Re: [syzbot] [hfs?] KMSAN: uninit-value in __hfs_ext_cache_extent (2)

[syzbot <syzbot+d395b0c369e492a17530@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in __hfs_ext_cache_extent

loop0: detected capacity change from 0 to 64
=====================================================
BUG: KMSAN: uninit-value in __hfs_ext_read_extent fs/hfs/extent.c:161 [inline]
BUG: KMSAN: uninit-value in __hfs_ext_cache_extent+0x6d4/0x820 fs/hfs/extent.c:181
 __hfs_ext_read_extent fs/hfs/extent.c:161 [inline]
 __hfs_ext_cache_extent+0x6d4/0x820 fs/hfs/extent.c:181
 hfs_ext_read_extent fs/hfs/extent.c:204 [inline]
 hfs_get_block+0x733/0xf50 fs/hfs/extent.c:368
 __block_write_begin_int+0xa6b/0x2f80 fs/buffer.c:2121
 block_write_begin fs/buffer.c:2231 [inline]
 cont_write_begin+0xf82/0x1940 fs/buffer.c:2582
 hfs_write_begin+0x85/0x120 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2509 [inline]
 cont_write_begin+0x32f/0x1940 fs/buffer.c:2572
 hfs_write_begin+0x85/0x120 fs/hfs/inode.c:52
 hfs_file_truncate+0x1a5/0xd30 fs/hfs/extent.c:496
 hfs_inode_setattr+0x998/0xab0 fs/hfs/inode.c:654
 notify_change+0x1a8e/0x1b80 fs/attr.c:503
 do_truncate+0x22a/0x2b0 fs/open.c:65
 vfs_truncate+0x5d4/0x680 fs/open.c:111
 do_sys_truncate+0x104/0x240 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __x64_sys_truncate+0x6c/0xa0 fs/open.c:144
 x64_sys_call+0x2ce3/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:77
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4092 [inline]
 slab_alloc_node mm/slub.c:4135 [inline]
 __do_kmalloc_node mm/slub.c:4264 [inline]
 __kmalloc_noprof+0x661/0xf30 mm/slub.c:4277
 kmalloc_noprof include/linux/slab.h:882 [inline]
 hfs_find_init+0x91/0x250 fs/hfs/bfind.c:21
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_get_block+0x68d/0xf50 fs/hfs/extent.c:368
 __block_write_begin_int+0xa6b/0x2f80 fs/buffer.c:2121
 block_write_begin fs/buffer.c:2231 [inline]
 cont_write_begin+0xf82/0x1940 fs/buffer.c:2582
 hfs_write_begin+0x85/0x120 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2509 [inline]
 cont_write_begin+0x32f/0x1940 fs/buffer.c:2572
 hfs_write_begin+0x85/0x120 fs/hfs/inode.c:52
 hfs_file_truncate+0x1a5/0xd30 fs/hfs/extent.c:496
 hfs_inode_setattr+0x998/0xab0 fs/hfs/inode.c:654
 notify_change+0x1a8e/0x1b80 fs/attr.c:503
 do_truncate+0x22a/0x2b0 fs/open.c:65
 vfs_truncate+0x5d4/0x680 fs/open.c:111
 do_sys_truncate+0x104/0x240 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __x64_sys_truncate+0x6c/0xa0 fs/open.c:144
 x64_sys_call+0x2ce3/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:77
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 6040 Comm: syz.0.15 Not tainted 6.12.0-rc1-syzkaller-ge32cde8d2bd7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================


Tested on:

commit:         e32cde8d Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1106539f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b1fd45f2013d812f
dashboard link: https://syzkaller.appspot.com/bug?extid=d395b0c369e492a17530
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1363a580580000