====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.7.673/9900 is trying to acquire lock: ffff88805a5ba0f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xa7/0xd10 fs/hfsplus/bitmap.c:35 but task is already holding lock: ffff8880589a1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1f8/0x1c30 fs/hfsplus/extents.c:453 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 hfsplus_get_block+0x398/0x1600 fs/hfsplus/extents.c:260 block_read_full_folio+0x29f/0x830 fs/buffer.c:2420 filemap_read_folio+0x117/0x380 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:1011 [inline] hfsplus_block_allocate+0xf3/0xd10 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xa9a/0x1c30 fs/hfsplus/extents.c:464 hfsplus_get_block+0x40a/0x1600 fs/hfsplus/extents.c:245 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x78c/0xb50 fs/buffer.c:2594 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 generic_file_write_iter+0x117/0x550 mm/filemap.c:4457 __kernel_write_iter+0x428/0x910 fs/read_write.c:619 __kernel_write+0xef/0x150 fs/read_write.c:639 __dump_emit+0x206/0x310 fs/coredump.c:1220 elf_core_dump+0x2a87/0x3960 fs/binfmt_elf.c:2063 coredump_write+0x1121/0x18b0 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sbi->alloc_mutex){+.+.}-{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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 hfsplus_block_allocate+0xa7/0xd10 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xa9a/0x1c30 fs/hfsplus/extents.c:464 hfsplus_get_block+0x40a/0x1600 fs/hfsplus/extents.c:245 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x78c/0xb50 fs/buffer.c:2594 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 cont_expand_zero fs/buffer.c:2555 [inline] cont_write_begin+0x82b/0xb50 fs/buffer.c:2584 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 generic_file_write_iter+0x117/0x550 mm/filemap.c:4457 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_pwrite64 fs/read_write.c:793 [inline] __do_sys_pwrite64 fs/read_write.c:801 [inline] __se_sys_pwrite64 fs/read_write.c:798 [inline] __x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&HFSPLUS_I(inode)->extents_lock); lock(&sbi->alloc_mutex); lock(&HFSPLUS_I(inode)->extents_lock); lock(&sbi->alloc_mutex); *** DEADLOCK *** 3 locks held by syz.7.673/9900: #0: ffff88808c088420 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff88808c088420 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682 #1: ffff8880589a1738 (&sb->s_type->i_mutex_key#43){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff8880589a1738 (&sb->s_type->i_mutex_key#43){++++}-{4:4}, at: generic_file_write_iter+0xeb/0x550 mm/filemap.c:4454 #2: ffff8880589a1548 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1f8/0x1c30 fs/hfsplus/extents.c:453 stack backtrace: CPU: 1 UID: 0 PID: 9900 Comm: syz.7.673 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+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 hfsplus_block_allocate+0xa7/0xd10 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xa9a/0x1c30 fs/hfsplus/extents.c:464 hfsplus_get_block+0x40a/0x1600 fs/hfsplus/extents.c:245 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x78c/0xb50 fs/buffer.c:2594 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 cont_expand_zero fs/buffer.c:2555 [inline] cont_write_begin+0x82b/0xb50 fs/buffer.c:2584 hfsplus_write_begin+0x66/0xb0 fs/hfsplus/inode.c:48 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 generic_file_write_iter+0x117/0x550 mm/filemap.c:4457 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_pwrite64 fs/read_write.c:793 [inline] __do_sys_pwrite64 fs/read_write.c:801 [inline] __se_sys_pwrite64 fs/read_write.c:798 [inline] __x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3a08d8f749 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:00007f3a09c21038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f3a08fe6090 RCX: 00007f3a08d8f749 RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000007 RBP: 00007f3a08e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3a08fe6128 R14: 00007f3a08fe6090 R15: 00007ffe5ccf46b8