Re: [syzbot] [mm?] kernel BUG in sg_init_one

Barry Song
2024-03-18T20:42:28Z

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: e5eb28f6d1af Merge tag 'mm-nonmm-stable-2024-03-14-09-36' ..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=13043abe180000
> kernel config: https://syzkaller.appspot.com/x/.config?x=19bb57c23dffc38e
> dashboard link: https://syzkaller.appspot.com/bug?extid=adbc983a1588b7805de3
> compiler: arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: arm
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1706d231180000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ba7959180000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/8ead8862021c/non_bootable_disk-e5eb28f6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/0a7371c63ff2/vmlinux-e5eb28f6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/7539441b4add/zImage-e5eb28f6.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+adbc983a1588b7805de3@syzkaller.appspotmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e5eb28f6d1afebed4bb7d740a797d0390bd3a357

diff --git a/mm/zswap.c b/mm/zswap.c
index 9dec853647c8..47c0386caba2 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1086,7 +1086,8 @@ static void zswap_decompress(struct zswap_entry *entry, struct page *page)
zpool_unmap_handle(zpool, entry->handle);
}

- sg_init_one(&input, src, entry->length);
+ sg_init_table(&input, 1);
+ sg_set_page(&input, kmap_to_page(src), entry->length, offset_in_page(src));
sg_init_table(&output, 1);
sg_set_page(&output, page, PAGE_SIZE, 0);
acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE);