====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.851/9576 is trying to acquire lock: ffff8880255558c8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x3a5/0x15a0 fs/hfsplus/extents.c:260 but task is already holding lock: ffff88805c9098f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x96/0x8a0 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+0x136/0xcc0 kernel/locking/mutex.c:747 hfsplus_block_allocate+0x96/0x8a0 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xafb/0x19e0 fs/hfsplus/extents.c:466 hfsplus_bmap_reserve+0x122/0x500 fs/hfsplus/btree.c:358 hfsplus_create_cat+0x1cb/0x1090 fs/hfsplus/catalog.c:272 hfsplus_fill_super+0x14bc/0x1e70 fs/hfsplus/super.c:579 mount_bdev+0x221/0x2d0 fs/super.c:1643 legacy_get_tree+0xea/0x180 fs/fs_context.c:662 vfs_get_tree+0x8c/0x280 fs/super.c:1764 do_new_mount+0x24b/0xa40 fs/namespace.c:3386 do_mount fs/namespace.c:3726 [inline] __do_sys_mount fs/namespace.c:3935 [inline] __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747 hfsplus_get_block+0x3a5/0x15a0 fs/hfsplus/extents.c:260 block_read_full_folio+0x44b/0xf60 fs/buffer.c:2406 filemap_read_folio+0x172/0x760 mm/filemap.c:2420 do_read_cache_folio+0x468/0x7d0 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+0xe0/0x8a0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xafb/0x19e0 fs/hfsplus/extents.c:466 hfsplus_get_block+0x434/0x15a0 fs/hfsplus/extents.c:245 __block_write_begin_int+0x57f/0x1af0 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 cont_write_begin+0x5ee/0x810 fs/buffer.c:2591 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4031 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4152 __kernel_write_iter+0x28c/0x690 fs/read_write.c:517 __kernel_write+0x107/0x170 fs/read_write.c:537 __dump_emit+0x20c/0x320 fs/coredump.c:882 elf_core_dump+0x2978/0x3770 fs/binfmt_elf.c:2136 do_coredump+0x17cc/0x24d0 fs/coredump.c:833 get_signal+0x1133/0x13f0 kernel/signal.c:2888 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x30 kernel/entry/common.c:315 exc_page_fault+0x8c/0x100 arch/x86/mm/fault.c:1519 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 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.2.851/9576: #0: ffff8880768ca418 (sb_writers#16){.+.+}-{0:0}, at: do_coredump+0x17ab/0x24d0 fs/coredump.c:832 #1: ffff88805ba1c690 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff88805ba1c690 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: generic_file_write_iter+0x83/0x2e0 mm/filemap.c:4149 #2: ffff88805ba1c488 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x211/0x19e0 fs/hfsplus/extents.c:455 #3: ffff88805c9098f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x96/0x8a0 fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 0 PID: 9576 Comm: syz.2.851 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747 hfsplus_get_block+0x3a5/0x15a0 fs/hfsplus/extents.c:260 block_read_full_folio+0x44b/0xf60 fs/buffer.c:2406 filemap_read_folio+0x172/0x760 mm/filemap.c:2420 do_read_cache_folio+0x468/0x7d0 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+0xe0/0x8a0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xafb/0x19e0 fs/hfsplus/extents.c:466 hfsplus_get_block+0x434/0x15a0 fs/hfsplus/extents.c:245 __block_write_begin_int+0x57f/0x1af0 fs/buffer.c:2124 __block_write_begin fs/buffer.c:2173 [inline] block_write_begin+0x9a/0x1e0 fs/buffer.c:2234 cont_write_begin+0x5ee/0x810 fs/buffer.c:2591 hfsplus_write_begin+0x8b/0xd0 fs/hfsplus/inode.c:52 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4031 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4152 __kernel_write_iter+0x28c/0x690 fs/read_write.c:517 __kernel_write+0x107/0x170 fs/read_write.c:537 __dump_emit+0x20c/0x320 fs/coredump.c:882 elf_core_dump+0x2978/0x3770 fs/binfmt_elf.c:2136 do_coredump+0x17cc/0x24d0 fs/coredump.c:833 get_signal+0x1133/0x13f0 kernel/signal.c:2888 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x30 kernel/entry/common.c:315 exc_page_fault+0x8c/0x100 arch/x86/mm/fault.c:1519 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f048259c821 Code: 00 00 00 00 0f 1f 44 00 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 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f0482816090 RCX: 00007f048259c819 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007f0482632c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f0482816128 R14: 00007f0482816090 R15: 00007ffed6576078