>


---
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