loop1: detected capacity change from 0 to 1024 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.1386/10931 is trying to acquire lock: ffff888073fe3708 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260 but task is already holding lock: ffff888023d5f0f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x91/0x900 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+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_block_allocate+0x91/0x900 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:357 hfsplus_create_cat+0x180/0x1020 fs/hfsplus/catalog.c:272 hfsplus_fill_super+0x12f6/0x1b90 fs/hfsplus/super.c:560 mount_bdev+0x287/0x3c0 fs/super.c:1400 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x24a/0xa40 fs/namespace.c:3025 do_mount fs/namespace.c:3368 [inline] __do_sys_mount fs/namespace.c:3576 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3553 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260 block_read_full_page+0x2e8/0xd10 fs/buffer.c:2290 do_read_cache_page+0x8a1/0x1030 mm/filemap.c:-1 read_mapping_page include/linux/pagemap.h:515 [inline] hfsplus_block_allocate+0xf4/0x900 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_get_block+0x40e/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 __block_write_begin fs/buffer.c:2062 [inline] block_write_begin fs/buffer.c:2122 [inline] cont_write_begin+0x58a/0x7b0 fs/buffer.c:2471 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944 __kernel_write+0x4f9/0x930 fs/read_write.c:539 __dump_emit+0x243/0x360 fs/coredump.c:943 elf_core_dump+0x27b4/0x3530 fs/binfmt_elf.c:2237 do_coredump+0x1419/0x2960 fs/coredump.c:894 get_signal+0x40a/0x12c0 kernel/signal.c:2886 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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.1.1386/10931: #0: ffff888022a2e460 (sb_writers#21){.+.+}-{0:0}, at: do_coredump+0x13fd/0x2960 fs/coredump.c:893 #1: ffff88807b67ab80 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff88807b67ab80 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: generic_file_write_iter+0x7e/0x1b0 mm/filemap.c:3941 #2: ffff88807b67a988 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455 #3: ffff888023d5f0f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x91/0x900 fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 0 PID: 10931 Comm: syz.1.1386 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260 block_read_full_page+0x2e8/0xd10 fs/buffer.c:2290 do_read_cache_page+0x8a1/0x1030 mm/filemap.c:-1 read_mapping_page include/linux/pagemap.h:515 [inline] hfsplus_block_allocate+0xf4/0x900 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_get_block+0x40e/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 __block_write_begin fs/buffer.c:2062 [inline] block_write_begin fs/buffer.c:2122 [inline] cont_write_begin+0x58a/0x7b0 fs/buffer.c:2471 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944 __kernel_write+0x4f9/0x930 fs/read_write.c:539 __dump_emit+0x243/0x360 fs/coredump.c:943 elf_core_dump+0x27b4/0x3530 fs/binfmt_elf.c:2237 do_coredump+0x1419/0x2960 fs/coredump.c:894 get_signal+0x40a/0x12c0 kernel/signal.c:2886 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f61dd4e4980 Code: 48 c1 e8 12 83 e0 01 88 15 72 5d eb 00 88 05 6f 5d eb 00 c3 50 48 8d 35 c9 24 1c 00 48 8d 3d cf 24 1c 00 31 c0 e8 20 f7 ff ff <53> 89 fb 48 83 ec 10 64 8b 04 25 94 ff ff ff 85 c0 74 2a 89 fe 31 RSP: 002b:00007f61db88aa78 EFLAGS: 00000246 ORIG_RAX: 000000000000014e RAX: 0000000000000000 RBX: 00007f61dd86afa0 RCX: 00007f61dd623c29 RDX: 00007f61db88aa80 RSI: 00007f61db88abb0 RDI: 000000000000000b RBP: 00007f61dd6a6e41 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f61dd86b038 R14: 00007f61dd86afa0 R15: 00007ffc3a4f56f8