[v6.1] possible deadlock in hfsplus_block_free

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syzbot

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Apr 16, 2023, 5:54:39 PM4/16/23
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Hello,

syzbot found the following issue on:

HEAD commit: 0102425ac76b Linux 6.1.24
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1201f2c0280000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb976cea3176ce66
dashboard link: https://syzkaller.appspot.com/bug?extid=7e5d4b6e97749bdb6731
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2bbac2ad18f4/disk-0102425a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9000ac7a5566/vmlinux-0102425a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/08367306fcea/bzImage-0102425a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7e5d4b...@syzkaller.appspotmail.com

loop2: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.1.24-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/13919 is trying to acquire lock:
ffff8880287680f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_free+0xb7/0x4d0 fs/hfsplus/bitmap.c:182

but task is already holding lock:
ffff888019411548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x2d6/0xb40 fs/hfsplus/extents.c:576

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (
&HFSPLUS_I(inode)->extents_lock
){+.+.}-{3:3}
:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
hfsplus_get_block+0x37f/0x14e0 fs/hfsplus/extents.c:260
block_read_full_folio+0x403/0xf60 fs/buffer.c:2271
filemap_read_folio+0x199/0x780 mm/filemap.c:2407
do_read_cache_folio+0x2ee/0x810 mm/filemap.c:3535
do_read_cache_page+0x32/0x220 mm/filemap.c:3577
read_mapping_page include/linux/pagemap.h:756 [inline]
hfsplus_block_allocate+0xea/0x8b0 fs/hfsplus/bitmap.c:37
hfsplus_file_extend+0xa4c/0x1b10 fs/hfsplus/extents.c:468
hfsplus_get_block+0x402/0x14e0 fs/hfsplus/extents.c:245
__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
hfsplus_write_begin+0x86/0xd0 fs/hfsplus/inode.c:52
generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3754
__generic_file_write_iter+0x176/0x400 mm/filemap.c:3882
generic_file_write_iter+0xab/0x310 mm/filemap.c:3914
call_write_iter include/linux/fs.h:2205 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x7ae/0xba0 fs/read_write.c:584
ksys_write+0x19c/0x2c0 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (
&sbi->alloc_mutex
){+.+.}-{3:3}
:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
hfsplus_block_free+0xb7/0x4d0 fs/hfsplus/bitmap.c:182
hfsplus_free_extents+0x17a/0xae0 fs/hfsplus/extents.c:363
hfsplus_file_truncate+0x7cc/0xb40 fs/hfsplus/extents.c:591
hfsplus_delete_inode+0x170/0x220
hfsplus_unlink+0x50d/0x7f0 fs/hfsplus/dir.c:405
hfsplus_rename+0xc4/0x1b0 fs/hfsplus/dir.c:547
vfs_rename+0xd8f/0x1190 fs/namei.c:4779
do_renameat2+0xb97/0x13b0 fs/namei.c:4930
__do_sys_rename fs/namei.c:4976 [inline]
__se_sys_rename fs/namei.c:4974 [inline]
__x64_sys_rename+0x82/0x90 fs/namei.c:4974
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&HFSPLUS_I(inode)->extents_lock);
lock(&sbi->alloc_mutex);
lock(&HFSPLUS_I(inode)->extents_lock);
lock(&sbi->alloc_mutex);

*** DEADLOCK ***

6 locks held by syz-executor.2/13919:
#0: ffff88808389e460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff8880194124c0 (&type->i_mutex_dir_key#8/1){+.+.}-{3:3}, at: lock_rename+0x182/0x1a0
#2: ffff888019411740 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#2: ffff888019411740 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: lock_two_nondirectories+0xde/0x130 fs/inode.c:1121
#3: ffff888019413900 (&sb->s_type->i_mutex_key#21/4){+.+.}-{3:3}, at: vfs_rename+0x825/0x1190 fs/namei.c:4749
#4: ffff888028768198 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_unlink+0x15d/0x7f0 fs/hfsplus/dir.c:370
#5: ffff888019411548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x2d6/0xb40 fs/hfsplus/extents.c:576

stack backtrace:
CPU: 0 PID: 13919 Comm: syz-executor.2 Not tainted 6.1.24-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
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:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
hfsplus_block_free+0xb7/0x4d0 fs/hfsplus/bitmap.c:182
hfsplus_free_extents+0x17a/0xae0 fs/hfsplus/extents.c:363
hfsplus_file_truncate+0x7cc/0xb40 fs/hfsplus/extents.c:591
hfsplus_delete_inode+0x170/0x220
hfsplus_unlink+0x50d/0x7f0 fs/hfsplus/dir.c:405
hfsplus_rename+0xc4/0x1b0 fs/hfsplus/dir.c:547
vfs_rename+0xd8f/0x1190 fs/namei.c:4779
do_renameat2+0xb97/0x13b0 fs/namei.c:4930
__do_sys_rename fs/namei.c:4976 [inline]
__se_sys_rename fs/namei.c:4974 [inline]
__x64_sys_rename+0x82/0x90 fs/namei.c:4974
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7f2388c169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f24551168 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f7f239abf80 RCX: 00007f7f2388c169
RDX: 0000000000000000 RSI: 0000000020000200 RDI: 00000000200001c0
RBP: 00007f7f238e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeda6d187f R14: 00007f7f24551300 R15: 0000000000022000
</TASK>
hfsplus: unable to mark blocks free: error -5
hfsplus: can't free extent


---
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syzbot

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Apr 14, 2024, 3:02:23 PM (5 days ago) Apr 14
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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