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From: syzbot <syzbot+1fed2de07d8e11a3ec1b@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, penguin-kernel@i-love.sakura.ne.jp,
	 syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [ocfs2?] possible deadlock in ocfs2_try_remove_refcount_tree
Date: Sat, 19 Jul 2025 11:22:02 -0700	[thread overview]
Message-ID: <687be24a.a70a0220.693ce.0092.GAE@google.com> (raw)
In-Reply-To: <690ae6be-8313-46eb-a546-b895f5a7227c@I-love.SAKURA.ne.jp>

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in ocfs2_truncate_file

         option from the mount to silence this warning.
=======================================================
ocfs2: Mounting device (7,0) on (node local, slot 0) with writeback data mode.
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-syzkaller-00253-g4871b7cb27f4-dirty #0 Not tainted
------------------------------------------------------
syz.0.16/6592 is trying to acquire lock:
ffff88807a9fc618 (sb_internal#2){.+.+}-{0:0}, at: ocfs2_orphan_for_truncate fs/ocfs2/file.c:396 [inline]
ffff88807a9fc618 (sb_internal#2){.+.+}-{0:0}, at: ocfs2_truncate_file+0x648/0x1410 fs/ocfs2/file.c:500

but task is already holding lock:
ffff88807da38660 (&oi->ip_alloc_sem){++++}-{4:4}, at: ocfs2_down_write fs/ocfs2/inode.h:74 [inline]
ffff88807da38660 (&oi->ip_alloc_sem){++++}-{4:4}, at: ocfs2_truncate_file+0x36a/0x1410 fs/ocfs2/file.c:471

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&oi->ip_alloc_sem){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       ocfs2_down_write fs/ocfs2/inode.h:74 [inline]
       ocfs2_xattr_set_handle+0x3af/0x7a0 fs/ocfs2/xattr.c:3503
       ocfs2_init_security_set+0xbd/0xe0 fs/ocfs2/xattr.c:7309
       ocfs2_mknod+0x137f/0x2050 fs/ocfs2/namei.c:419
       ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:673
       lookup_open fs/namei.c:3717 [inline]
       open_last_lookups fs/namei.c:3816 [inline]
       path_openat+0x14f1/0x3830 fs/namei.c:4052
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&oi->ip_xattr_sem){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       ocfs2_down_write fs/ocfs2/inode.h:73 [inline]
       ocfs2_xattr_set_handle+0x3a0/0x7a0 fs/ocfs2/xattr.c:3503
       ocfs2_init_security_set+0xbd/0xe0 fs/ocfs2/xattr.c:7309
       ocfs2_mknod+0x137f/0x2050 fs/ocfs2/namei.c:419
       ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:673
       lookup_open fs/namei.c:3717 [inline]
       open_last_lookups fs/namei.c:3816 [inline]
       path_openat+0x14f1/0x3830 fs/namei.c:4052
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (jbd2_handle){++++}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       start_this_handle+0x1fa7/0x21c0 fs/jbd2/transaction.c:444
       jbd2__journal_start+0x2c1/0x5b0 fs/jbd2/transaction.c:501
       jbd2_journal_start+0x2a/0x40 fs/jbd2/transaction.c:540
       ocfs2_start_trans+0x376/0x6d0 fs/ocfs2/journal.c:374
       ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
       ocfs2_reserve_suballoc_bits+0x711/0x4640 fs/ocfs2/suballoc.c:834
       ocfs2_reserve_new_metadata_blocks+0x403/0x940 fs/ocfs2/suballoc.c:984
       ocfs2_mknod+0xe08/0x2050 fs/ocfs2/namei.c:347
       ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:673
       lookup_open fs/namei.c:3717 [inline]
       open_last_lookups fs/namei.c:3816 [inline]
       path_openat+0x14f1/0x3830 fs/namei.c:4052
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&journal->j_trans_barrier){.+.+}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1524
       ocfs2_start_trans+0x36a/0x6d0 fs/ocfs2/journal.c:372
       ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
       ocfs2_reserve_suballoc_bits+0x711/0x4640 fs/ocfs2/suballoc.c:834
       ocfs2_reserve_new_metadata_blocks+0x403/0x940 fs/ocfs2/suballoc.c:984
       ocfs2_mknod+0xe08/0x2050 fs/ocfs2/namei.c:347
       ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:673
       lookup_open fs/namei.c:3717 [inline]
       open_last_lookups fs/namei.c:3816 [inline]
       path_openat+0x14f1/0x3830 fs/namei.c:4052
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sb_internal#2){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
       __sb_start_write include/linux/fs.h:1795 [inline]
       sb_start_intwrite include/linux/fs.h:1978 [inline]
       ocfs2_start_trans+0x26b/0x6d0 fs/ocfs2/journal.c:370
       ocfs2_orphan_for_truncate fs/ocfs2/file.c:396 [inline]
       ocfs2_truncate_file+0x648/0x1410 fs/ocfs2/file.c:500
       ocfs2_setattr+0x1571/0x1b60 fs/ocfs2/file.c:1212
       notify_change+0xb36/0xe40 fs/attr.c:552
       do_truncate+0x1a4/0x220 fs/open.c:68
       handle_truncate fs/namei.c:3517 [inline]
       do_open fs/namei.c:3900 [inline]
       path_openat+0x306c/0x3830 fs/namei.c:4055
       do_filp_open+0x1fa/0x410 fs/namei.c:4082
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_open fs/open.c:1460 [inline]
       __se_sys_open fs/open.c:1456 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1456
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  sb_internal#2 --> &oi->ip_xattr_sem --> &oi->ip_alloc_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&oi->ip_alloc_sem);
                               lock(&oi->ip_xattr_sem);
                               lock(&oi->ip_alloc_sem);
  rlock(sb_internal#2);

 *** DEADLOCK ***

4 locks held by syz.0.16/6592:
 #0: ffff88807a9fc428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88807da389c0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:874 [inline]
 #1: ffff88807da389c0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: do_truncate+0x171/0x220 fs/open.c:63
 #2: ffff88807da386f8 (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_down_write fs/ocfs2/inode.h:73 [inline]
 #2: ffff88807da386f8 (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_truncate_file+0x359/0x1410 fs/ocfs2/file.c:471
 #3: ffff88807da38660 (&oi->ip_alloc_sem){++++}-{4:4}, at: ocfs2_down_write fs/ocfs2/inode.h:74 [inline]
 #3: ffff88807da38660 (&oi->ip_alloc_sem){++++}-{4:4}, at: ocfs2_truncate_file+0x36a/0x1410 fs/ocfs2/file.c:471

stack backtrace:
CPU: 1 UID: 0 PID: 6592 Comm: syz.0.16 Not tainted 6.16.0-rc6-syzkaller-00253-g4871b7cb27f4-dirty #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
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
 percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 __sb_start_write include/linux/fs.h:1795 [inline]
 sb_start_intwrite include/linux/fs.h:1978 [inline]
 ocfs2_start_trans+0x26b/0x6d0 fs/ocfs2/journal.c:370
 ocfs2_orphan_for_truncate fs/ocfs2/file.c:396 [inline]
 ocfs2_truncate_file+0x648/0x1410 fs/ocfs2/file.c:500
 ocfs2_setattr+0x1571/0x1b60 fs/ocfs2/file.c:1212
 notify_change+0xb36/0xe40 fs/attr.c:552
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3517 [inline]
 do_open fs/namei.c:3900 [inline]
 path_openat+0x306c/0x3830 fs/namei.c:4055
 do_filp_open+0x1fa/0x410 fs/namei.c:4082
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_open fs/open.c:1460 [inline]
 __se_sys_open fs/open.c:1456 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1456
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa61778e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa61868b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fa6179b5fa0 RCX: 00007fa61778e929
RDX: 0000000000000020 RSI: 000000000014927e RDI: 00002000000001c0
RBP: 00007fa617810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa6179b5fa0 R15: 00007fffb0c2bbe8
 </TASK>


Tested on:

commit:         4871b7cb Merge tag 'v6.16-rc6-smb3-client-fixes' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1474c38c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f09d04131ef56b22
dashboard link: https://syzkaller.appspot.com/bug?extid=1fed2de07d8e11a3ec1b
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1510c38c580000


       reply	other threads:[~2025-07-19 18:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <690ae6be-8313-46eb-a546-b895f5a7227c@I-love.SAKURA.ne.jp>
2025-07-19 18:22 ` syzbot [this message]
     [not found] <20240821210432.146003-1-djahchankoike@gmail.com>
2024-08-21 21:20 ` [syzbot] [ocfs2?] possible deadlock in ocfs2_try_remove_refcount_tree syzbot
2024-08-19  8:48 syzbot
2024-08-21  9:32 ` Edward Adam Davis
2024-08-21  9:48   ` syzbot
2024-09-23 22:04 ` syzbot
2025-06-21 14:27 ` Tetsuo Handa
2025-06-21 15:05   ` syzbot

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