Re: [syzbot] [crypto?] KMSAN: uninit-value in adiantum_crypt

[syzbot]

Hello,

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

=====================================================
BUG: KMSAN: uninit-value in subshift lib/crypto/aes.c:150 [inline]
BUG: KMSAN: uninit-value in aes_encrypt+0x1239/0x1960 lib/crypto/aes.c:283
subshift lib/crypto/aes.c:150 [inline]
aes_encrypt+0x1239/0x1960 lib/crypto/aes.c:283
aesti_encrypt+0x7d/0xf0 crypto/aes_ti.c:31
cipher_crypt_one+0x120/0x2e0 crypto/cipher.c:75
crypto_cipher_encrypt_one+0x33/0x40 crypto/cipher.c:82
adiantum_crypt+0x948/0xe70 crypto/adiantum.c:385
adiantum_encrypt+0x33/0x40 crypto/adiantum.c:421
crypto_skcipher_encrypt+0x18a/0x1e0 crypto/skcipher.c:444
fscrypt_crypt_data_unit+0x38e/0x590 fs/crypto/crypto.c:139
fscrypt_encrypt_pagecache_blocks+0x430/0x900 fs/crypto/crypto.c:197
ext4_bio_write_folio+0x1383/0x30d0 fs/ext4/page-io.c:552
mpage_submit_folio+0x399/0x3d0 fs/ext4/inode.c:2087
mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2520 [inline]
ext4_do_writepages+0x3c93/0x77a0 fs/ext4/inode.c:2932
ext4_writepages+0x338/0x870 fs/ext4/inode.c:3026
do_writepages+0x3f2/0x860 mm/page-writeback.c:2598
__writeback_single_inode+0x101/0x1190 fs/fs-writeback.c:1737
writeback_sb_inodes+0xb2d/0x1f10 fs/fs-writeback.c:2030
wb_writeback+0x4ce/0xc00 fs/fs-writeback.c:2216
wb_do_writeback fs/fs-writeback.c:2363 [inline]
wb_workfn+0x397/0x1910 fs/fs-writeback.c:2403
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3340
worker_thread+0xedf/0x1590 kernel/workqueue.c:3421
kthread+0xd5c/0xf00 kernel/kthread.c:463
ret_from_fork+0x208/0x710 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Uninit was stored to memory at:
le128_add crypto/adiantum.c:191 [inline]
adiantum_crypt+0xd06/0xe70 crypto/adiantum.c:381
adiantum_encrypt+0x33/0x40 crypto/adiantum.c:421
crypto_skcipher_encrypt+0x18a/0x1e0 crypto/skcipher.c:444
fscrypt_crypt_data_unit+0x38e/0x590 fs/crypto/crypto.c:139
fscrypt_encrypt_pagecache_blocks+0x430/0x900 fs/crypto/crypto.c:197
ext4_bio_write_folio+0x1383/0x30d0 fs/ext4/page-io.c:552
mpage_submit_folio+0x399/0x3d0 fs/ext4/inode.c:2087
mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2520 [inline]
ext4_do_writepages+0x3c93/0x77a0 fs/ext4/inode.c:2932
ext4_writepages+0x338/0x870 fs/ext4/inode.c:3026
do_writepages+0x3f2/0x860 mm/page-writeback.c:2598
__writeback_single_inode+0x101/0x1190 fs/fs-writeback.c:1737
writeback_sb_inodes+0xb2d/0x1f10 fs/fs-writeback.c:2030
wb_writeback+0x4ce/0xc00 fs/fs-writeback.c:2216
wb_do_writeback fs/fs-writeback.c:2363 [inline]
wb_workfn+0x397/0x1910 fs/fs-writeback.c:2403
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3340
worker_thread+0xedf/0x1590 kernel/workqueue.c:3421
kthread+0xd5c/0xf00 kernel/kthread.c:463
ret_from_fork+0x208/0x710 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Uninit was stored to memory at:
adiantum_crypt+0x531/0xe70 crypto/adiantum.c:369
adiantum_encrypt+0x33/0x40 crypto/adiantum.c:421
crypto_skcipher_encrypt+0x18a/0x1e0 crypto/skcipher.c:444
fscrypt_crypt_data_unit+0x38e/0x590 fs/crypto/crypto.c:139
fscrypt_encrypt_pagecache_blocks+0x430/0x900 fs/crypto/crypto.c:197
ext4_bio_write_folio+0x1383/0x30d0 fs/ext4/page-io.c:552
mpage_submit_folio+0x399/0x3d0 fs/ext4/inode.c:2087
mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2520 [inline]
ext4_do_writepages+0x3c93/0x77a0 fs/ext4/inode.c:2932
ext4_writepages+0x338/0x870 fs/ext4/inode.c:3026
do_writepages+0x3f2/0x860 mm/page-writeback.c:2598
__writeback_single_inode+0x101/0x1190 fs/fs-writeback.c:1737
writeback_sb_inodes+0xb2d/0x1f10 fs/fs-writeback.c:2030
wb_writeback+0x4ce/0xc00 fs/fs-writeback.c:2216
wb_do_writeback fs/fs-writeback.c:2363 [inline]
wb_workfn+0x397/0x1910 fs/fs-writeback.c:2403
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xb91/0x1d80 kernel/workqueue.c:3340
worker_thread+0xedf/0x1590 kernel/workqueue.c:3421
kthread+0xd5c/0xf00 kernel/kthread.c:463
ret_from_fork+0x208/0x710 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Uninit was created at:
__alloc_frozen_pages_noprof+0x421/0xab0 mm/page_alloc.c:5233
alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2486
alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
alloc_pages_noprof mm/mempolicy.c:2577 [inline]
folio_alloc_noprof+0x109/0x360 mm/mempolicy.c:2587
filemap_alloc_folio_noprof+0xda/0x480 mm/filemap.c:1013
__filemap_get_folio_mpol+0xb4f/0x1960 mm/filemap.c:2006
__filemap_get_folio include/linux/pagemap.h:763 [inline]
write_begin_get_folio include/linux/pagemap.h:789 [inline]
ext4_write_begin+0x6d3/0x2d70 fs/ext4/inode.c:1323
ext4_da_write_begin+0x75e/0x1430 fs/ext4/inode.c:3130
generic_perform_write+0x365/0x1050 mm/filemap.c:4314
ext4_buffered_write_iter+0x61a/0xce0 fs/ext4/file.c:299
ext4_file_write_iter+0x2a2/0x3d90 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0xbe2/0x15d0 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+0x2ab/0x3b0 fs/read_write.c:798
x64_sys_call+0xbaf/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:19
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 3691 Comm: kworker/u8:20 Not tainted syzkaller #0 PREEMPT(none)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-7:0)
=====================================================


Tested on:

commit: 4a298a43 Merge tag 'smp-urgent-2025-12-12' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=177909c2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f7b71d5ee1eca763
dashboard link: https://syzkaller.appspot.com/bug?extid=703d8a2cd20971854b06
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=15cb9e1a580000