loop4: detected capacity change from 0 to 64
=====================================================
BUG: KMSAN: uninit-value in __hfs_ext_read_extent fs/hfs/extent.c:160 [inline]
BUG: KMSAN: uninit-value in __hfs_ext_cache_extent+0x677/0x7f0 fs/hfs/extent.c:179
 __hfs_ext_read_extent fs/hfs/extent.c:160 [inline]
 __hfs_ext_cache_extent+0x677/0x7f0 fs/hfs/extent.c:179
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x451/0x1b00 fs/hfs/extent.c:401
 hfs_get_block+0x435/0x1150 fs/hfs/extent.c:353
 __block_write_begin_int+0xaae/0x3000 fs/buffer.c:2149
 block_write_begin fs/buffer.c:2260 [inline]
 cont_write_begin+0x10df/0x1ba0 fs/buffer.c:2599
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2526 [inline]
 cont_write_begin+0x35a/0x1ba0 fs/buffer.c:2589
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 generic_perform_write+0x3f7/0x10c0 mm/filemap.c:4103
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4220
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4246
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb34/0x1560 fs/read_write.c:684
 ksys_pwrite64 fs/read_write.c:791 [inline]
 __do_sys_pwrite64 fs/read_write.c:799 [inline]
 __se_sys_pwrite64 fs/read_write.c:796 [inline]
 __x64_sys_pwrite64+0x2ab/0x3b0 fs/read_write.c:796
 x64_sys_call+0x10f7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4153 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 __do_kmalloc_node mm/slub.c:4326 [inline]
 __kmalloc_noprof+0x95f/0x1310 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 hfs_find_init+0x93/0x260 fs/hfs/bfind.c:21
 hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
 hfs_extend_file+0x3c7/0x1b00 fs/hfs/extent.c:401
 hfs_get_block+0x435/0x1150 fs/hfs/extent.c:353
 __block_write_begin_int+0xaae/0x3000 fs/buffer.c:2149
 block_write_begin fs/buffer.c:2260 [inline]
 cont_write_begin+0x10df/0x1ba0 fs/buffer.c:2599
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2526 [inline]
 cont_write_begin+0x35a/0x1ba0 fs/buffer.c:2589
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 generic_perform_write+0x3f7/0x10c0 mm/filemap.c:4103
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4220
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4246
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb34/0x1560 fs/read_write.c:684
 ksys_pwrite64 fs/read_write.c:791 [inline]
 __do_sys_pwrite64 fs/read_write.c:799 [inline]
 __se_sys_pwrite64 fs/read_write.c:796 [inline]
 __x64_sys_pwrite64+0x2ab/0x3b0 fs/read_write.c:796
 x64_sys_call+0x10f7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 6578 Comm: syz.4.149 Not tainted 6.15.0-rc6-syzkaller-00173-gf1f2797f8a24 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
=====================================================