[syzbot] [crypto?] KMSAN: uninit-value in chksum_update

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    453f5db0619e Merge tag 'trace-v6.7-rc7' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127054ade80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d4130d4bb32c48ef
dashboard link: https://syzkaller.appspot.com/bug?extid=9c0d9ba56264f1602420
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/09f8d17b45e5/disk-453f5db0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/384c334e26ee/vmlinux-453f5db0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c93513aa17de/bzImage-453f5db0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c0d9ba56264f1602420@xxxxxxxxxxxxxxxxxxxxxxxxx

EXT4-fs error (device loop4): __ext4_ext_dirty:202: inode #2: comm syz-executor.4: mark_inode_dirty error
=====================================================
BUG: KMSAN: uninit-value in chksum_update+0xae/0xd0 crypto/crc32c_generic.c:88
 chksum_update+0xae/0xd0 crypto/crc32c_generic.c:88
 crypto_shash_update+0x75/0xa0 crypto/shash.c:74
 ext4_chksum fs/ext4/ext4.h:2474 [inline]
 ext4_dirblock_csum fs/ext4/namei.c:382 [inline]
 ext4_dirblock_csum_set fs/ext4/namei.c:430 [inline]
 ext4_handle_dirty_dirblock+0x6d5/0x8d0 fs/ext4/namei.c:438
 add_dirent_to_buf+0x885/0x9f0 fs/ext4/namei.c:2215
 ext4_add_entry+0xcc2/0x1b30 fs/ext4/namei.c:2447
 ext4_mkdir+0xaae/0x1510 fs/ext4/namei.c:3031
 vfs_mkdir+0x49a/0x700 fs/namei.c:4106
 do_mkdirat+0x529/0x800 fs/namei.c:4129
 __do_sys_mkdir fs/namei.c:4149 [inline]
 __se_sys_mkdir fs/namei.c:4147 [inline]
 __x64_sys_mkdir+0xa1/0xe0 fs/namei.c:4147
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 ext4_chksum fs/ext4/ext4.h:2472 [inline]
 ext4_dirblock_csum fs/ext4/namei.c:382 [inline]
 ext4_dirblock_csum_set fs/ext4/namei.c:430 [inline]
 ext4_handle_dirty_dirblock+0x7d5/0x8d0 fs/ext4/namei.c:438
 add_dirent_to_buf+0x885/0x9f0 fs/ext4/namei.c:2215
 ext4_add_entry+0xcc2/0x1b30 fs/ext4/namei.c:2447
 ext4_mkdir+0xaae/0x1510 fs/ext4/namei.c:3031
 vfs_mkdir+0x49a/0x700 fs/namei.c:4106
 do_mkdirat+0x529/0x800 fs/namei.c:4129
 __do_sys_mkdir fs/namei.c:4149 [inline]
 __se_sys_mkdir fs/namei.c:4147 [inline]
 __x64_sys_mkdir+0xa1/0xe0 fs/namei.c:4147
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204
 alloc_slab_page mm/slub.c:1870 [inline]
 allocate_slab mm/slub.c:2017 [inline]
 new_slab+0x421/0x1570 mm/slub.c:2070
 ___slab_alloc+0x13db/0x33d0 mm/slub.c:3223
 __slab_alloc mm/slub.c:3322 [inline]
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc_lru+0x552/0x970 mm/slub.c:3509
 alloc_inode_sb include/linux/fs.h:2937 [inline]
 ext4_alloc_inode+0x63/0x850 fs/ext4/super.c:1408
 alloc_inode+0x83/0x440 fs/inode.c:261
 new_inode_pseudo fs/inode.c:1006 [inline]
 new_inode+0x38/0x420 fs/inode.c:1032
 __ext4_new_inode+0x297/0x79b0 fs/ext4/ialloc.c:958
 ext4_symlink+0x57e/0x1440 fs/ext4/namei.c:3398
 vfs_symlink+0x1e6/0x3e0 fs/namei.c:4464
 do_symlinkat+0x257/0x890 fs/namei.c:4490
 __do_sys_symlinkat fs/namei.c:4506 [inline]
 __se_sys_symlinkat fs/namei.c:4503 [inline]
 __x64_sys_symlinkat+0xf8/0x160 fs/namei.c:4503
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 0 PID: 5681 Comm: syz-executor.4 Not tainted 6.7.0-rc7-syzkaller-00049-g453f5db0619e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


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