[syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    1868f9d0260e Merge tag 'for-linux-6.12-ofs1' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12f6ff00580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d29c10b70cc6fdb8
dashboard link: https://syzkaller.appspot.com/bug?extid=820dc3b465c69f766a57
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/26c691e641b7/disk-1868f9d0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dfe97fd5f2eb/vmlinux-1868f9d0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4a385cd95bd6/bzImage-1868f9d0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+820dc3b465c69f766a57@syzkaller.appspotmail.com

INFO: task bch-reclaim/loo:6887 blocked for more than 143 seconds.
      Not tainted 6.11.0-syzkaller-07462-g1868f9d0260e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:bch-reclaim/loo state:D stack:25080 pid:6887  tgid:6887  ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5264 [inline]
 __schedule+0x1843/0x4b00 kernel/sched/core.c:6607
 __schedule_loop kernel/sched/core.c:6684 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6699
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6756
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:738
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:0/11:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000107d00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000107d00 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
3 locks held by kworker/u8:1/12:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276
1 lock held by khungtaskd/30:
 #0: ffffffff8e9389e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e9389e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e9389e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6701
3 locks held by kworker/u8:4/66:
 #0: ffff88802dfb1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88802dfb1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc900020bfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc900020bfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4196
5 locks held by kworker/u8:8/2941:
 #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90009b17d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90009b17d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcaa8d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
 #3: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe9/0xaa0 net/core/dev.c:11930
 #4: ffffffff8e93df78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
 #4: ffffffff8e93df78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976
2 locks held by dhcpcd/4884:
 #0: ffff88806f6926c8 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0x119/0x790 net/netlink/af_netlink.c:2404
 #1: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #1: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_dumpit+0x99/0x200 net/core/rtnetlink.c:6505
2 locks held by getty/4974:
 #0: ffff88814bd6a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031232f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by kworker/u8:10/6132:
5 locks held by syz-executor/6609:
1 lock held by bch-reclaim/loo/6887:
 #0: ffff88806664af28 (&j->reclaim_lock){+.+.}-{3:3}, at: bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:738
1 lock held by syz.2.199/7144:
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120
1 lock held by syz.4.224/7389:
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: super_lock+0x196/0x400 fs/super.c:120
1 lock held by syz.2.252/7644:
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88802425c0e0 (&type->s_umount_key#108){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120
1 lock held by syz-executor/7707:
1 lock held by syz-executor/8018:
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/8169:
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/8186:
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcb73c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-syzkaller-07462-g1868f9d0260e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 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:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 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
CPU: 1 UID: 0 PID: 7707 Comm: syz-executor Not tainted 6.11.0-syzkaller-07462-g1868f9d0260e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4823 [inline]
RIP: 0010:__lock_acquire+0x4dc/0x2050 kernel/locking/lockdep.c:5149
Code: 13 00 00 44 89 3b 44 89 c3 48 89 d8 48 c1 e8 06 48 8d 3c c5 80 97 21 94 be 08 00 00 00 e8 ec f3 88 00 48 0f a3 1d a4 62 b1 12 <73> 27 48 69 c3 c8 00 00 00 48 8d 98 80 16 be 93 48 ba 00 00 00 00
RSP: 0018:ffffc900033cf510 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000022 RCX: ffffffff817034d4
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff94219780
RBP: 0000000000000000 R08: ffffffff94219787 R09: 1ffffffff28432f0
R10: dffffc0000000000 R11: fffffbfff28432f1 R12: ffff88802e8c5a00
R13: 0000000000000022 R14: 0000000000020022 R15: 0000000000000000
FS:  0000555586251500(0000) GS:ffff8880b8900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f26c7f08178 CR3: 000000004783c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 __d_lookup+0x81/0x7b0 fs/dcache.c:2321
 lookup_fast+0x74/0x4a0 fs/namei.c:1690
 walk_component fs/namei.c:2049 [inline]
 link_path_walk+0x672/0xea0 fs/namei.c:2418
 path_openat+0x266/0x3590 fs/namei.c:3929
 do_filp_open+0x235/0x490 fs/namei.c:3960
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1441
 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: 0033:0x7f8b6f37c890
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 19 8f 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 6c 8f 02 00 8b 44
RSP: 002b:00007fff27a11b50 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8b6f37c890
RDX: 0000000000000000 RSI: 00007fff27a11c80 RDI: 00000000ffffff9c
RBP: 00007fff27a11c80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007fff27a12d00
R13: 00007f8b6f3f0a14 R14: 00005555862514a8 R15: 0000000000000005
 </TASK>


---
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#syz undup

Re: [syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    ad46e8f95e93 Merge tag 'pm-6.12-rc1-2' of git://git.kernel..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17257e27980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4123da9de65c5cb5
dashboard link: https://syzkaller.appspot.com/bug?extid=820dc3b465c69f766a57
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=149c5e80580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=149f8d9f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0a6feee5a983/disk-ad46e8f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0017287e7d32/vmlinux-ad46e8f9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0ed0fe56738c/bzImage-ad46e8f9.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/984eda72cdcf/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+820dc3b465c69f766a57@syzkaller.appspotmail.com

INFO: task bch-reclaim/loo:5227 blocked for more than 143 seconds.
      Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:bch-reclaim/loo state:D stack:26552 pid:5227  tgid:5227  ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:739
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 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/30:
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6701
2 locks held by getty/4974:
 #0: ffff88814bd950a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
5 locks held by syz-executor104/5217:
1 lock held by bch-reclaim/loo/5227:
 #0: ffff8880773cb0a8 (&j->reclaim_lock){+.+.}-{3:3}, at: bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:739

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 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
CPU: 1 UID: 0 PID: 5217 Comm: syz-executor104 Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:__trans_next_path fs/bcachefs/btree_iter.h:109 [inline]
RIP: 0010:__bch2_trans_unlock fs/bcachefs/btree_locking.c:726 [inline]
RIP: 0010:bch2_trans_unlock+0x41/0x470 fs/bcachefs/btree_locking.c:810
Code: 00 00 00 00 00 fc ff df e8 bc 97 7a fd 49 8d 5f 3a 48 89 dd 48 c1 ed 03 42 0f b6 44 35 00 84 c0 0f 85 bb 03 00 00 44 0f b7 23 <bf> 01 00 00 00 44 89 e6 e8 32 9b 7a fd 41 83 fc 01 0f 86 90 02 00
RSP: 0018:ffffc90002f5f338 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88807e07003a RCX: ffff8880772f5a00
RDX: 0000000000000000 RSI: 0000000000000009 RDI: ffff88807e070000
RBP: 1ffff1100fc0e007 R08: ffffffff842029da R09: 1ffff920005ebe64
R10: dffffc0000000000 R11: fffff520005ebe65 R12: 0000000000000040
R13: ffffc90002f5f550 R14: dffffc0000000000 R15: ffff88807e070000
FS:  0000555563498380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd670dbd0c CR3: 0000000029568000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 btree_write_buffer_flush_seq+0x17a/0x1bc0 fs/bcachefs/btree_write_buffer.c:501
 bch2_btree_write_buffer_journal_flush+0x4e/0x80 fs/bcachefs/btree_write_buffer.c:525
 journal_flush_pins+0x5f7/0xb20 fs/bcachefs/journal_reclaim.c:565
 journal_flush_done+0x8e/0x260 fs/bcachefs/journal_reclaim.c:819
 bch2_journal_flush_pins+0x102/0x3a0 fs/bcachefs/journal_reclaim.c:852
 bch2_journal_flush_all_pins fs/bcachefs/journal_reclaim.h:76 [inline]
 __bch2_fs_read_only+0x124/0x430 fs/bcachefs/super.c:274
 bch2_fs_read_only+0xb57/0x1200 fs/bcachefs/super.c:354
 __bch2_fs_stop+0x105/0x540 fs/bcachefs/super.c:619
 generic_shutdown_super+0x139/0x2d0 fs/super.c:642
 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2179
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:228
 ptrace_notify+0x2d2/0x380 kernel/signal.c:2403
 ptrace_report_syscall include/linux/ptrace.h:415 [inline]
 ptrace_report_syscall_exit include/linux/ptrace.h:477 [inline]
 syscall_exit_work+0xc6/0x190 kernel/entry/common.c:173
 syscall_exit_to_user_mode_prepare kernel/entry/common.c:200 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:205 [inline]
 syscall_exit_to_user_mode+0x279/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d6ff06587
Code: 07 00 48 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeb085b6c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000555563498338 RCX: 00007f7d6ff06587
RDX: 00000000000108d0 RSI: 0000000000000009 RDI: 00007ffeb085c870
RBP: 0000000000000064 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000246 R12: 00007ffeb085c870
R13: 00005555634a1700 R14: 431bde82d7b634db R15: 00007ffeb085d900
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.552 msecs


---
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.

Re: [syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[syzbot]

syzbot has bisected this issue to:

commit b1d63b06e8398eb048dcc455acc628e6655d7499
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date:   Fri Jun 28 22:10:47 2024 +0000

    bcachefs: Make read_only a mount option again, but hidden

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10c6de80580000
start commit:   ad46e8f95e93 Merge tag 'pm-6.12-rc1-2' of git://git.kernel..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12c6de80580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14c6de80580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4123da9de65c5cb5
dashboard link: https://syzkaller.appspot.com/bug?extid=820dc3b465c69f766a57
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=149c5e80580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=149f8d9f980000

Reported-by: syzbot+820dc3b465c69f766a57@syzkaller.appspotmail.com
Fixes: b1d63b06e839 ("bcachefs: Make read_only a mount option again, but hidden")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[Edward Adam Davis]

avoid race conditions when journal's reclaim and flush acquire reclaim_lock

#syz test

diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c
index ace291f175dd..58a745c72aac 100644
--- a/fs/bcachefs/journal_reclaim.c
+++ b/fs/bcachefs/journal_reclaim.c
@@ -731,7 +731,7 @@ static int bch2_journal_reclaim_thread(void *arg)
 
 	j->last_flushed = jiffies;
 
-	while (!ret && !kthread_should_stop()) {
+	while (!j->flush_in_progress && !ret && !kthread_should_stop()) {
 		bool kicked = j->reclaim_kicked;
 
 		j->reclaim_kicked = false;

Re: [syzbot] [bcachefs?] INFO: task hung in bch2_journal_reclaim_thread (2)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in bch2_fs_btree_cache_exit

bcachefs (loop0): flushing journal and stopping allocators complete, journal seq 10
bcachefs (loop0): unshutdown complete, journal seq 11
bcachefs (loop0): done going read-only, filesystem not clean
bcachefs (loop0): shutdown complete
------------[ cut here ]------------
kernel BUG at fs/bcachefs/btree_cache.c:594!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 5815 Comm: syz-executor Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:bch2_fs_btree_cache_exit+0x1124/0x1130 fs/bcachefs/btree_cache.c:593
Code: fd 90 0f 0b e8 6d 46 84 fd 90 0f 0b e8 65 46 84 fd 90 0f 0b e8 5d 46 84 fd 90 0f 0b e8 55 46 84 fd 90 0f 0b e8 4d 46 84 fd 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003717c40 EFLAGS: 00010293
RAX: ffffffff8410a3d3 RBX: 0000000000000002 RCX: ffff88802d6a9e00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 1ffff11006350f16 R08: ffffffff84109a77 R09: 1ffff1100c0e03b6
R10: dffffc0000000000 R11: ffffed100c0e03b7 R12: ffff888060701c78
R13: ffff888060700000 R14: 0000000000000000 R15: dffffc0000000000
FS:  000055555b937500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3b2944000 CR3: 000000002888e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __bch2_fs_free fs/bcachefs/super.c:556 [inline]
 bch2_fs_release+0x20e/0x7d0 fs/bcachefs/super.c:610
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22f/0x480 lib/kobject.c:737
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe3bbb7f327
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd2b5b2c48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe3bbb7f327
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd2b5b2d00
RBP: 00007ffd2b5b2d00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd2b5b3d80
R13: 00007fe3bbbf0134 R14: 0000000000045d95 R15: 00007ffd2b5b3dc0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_fs_btree_cache_exit+0x1124/0x1130 fs/bcachefs/btree_cache.c:593
Code: fd 90 0f 0b e8 6d 46 84 fd 90 0f 0b e8 65 46 84 fd 90 0f 0b e8 5d 46 84 fd 90 0f 0b e8 55 46 84 fd 90 0f 0b e8 4d 46 84 fd 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003717c40 EFLAGS: 00010293
RAX: ffffffff8410a3d3 RBX: 0000000000000002 RCX: ffff88802d6a9e00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 1ffff11006350f16 R08: ffffffff84109a77 R09: 1ffff1100c0e03b6
R10: dffffc0000000000 R11: ffffed100c0e03b7 R12: ffff888060701c78
R13: ffff888060700000 R14: 0000000000000000 R15: dffffc0000000000
FS:  000055555b937500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c000d98000 CR3: 000000002888e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit:         850925a8 Merge tag '9p-for-6.12-rc5' of https://github..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=161704a7980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=41330fd2db03893d
dashboard link: https://syzkaller.appspot.com/bug?extid=820dc3b465c69f766a57
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=113eaebb980000