linux-kernel - [syzbot] [crypto?] KMSAN: uninit-value in fscrypt_crypt_data

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Message-ID: <68ee633c.050a0220.1186a4.002a.GAE@google.com>
Date: Tue, 14 Oct 2025 07:50:36 -0700
From: syzbot <syzbot+7add5c56bc2a14145d20@...kaller.appspotmail.com>
To: davem@...emloft.net, herbert@...dor.apana.org.au, 
	linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [crypto?] KMSAN: uninit-value in fscrypt_crypt_data_unit

Hello,

syzbot found the following issue on:

HEAD commit:    3a8660878839 Linux 6.18-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d25dcd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bbd3e7f3c2e28265
dashboard link: https://syzkaller.appspot.com/bug?extid=7add5c56bc2a14145d20
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d996feb56093/disk-3a866087.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fa6f6bc3b02a/vmlinux-3a866087.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7571083a68d6/bzImage-3a866087.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7add5c56bc2a14145d20@...kaller.appspotmail.com

EXT4-fs (loop5): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
=====================================================
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
 crypto_ecb_crypt crypto/ecb.c:23 [inline]
 crypto_ecb_encrypt2+0x142/0x300 crypto/ecb.c:40
 crypto_lskcipher_crypt_sg+0x3ac/0x930 crypto/lskcipher.c:188
 crypto_lskcipher_encrypt_sg+0x8b/0xc0 crypto/lskcipher.c:207
 crypto_skcipher_encrypt+0x111/0x1e0 crypto/skcipher.c:194
 xts_encrypt+0x2e1/0x570 crypto/xts.c:269
 crypto_skcipher_encrypt+0x18a/0x1e0 crypto/skcipher.c:195
 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 fs/ext4/inode.c:2080 [inline]
 mpage_process_page_bufs+0xf1b/0x13e0 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x1792/0x2a10 fs/ext4/inode.c:2736
 ext4_do_writepages+0x11b6/0x8020 fs/ext4/inode.c:2877
 ext4_writepages+0x338/0x870 fs/ext4/inode.c:3025
 do_writepages+0x3f2/0x860 mm/page-writeback.c:2604
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 file_write_and_wait_range+0x6f0/0x7d0 mm/filemap.c:797
 generic_buffers_fsync_noflush+0x79/0x3c0 fs/buffer.c:609
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x587/0x12f0 fs/ext4/fsync.c:147
 vfs_fsync_range+0x1a1/0x240 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3046 [inline]
 ext4_buffered_write_iter+0xae9/0xce0 fs/ext4/file.c:305
 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+0xe77/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 le128_xor include/crypto/b128ops.h:69 [inline]
 xts_xor_tweak+0x566/0xbd0 crypto/xts.c:123
 xts_xor_tweak_pre crypto/xts.c:135 [inline]
 xts_encrypt+0x278/0x570 crypto/xts.c:268
 crypto_skcipher_encrypt+0x18a/0x1e0 crypto/skcipher.c:195
 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 fs/ext4/inode.c:2080 [inline]
 mpage_process_page_bufs+0xf1b/0x13e0 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x1792/0x2a10 fs/ext4/inode.c:2736
 ext4_do_writepages+0x11b6/0x8020 fs/ext4/inode.c:2877
 ext4_writepages+0x338/0x870 fs/ext4/inode.c:3025
 do_writepages+0x3f2/0x860 mm/page-writeback.c:2604
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 file_write_and_wait_range+0x6f0/0x7d0 mm/filemap.c:797
 generic_buffers_fsync_noflush+0x79/0x3c0 fs/buffer.c:609
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x587/0x12f0 fs/ext4/fsync.c:147
 vfs_fsync_range+0x1a1/0x240 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3046 [inline]
 ext4_buffered_write_iter+0xae9/0xce0 fs/ext4/file.c:305
 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+0xe77/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x689/0xf00 mm/page_alloc.c:5206
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
 alloc_pages_noprof mm/mempolicy.c:2507 [inline]
 folio_alloc_noprof+0x109/0x360 mm/mempolicy.c:2517
 filemap_alloc_folio_noprof+0x9d/0x420 mm/filemap.c:1020
 __filemap_get_folio+0xb45/0x1930 mm/filemap.c:2012
 write_begin_get_folio include/linux/pagemap.h:784 [inline]
 ext4_write_begin+0x6d9/0x2d70 fs/ext4/inode.c:1318
 generic_perform_write+0x365/0x1050 mm/filemap.c:4242
 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+0xe77/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5879 Comm: syz.5.3882 Tainted: G        W           syzkaller #0 PREEMPT(none) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
=====================================================


---
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