====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.608/6914 is trying to acquire lock: ffff0000fd861548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260 but task is already holding lock: ffff0000d69528f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x88/0x7e4 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+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 hfsplus_block_free+0xb8/0x47c fs/hfsplus/bitmap.c:182 hfsplus_free_extents+0x10c/0x880 fs/hfsplus/extents.c:360 hfsplus_file_truncate+0x610/0x9ac fs/hfsplus/extents.c:589 hfsplus_delete_inode+0x160/0x20c fs/hfsplus/inode.c:-1 hfsplus_unlink+0x418/0x68c fs/hfsplus/dir.c:405 vfs_unlink+0x2e0/0x4f4 fs/namei.c:4330 do_unlinkat+0x328/0x500 fs/namei.c:4398 __do_sys_unlinkat fs/namei.c:4441 [inline] __se_sys_unlinkat fs/namei.c:4434 [inline] __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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:585 -> #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 kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260 block_read_full_folio+0x2f4/0x980 fs/buffer.c:2271 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28 filemap_read_folio+0x134/0x384 mm/filemap.c:2490 do_read_cache_folio+0x24c/0x538 mm/filemap.c:3659 do_read_cache_page mm/filemap.c:3701 [inline] read_cache_page+0x6c/0x184 mm/filemap.c:3710 read_mapping_page include/linux/pagemap.h:793 [inline] hfsplus_block_allocate+0xd8/0x7e4 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0x7a0/0x13b4 fs/hfsplus/extents.c:466 hfsplus_get_block+0x324/0x11a0 fs/hfsplus/extents.c:245 __block_write_begin_int+0x350/0x1388 fs/buffer.c:1991 __block_write_begin fs/buffer.c:2041 [inline] block_write_begin fs/buffer.c:2102 [inline] cont_write_begin+0x53c/0x780 fs/buffer.c:2456 hfsplus_write_begin+0x98/0xe4 fs/hfsplus/inode.c:52 generic_perform_write+0x234/0x4f4 mm/filemap.c:3862 __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989 __kernel_write_iter+0x208/0x56c fs/read_write.c:517 __kernel_write+0xe8/0x148 fs/read_write.c:537 __dump_emit fs/coredump.c:873 [inline] dump_emit+0x224/0x324 fs/coredump.c:910 elf_core_dump+0x2120/0x2da0 fs/binfmt_elf.c:2306 do_coredump+0x10cc/0x1c68 fs/coredump.c:824 get_signal+0xdec/0x1304 kernel/signal.c:2857 do_signal arch/arm64/kernel/signal.c:1095 [inline] do_notify_resume+0x28c/0x2aa4 arch/arm64/kernel/signal.c:1148 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_ia+0xe8/0x1d0 arch/arm64/kernel/entry-common.c:534 el0t_64_sync_handler+0xd8/0xf0 arch/arm64/kernel/entry-common.c:661 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 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.1.608/6914: #0: ffff0000f2810460 (sb_writers#29){.+.+}-{0:0}, at: do_coredump+0x10a8/0x1c68 fs/coredump.c:823 #1: ffff0000fd862b80 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0000fd862b80 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: generic_file_write_iter+0x84/0x2b0 mm/filemap.c:3986 #2: ffff0000fd862988 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x18c/0x13b4 fs/hfsplus/extents.c:455 #3: ffff0000d69528f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x88/0x7e4 fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 0 PID: 6914 Comm: syz.1.608 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 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 kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260 block_read_full_folio+0x2f4/0x980 fs/buffer.c:2271 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28 filemap_read_folio+0x134/0x384 mm/filemap.c:2490 do_read_cache_folio+0x24c/0x538 mm/filemap.c:3659 do_read_cache_page mm/filemap.c:3701 [inline] read_cache_page+0x6c/0x184 mm/filemap.c:3710 read_mapping_page include/linux/pagemap.h:793 [inline] hfsplus_block_allocate+0xd8/0x7e4 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0x7a0/0x13b4 fs/hfsplus/extents.c:466 hfsplus_get_block+0x324/0x11a0 fs/hfsplus/extents.c:245 __block_write_begin_int+0x350/0x1388 fs/buffer.c:1991 __block_write_begin fs/buffer.c:2041 [inline] block_write_begin fs/buffer.c:2102 [inline] cont_write_begin+0x53c/0x780 fs/buffer.c:2456 hfsplus_write_begin+0x98/0xe4 fs/hfsplus/inode.c:52 generic_perform_write+0x234/0x4f4 mm/filemap.c:3862 __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989 __kernel_write_iter+0x208/0x56c fs/read_write.c:517 __kernel_write+0xe8/0x148 fs/read_write.c:537 __dump_emit fs/coredump.c:873 [inline] dump_emit+0x224/0x324 fs/coredump.c:910 elf_core_dump+0x2120/0x2da0 fs/binfmt_elf.c:2306 do_coredump+0x10cc/0x1c68 fs/coredump.c:824 get_signal+0xdec/0x1304 kernel/signal.c:2857 do_signal arch/arm64/kernel/signal.c:1095 [inline] do_notify_resume+0x28c/0x2aa4 arch/arm64/kernel/signal.c:1148 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_ia+0xe8/0x1d0 arch/arm64/kernel/entry-common.c:534 el0t_64_sync_handler+0xd8/0xf0 arch/arm64/kernel/entry-common.c:661 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585