[v6.1] possible deadlock in hfsplus_file_extend (2)

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Jan 12, 2025, 11:08:22 AM (10 days ago) Jan 12
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Hello,

syzbot found the following issue on:

HEAD commit: c63962be84ef Linux 6.1.124
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17bbdef8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b61d63ebcdeb2b69
dashboard link: https://syzkaller.appspot.com/bug?extid=f250f2829bf8deda7ffa
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/def628dfde4b/disk-c63962be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19bcf728ff3d/vmlinux-c63962be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dd43dbb11866/bzImage-c63962be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f250f2...@syzkaller.appspotmail.com

loop2: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.1.124-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.10521/7921 is trying to acquire lock:
ffff888058196648 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1d2/0x1b10 fs/hfsplus/extents.c:458

but task is already holding lock:
ffff8880550a80b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfsplus_find_init+0x146/0x1c0 fs/hfsplus/bfind.c:28

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
hfsplus_find_init+0x146/0x1c0 fs/hfsplus/bfind.c:28
hfsplus_ext_write_extent_locked fs/hfsplus/extents.c:136 [inline]
hfsplus_ext_write_extent+0x13e/0x1f0 fs/hfsplus/extents.c:150
hfsplus_write_inode+0x1e/0x5c0 fs/hfsplus/super.c:154
write_inode fs/fs-writeback.c:1460 [inline]
__writeback_single_inode+0x67d/0x11e0 fs/fs-writeback.c:1677
writeback_single_inode+0x22c/0x960 fs/fs-writeback.c:1733
sync_inode_metadata+0xc8/0x130 fs/fs-writeback.c:2789
hfsplus_file_fsync+0xf4/0x4c0 fs/hfsplus/inode.c:321
generic_write_sync include/linux/fs.h:2962 [inline]
generic_file_write_iter+0x29d/0x310 mm/filemap.c:4009
do_iter_write+0x6e6/0xc40 fs/read_write.c:861
vfs_writev fs/read_write.c:934 [inline]
do_pwritev+0x216/0x360 fs/read_write.c:1031
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 (&HFSPLUS_I(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
hfsplus_file_extend+0x1d2/0x1b10 fs/hfsplus/extents.c:458
hfsplus_bmap_reserve+0x101/0x4e0 fs/hfsplus/btree.c:358
__hfsplus_ext_write_extent+0x2a4/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x84/0xe00 fs/hfsplus/extents.c:186
hfsplus_ext_read_extent fs/hfsplus/extents.c:218 [inline]
hfsplus_file_extend+0x435/0x1b10 fs/hfsplus/extents.c:462
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:3845
__generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x857/0xbc0 fs/read_write.c:584
ksys_write+0x19c/0x2c0 fs/read_write.c:637
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(&HFSPLUS_I(inode)->extents_lock);
lock(&tree->tree_lock/1);
lock(&HFSPLUS_I(inode)->extents_lock);

*** DEADLOCK ***

5 locks held by syz.2.10521/7921:
#0: ffff88807bd5e368 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ba/0x360 fs/file.c:1031
#1: ffff8880550ae460 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x269/0xbc0 fs/read_write.c:580
#2: ffff8880581924c0 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#2: ffff8880581924c0 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: generic_file_write_iter+0x7f/0x310 mm/filemap.c:4002
#3: ffff8880581922c8 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1d2/0x1b10 fs/hfsplus/extents.c:458
#4: ffff8880550a80b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfsplus_find_init+0x146/0x1c0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 0 PID: 7921 Comm: syz.2.10521 Not tainted 6.1.124-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
hfsplus_file_extend+0x1d2/0x1b10 fs/hfsplus/extents.c:458
hfsplus_bmap_reserve+0x101/0x4e0 fs/hfsplus/btree.c:358
__hfsplus_ext_write_extent+0x2a4/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x84/0xe00 fs/hfsplus/extents.c:186
hfsplus_ext_read_extent fs/hfsplus/extents.c:218 [inline]
hfsplus_file_extend+0x435/0x1b10 fs/hfsplus/extents.c:462
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:3845
__generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x857/0xbc0 fs/read_write.c:584
ksys_write+0x19c/0x2c0 fs/read_write.c:637
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: 0033:0x7f03f3b85d29
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:00007f03f4909038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f03f3d75fa0 RCX: 00007f03f3b85d29
RDX: 000000000000fd14 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00007f03f3c01b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f03f3d75fa0 R15: 00007ffd6ecc8ab8
</TASK>


---
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