[v6.1] possible deadlock in hfs_extend_file

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6449a0ba6843 Linux 6.1.19
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14cc7cecc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=75eadb21ef1208e4
dashboard link: https://syzkaller.appspot.com/bug?extid=69a2a67f91f3cb1af824
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dc227ecd3e21/disk-6449a0ba.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1d08e21b50c2/vmlinux-6449a0ba.xz
kernel image: https://storage.googleapis.com/syzbot-assets/71a43f2c4d2c/Image-6449a0ba.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+69a2a6...@syzkaller.appspotmail.com

hfs: unable to locate alternate MDB
hfs: continuing without an alternate MDB
======================================================
WARNING: possible circular locking dependency detected
6.1.19-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/10886 is trying to acquire lock:
ffff0000d5098df8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xe4/0x1130 fs/hfs/extent.c:397

but task is already holding lock:
ffff0000dc89a0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x148/0x1c8

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{3:3}:
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
hfs_find_init+0x148/0x1c8
hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
hfs_get_block+0x29c/0x9e0 fs/hfs/extent.c:366
block_read_full_folio+0x2f4/0x98c fs/buffer.c:2271
hfs_read_folio+0x28/0x38 fs/hfs/inode.c:39
filemap_read_folio+0x14c/0x39c mm/filemap.c:2407
do_read_cache_folio+0x24c/0x544 mm/filemap.c:3535
do_read_cache_page mm/filemap.c:3577 [inline]
read_cache_page+0x6c/0x180 mm/filemap.c:3586
read_mapping_page include/linux/pagemap.h:756 [inline]
hfs_btree_open+0x440/0x1010 fs/hfs/btree.c:78
hfs_mdb_get+0x1144/0x1c2c fs/hfs/mdb.c:204
hfs_fill_super+0xd64/0x13b4 fs/hfs/super.c:406
mount_bdev+0x26c/0x368 fs/super.c:1414
hfs_mount+0x44/0x58 fs/hfs/super.c:456
legacy_get_tree+0xd4/0x16c fs/fs_context.c:610
vfs_get_tree+0x90/0x274 fs/super.c:1544
do_new_mount+0x25c/0x8c8 fs/namespace.c:3040
path_mount+0x590/0xe58 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3568
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x300/0x8e4 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
hfs_extend_file+0xe4/0x1130 fs/hfs/extent.c:397
hfs_bmap_reserve+0xd0/0x3b4 fs/hfs/btree.c:234
__hfs_ext_write_extent+0x1a0/0x468 fs/hfs/extent.c:121
__hfs_ext_cache_extent+0x84/0x754 fs/hfs/extent.c:174
hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
hfs_extend_file+0x29c/0x1130 fs/hfs/extent.c:401
hfs_get_block+0x3b8/0x9e0 fs/hfs/extent.c:353
__block_write_begin_int+0x340/0x13b4 fs/buffer.c:1991
__block_write_begin fs/buffer.c:2041 [inline]
block_write_begin fs/buffer.c:2102 [inline]
cont_write_begin+0x5c0/0x7d8 fs/buffer.c:2456
hfs_write_begin+0x98/0xe4 fs/hfs/inode.c:58
generic_perform_write+0x278/0x55c mm/filemap.c:3754
__generic_file_write_iter+0x168/0x388 mm/filemap.c:3882
generic_file_write_iter+0xb8/0x2b4 mm/filemap.c:3914
call_write_iter include/linux/fs.h:2205 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

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 ***

5 locks held by syz-executor.2/10886:
#0: ffff0000d2ff39e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xd8/0x104 fs/file.c:1046
#1: ffff00019d01e460 (sb_writers#31){.+.+}-{0:0}, at: vfs_write+0x244/0x914 fs/read_write.c:580
#2: ffff0000d509a328 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#2: ffff0000d509a328 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: generic_file_write_iter+0x88/0x2b4 mm/filemap.c:3911
#3: ffff0000d509a178 (&HFS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xe4/0x1130 fs/hfs/extent.c:397
#4: ffff0000dc89a0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x148/0x1c8

stack backtrace:
CPU: 1 PID: 10886 Comm: syz-executor.2 Not tainted 6.1.19-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x5c lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x300/0x8e4 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
hfs_extend_file+0xe4/0x1130 fs/hfs/extent.c:397
hfs_bmap_reserve+0xd0/0x3b4 fs/hfs/btree.c:234
__hfs_ext_write_extent+0x1a0/0x468 fs/hfs/extent.c:121
__hfs_ext_cache_extent+0x84/0x754 fs/hfs/extent.c:174
hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
hfs_extend_file+0x29c/0x1130 fs/hfs/extent.c:401
hfs_get_block+0x3b8/0x9e0 fs/hfs/extent.c:353
__block_write_begin_int+0x340/0x13b4 fs/buffer.c:1991
__block_write_begin fs/buffer.c:2041 [inline]
block_write_begin fs/buffer.c:2102 [inline]
cont_write_begin+0x5c0/0x7d8 fs/buffer.c:2456
hfs_write_begin+0x98/0xe4 fs/hfs/inode.c:58
generic_perform_write+0x278/0x55c mm/filemap.c:3754
__generic_file_write_iter+0x168/0x388 mm/filemap.c:3882
generic_file_write_iter+0xb8/0x2b4 mm/filemap.c:3914
call_write_iter include/linux/fs.h:2205 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.