[syzbot] [erofs?] KMSAN: uninit-value in z_erofs_lz4_decompress (3)

Thu Feb 1 22:04:32 AEDT 2024

Hello,

syzbot found the following issue on:

HEAD commit:    9f8413c4a66f Merge tag 'cgroup-for-6.8' of git://git.kerne..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13d26b1fe80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=656820e61b758b15
dashboard link: https://syzkaller.appspot.com/bug?extid=88ad8b0517a9d3bb9dc8
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11377218180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=111fd038180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/79d9f2f4b065/disk-9f8413c4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cbc68430d9c6/vmlinux-9f8413c4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9740ad9fc172/bzImage-9f8413c4.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2f79f30d7608/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+88ad8b0517a9d3bb9dc8 at syzkaller.appspotmail.com

erofs: (device loop0): z_erofs_lz4_decompress_mem: failed to decompress -42 in[46, 0] out[9000]
=====================================================
BUG: KMSAN: uninit-value in hex_dump_to_buffer+0xae9/0x10f0 lib/hexdump.c:194
 hex_dump_to_buffer+0xae9/0x10f0 lib/hexdump.c:194
 print_hex_dump+0x13d/0x3e0 lib/hexdump.c:276
 z_erofs_lz4_decompress_mem fs/erofs/decompressor.c:252 [inline]
 z_erofs_lz4_decompress+0x257e/0x2a70 fs/erofs/decompressor.c:311
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1290 [inline]
 z_erofs_decompress_queue+0x338c/0x6460 fs/erofs/zdata.c:1372
 z_erofs_decompressqueue_work+0x57/0x70 fs/erofs/zdata.c:1387
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2706
 worker_thread+0xf45/0x1490 kernel/workqueue.c:2787
 kthread+0x3ed/0x540 kernel/kthread.c:388
 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages mm/mempolicy.c:2204 [inline]
 folio_alloc+0x1da/0x380 mm/mempolicy.c:2211
 filemap_alloc_folio+0xa5/0x430 mm/filemap.c:974
 page_cache_ra_unbounded+0x2cc/0x960 mm/readahead.c:247
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order+0xfeb/0x10a0 mm/readahead.c:546
 ondemand_readahead+0x132b/0x1710 mm/readahead.c:668
 page_cache_sync_ra+0x724/0x760 mm/readahead.c:695
 page_cache_sync_readahead include/linux/pagemap.h:1283 [inline]
 filemap_get_pages+0x4c7/0x2c90 mm/filemap.c:2497
 filemap_read+0x59e/0x14d0 mm/filemap.c:2593
 generic_file_read_iter+0x136/0xad0 mm/filemap.c:2781
 __kernel_read+0x3bb/0x9e0 fs/read_write.c:434
 integrity_kernel_read+0x77/0x90 security/integrity/iint.c:221
 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline]
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline]
 ima_calc_file_hash+0x1743/0x3cc0 security/integrity/ima/ima_crypto.c:573
 ima_collect_measurement+0x44d/0xdd0 security/integrity/ima/ima_api.c:290
 process_measurement+0x2936/0x3ef0 security/integrity/ima/ima_main.c:359
 ima_file_check+0xb3/0x100 security/integrity/ima/ima_main.c:557
 do_open fs/namei.c:3624 [inline]
 path_openat+0x4d05/0x5ac0 fs/namei.c:3779
 do_filp_open+0x20d/0x590 fs/namei.c:3806
 do_sys_openat2+0x1bf/0x2f0 fs/open.c:1404
 do_sys_open fs/open.c:1419 [inline]
 __do_sys_open fs/open.c:1427 [inline]
 __se_sys_open fs/open.c:1423 [inline]
 __x64_sys_open+0x275/0x2d0 fs/open.c:1423
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 0 PID: 4393 Comm: kworker/u5:1 Not tainted 6.7.0-syzkaller-00562-g9f8413c4a66f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: erofs_worker z_erofs_decompressqueue_work
=====================================================

---
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