====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.6.2170/18014 is trying to acquire lock: ffff8880203b1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x39e/0x1670 fs/hfsplus/extents.c:260 but task is already holding lock: ffff8880286918f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xa7/0xce0 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){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 hfsplus_block_allocate+0xa7/0xce0 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xb2d/0x1d70 fs/hfsplus/extents.c:464 hfsplus_bmap_reserve+0x125/0x510 fs/hfsplus/btree.c:358 hfsplus_create_cat+0x1e2/0x11b0 fs/hfsplus/catalog.c:272 hfsplus_fill_super+0x1247/0x19e0 fs/hfsplus/super.c:601 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1691 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x329/0xa50 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 hfsplus_get_block+0x39e/0x1670 fs/hfsplus/extents.c:260 block_read_full_folio+0x29f/0x830 fs/buffer.c:2420 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2496 do_read_cache_folio+0x358/0x590 mm/filemap.c:4096 do_read_cache_page mm/filemap.c:4162 [inline] read_cache_page+0x5d/0x170 mm/filemap.c:4171 read_mapping_page include/linux/pagemap.h:1022 [inline] hfsplus_block_allocate+0xf3/0xce0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xb2d/0x1d70 fs/hfsplus/extents.c:464 hfsplus_get_block+0x42c/0x1670 fs/hfsplus/extents.c:245 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x737/0xae0 fs/buffer.c:2594 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314 generic_file_write_iter+0x14a/0x680 mm/filemap.c:4457 __kernel_write_iter+0x41e/0x880 fs/read_write.c:619 __kernel_write+0x106/0x170 fs/read_write.c:639 __dump_emit+0x20b/0x320 fs/coredump.c:1220 elf_core_dump+0x2bef/0x3ad0 fs/binfmt_elf.c:2063 coredump_write+0x11de/0x1980 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x369e/0x4270 fs/coredump.c:1200 get_signal+0x1107/0x1330 kernel/signal.c:3019 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x176/0x620 kernel/entry/common.c:196 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 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.6.2170/18014: #0: ffff88803756a420 (sb_writers#24){.+.+}-{0:0}, at: do_coredump fs/coredump.c:1126 [inline] #0: ffff88803756a420 (sb_writers#24){.+.+}-{0:0}, at: vfs_coredump+0x369e/0x4270 fs/coredump.c:1200 #1: ffff8880203b2b78 (&sb->s_type->i_mutex_key#40){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff8880203b2b78 (&sb->s_type->i_mutex_key#40){+.+.}-{4:4}, at: generic_file_write_iter+0x11e/0x680 mm/filemap.c:4454 #2: ffff8880203b2988 (&hip->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x215/0x1d70 fs/hfsplus/extents.c:453 #3: ffff8880286918f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xa7/0xce0 fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 1 UID: 0 PID: 18014 Comm: syz.6.2170 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 hfsplus_get_block+0x39e/0x1670 fs/hfsplus/extents.c:260 block_read_full_folio+0x29f/0x830 fs/buffer.c:2420 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2496 do_read_cache_folio+0x358/0x590 mm/filemap.c:4096 do_read_cache_page mm/filemap.c:4162 [inline] read_cache_page+0x5d/0x170 mm/filemap.c:4171 read_mapping_page include/linux/pagemap.h:1022 [inline] hfsplus_block_allocate+0xf3/0xce0 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xb2d/0x1d70 fs/hfsplus/extents.c:464 hfsplus_get_block+0x42c/0x1670 fs/hfsplus/extents.c:245 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x737/0xae0 fs/buffer.c:2594 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314 generic_file_write_iter+0x14a/0x680 mm/filemap.c:4457 __kernel_write_iter+0x41e/0x880 fs/read_write.c:619 __kernel_write+0x106/0x170 fs/read_write.c:639 __dump_emit+0x20b/0x320 fs/coredump.c:1220 elf_core_dump+0x2bef/0x3ad0 fs/binfmt_elf.c:2063 coredump_write+0x11de/0x1980 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x369e/0x4270 fs/coredump.c:1200 get_signal+0x1107/0x1330 kernel/signal.c:3019 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x176/0x620 kernel/entry/common.c:196 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fb41499acc1 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: 00007fb414c16090 RCX: 00007fb41499acb9 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007fb414a08bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fb414c16128 R14: 00007fb414c16090 R15: 00007ffc53502b58 syz.6.2170 (18014) used greatest stack depth: 18824 bytes left