syzbot

loop1: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking dependency detected
6.1.114-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.730/6401 is trying to acquire lock:
ffff8880595b1478 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xfb/0x1440 fs/hfs/extent.c:397

but task is already holding lock:
ffff88807cdf60b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x16a/0x1e0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       hfs_find_init+0x16a/0x1e0
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_get_block+0x4f0/0xb60 fs/hfs/extent.c:366
       block_read_full_folio+0x403/0xf60 fs/buffer.c:2271
       filemap_read_folio+0x199/0x780 mm/filemap.c:2489
       do_read_cache_folio+0x2ee/0x810 mm/filemap.c:3626
       do_read_cache_page+0x32/0x220 mm/filemap.c:3668
       read_mapping_page include/linux/pagemap.h:791 [inline]
       __hfs_bnode_create+0x4b5/0x7b0 fs/hfs/bnode.c:290
       hfs_bnode_find+0x240/0xf50 fs/hfs/bnode.c:335
       hfs_brec_find+0x179/0x570 fs/hfs/bfind.c:126
       hfs_brec_read+0x20/0x100 fs/hfs/bfind.c:165
       hfs_cat_find_brec+0x151/0x470 fs/hfs/catalog.c:194
       hfs_fill_super+0x10c1/0x1730 fs/hfs/super.c:419
       mount_bdev+0x2c9/0x3f0 fs/super.c:1443
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:632
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       hfs_extend_file+0xfb/0x1440 fs/hfs/extent.c:397
       hfs_bmap_reserve+0xd5/0x3f0 fs/hfs/btree.c:234
       __hfs_ext_write_extent+0x22e/0x4f0 fs/hfs/extent.c:121
       __hfs_ext_cache_extent+0x6a/0x990 fs/hfs/extent.c:174
       hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
       hfs_extend_file+0x340/0x1440 fs/hfs/extent.c:401
       hfs_get_block+0x3e0/0xb60 fs/hfs/extent.c:353
       __block_write_begin_int+0x544/0x1a30 fs/buffer.c:1991
       __block_write_begin fs/buffer.c:2041 [inline]
       block_write_begin+0x98/0x1f0 fs/buffer.c:2102
       cont_write_begin+0x63f/0x880 fs/buffer.c:2456
       hfs_write_begin+0x86/0xd0 fs/hfs/inode.c:58
       cont_expand_zero fs/buffer.c:2383 [inline]
       cont_write_begin+0x312/0x880 fs/buffer.c:2446
       hfs_write_begin+0x86/0xd0 fs/hfs/inode.c:58
       hfs_file_truncate+0x1e9/0xa10 fs/hfs/extent.c:494
       hfs_inode_setattr+0x45d/0x6a0 fs/hfs/inode.c:659
       notify_change+0xce3/0xfc0 fs/attr.c:499
       do_truncate+0x21c/0x300 fs/open.c:65
       do_sys_ftruncate+0x2e2/0x380 fs/open.c:193
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tree->tree_lock/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

4 locks held by syz.1.730/6401:
 #0: ffff888059110460 (sb_writers#26){.+.+}-{0:0}, at: do_sys_ftruncate+0x251/0x380 fs/open.c:190
 #1: ffff8880595b29a8 (&sb->s_type->i_mutex_key#31){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880595b29a8 (&sb->s_type->i_mutex_key#31){+.+.}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
 #2: ffff8880595b27f8 (&HFS_I(inode)->extents_lock#2){+.+.}-{3:3}, at: hfs_extend_file+0xfb/0x1440 fs/hfs/extent.c:397
 #3: ffff88807cdf60b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x16a/0x1e0

stack backtrace:
CPU: 1 PID: 6401 Comm: syz.1.730 Not tainted 6.1.114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
 hfs_extend_file+0xfb/0x1440 fs/hfs/extent.c:397
 hfs_bmap_reserve+0xd5/0x3f0 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x22e/0x4f0 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6a/0x990 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x340/0x1440 fs/hfs/extent.c:401
 hfs_get_block+0x3e0/0xb60 fs/hfs/extent.c:353
 __block_write_begin_int+0x544/0x1a30 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x98/0x1f0 fs/buffer.c:2102
 cont_write_begin+0x63f/0x880 fs/buffer.c:2456
 hfs_write_begin+0x86/0xd0 fs/hfs/inode.c:58
 cont_expand_zero fs/buffer.c:2383 [inline]
 cont_write_begin+0x312/0x880 fs/buffer.c:2446
 hfs_write_begin+0x86/0xd0 fs/hfs/inode.c:58
 hfs_file_truncate+0x1e9/0xa10 fs/hfs/extent.c:494
 hfs_inode_setattr+0x45d/0x6a0 fs/hfs/inode.c:659
 notify_change+0xce3/0xfc0 fs/attr.c:499
 do_truncate+0x21c/0x300 fs/open.c:65
 do_sys_ftruncate+0x2e2/0x380 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0e7b17e719
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:00007f0e7bed6038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f0e7b335f80 RCX: 00007f0e7b17e719
RDX: 0000000000000000 RSI: 0000000002000009 RDI: 0000000000000004
RBP: 00007f0e7b1f132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0e7b335f80 R15: 00007ffc6ee861d8
 </TASK>