loop2: 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+0xaab/0x3000 fs/buffer.c:2116
 block_write_begin fs/buffer.c:2227 [inline]
 cont_write_begin+0x10df/0x1ba0 fs/buffer.c:2566
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2493 [inline]
 cont_write_begin+0x35a/0x1ba0 fs/buffer.c:2556
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 generic_perform_write+0x3f4/0x10c0 mm/filemap.c:4103
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4220
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4246
 do_iter_readv_writev+0x93b/0xb90 fs/read_write.c:-1
 vfs_writev+0x51c/0x1420 fs/read_write.c:1055
 do_pwritev fs/read_write.c:1151 [inline]
 __do_compat_sys_pwritev2 fs/read_write.c:1296 [inline]
 __se_compat_sys_pwritev2 fs/read_write.c:1288 [inline]
 __ia32_compat_sys_pwritev2+0x43d/0x6b0 fs/read_write.c:1288
 ia32_sys_call+0x2f92/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:380
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4167 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 __do_kmalloc_node mm/slub.c:4340 [inline]
 __kmalloc_noprof+0x95f/0x1310 mm/slub.c:4353
 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+0xaab/0x3000 fs/buffer.c:2116
 block_write_begin fs/buffer.c:2227 [inline]
 cont_write_begin+0x10df/0x1ba0 fs/buffer.c:2566
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2493 [inline]
 cont_write_begin+0x35a/0x1ba0 fs/buffer.c:2556
 hfs_write_begin+0x85/0x130 fs/hfs/inode.c:52
 generic_perform_write+0x3f4/0x10c0 mm/filemap.c:4103
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4220
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4246
 do_iter_readv_writev+0x93b/0xb90 fs/read_write.c:-1
 vfs_writev+0x51c/0x1420 fs/read_write.c:1055
 do_pwritev fs/read_write.c:1151 [inline]
 __do_compat_sys_pwritev2 fs/read_write.c:1296 [inline]
 __se_compat_sys_pwritev2 fs/read_write.c:1288 [inline]
 __ia32_compat_sys_pwritev2+0x43d/0x6b0 fs/read_write.c:1288
 ia32_sys_call+0x2f92/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:380
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

CPU: 1 UID: 0 PID: 6015 Comm: syz.2.13 Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
=====================================================