loop8: detected capacity change from 0 to 1024 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.756/9725 is trying to acquire lock: ffff88802c20b048 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x39f/0x1530 fs/hfsplus/extents.c:260 but task is already holding lock: ffff888041a498f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x9d/0x8e0 fs/hfsplus/bitmap.c:35 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->alloc_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 hfsplus_block_allocate+0x9d/0x8e0 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xae4/0x1990 fs/hfsplus/extents.c:466 hfsplus_get_block+0x412/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 cont_write_begin+0x5c8/0x7e0 fs/buffer.c:2591 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 cont_expand_zero fs/buffer.c:2518 [inline] cont_write_begin+0x2ad/0x7e0 fs/buffer.c:2581 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 generic_cont_expand_simple+0x13a/0x200 fs/buffer.c:2482 hfsplus_setattr+0x169/0x280 fs/hfsplus/inode.c:263 notify_change+0xb0d/0xe10 fs/attr.c:499 do_truncate+0x19b/0x220 fs/open.c:66 vfs_truncate+0x266/0x300 fs/open.c:112 do_sys_truncate+0xe0/0x1a0 fs/open.c:135 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 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:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 hfsplus_get_block+0x39f/0x1530 fs/hfsplus/extents.c:260 block_read_full_folio+0x42e/0xf40 fs/buffer.c:2406 filemap_read_folio+0x167/0x760 mm/filemap.c:2420 do_read_cache_folio+0x470/0x7e0 mm/filemap.c:3804 do_read_cache_page+0x32/0x250 mm/filemap.c:3870 read_mapping_page include/linux/pagemap.h:892 [inline] hfsplus_block_allocate+0xff/0x8e0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xae4/0x1990 fs/hfsplus/extents.c:466 hfsplus_get_block+0x412/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 cont_write_begin+0x5c8/0x7e0 fs/buffer.c:2591 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4031 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4152 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x79a/0xc70 fs/read_write.c:860 vfs_writev fs/read_write.c:933 [inline] do_pwritev+0x205/0x340 fs/read_write.c:1030 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 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(&sbi->alloc_mutex); lock(&HFSPLUS_I(inode)->extents_lock); lock(&sbi->alloc_mutex); lock(&HFSPLUS_I(inode)->extents_lock); *** DEADLOCK *** 4 locks held by syz.8.756/9725: #0: ffff88807e284418 (sb_writers#13){.+.+}-{0:0}, at: vfs_writev fs/read_write.c:932 [inline] #0: ffff88807e284418 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1f3/0x340 fs/read_write.c:1030 #1: ffff88802c208310 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff88802c208310 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: generic_file_write_iter+0x83/0x2e0 mm/filemap.c:4149 #2: ffff88802c208108 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1fd/0x1990 fs/hfsplus/extents.c:455 #3: ffff888041a498f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x9d/0x8e0 fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 1 PID: 9725 Comm: syz.8.756 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 hfsplus_get_block+0x39f/0x1530 fs/hfsplus/extents.c:260 block_read_full_folio+0x42e/0xf40 fs/buffer.c:2406 filemap_read_folio+0x167/0x760 mm/filemap.c:2420 do_read_cache_folio+0x470/0x7e0 mm/filemap.c:3804 do_read_cache_page+0x32/0x250 mm/filemap.c:3870 read_mapping_page include/linux/pagemap.h:892 [inline] hfsplus_block_allocate+0xff/0x8e0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xae4/0x1990 fs/hfsplus/extents.c:466 hfsplus_get_block+0x412/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 cont_write_begin+0x5c8/0x7e0 fs/buffer.c:2591 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4031 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4152 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x79a/0xc70 fs/read_write.c:860 vfs_writev fs/read_write.c:933 [inline] do_pwritev+0x205/0x340 fs/read_write.c:1030 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fea1eb8f749 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:00007fea1f9ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007fea1ede5fa0 RCX: 00007fea1eb8f749 RDX: 0000000000000001 RSI: 0000200000000500 RDI: 0000000000000007 RBP: 00007fea1ec13f91 R08: 0000000000000002 R09: 0000000000000000 R10: 000000000000d8c1 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fea1ede6038 R14: 00007fea1ede5fa0 R15: 00007ffd5cdc9618