Commit 400e6ebf authored by Wang YanQing's avatar Wang YanQing Committed by ZhaoLong Wang
Browse files

ubi: Fix return value overwrite issue in try_write_vid_and_data() 

mainline inclusion
from mainline-v6.2-rc1
commit 31a149d5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7JO2R
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=31a149d5c13c4cbcf97de3435817263a2d8c9d6e



----------------------------------------

The commit 2d78aee4 ("UBI: simplify LEB write and atomic LEB change code")
adds helper function, try_write_vid_and_data(), to simplify the code, but this
helper function has bug, it will return 0 (success) when ubi_io_write_vid_hdr()
or the ubi_io_write_data() return error number (-EIO, etc), because the return
value of ubi_wl_put_peb() will overwrite the original return value.

This issue will cause unexpected data loss issue, because the caller of this
function and UBIFS willn't know the data is lost.

Fixes: 2d78aee4 ("UBI: simplify LEB write and atomic LEB change code")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarWang YanQing <udknight@gmail.com>
Reviewed-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
Signed-off-by: default avatarZhaoLong Wang <wangzhaolong1@huawei.com>
parent 32613ac5

drivers/mtd/ubi/eba.c

+14 −5
Original line number Diff line number Diff line
@@ -947,7 +947,7 @@ static int try_write_vid_and_data(struct ubi_volume *vol, int lnum, 
				  int offset, int len)

{

	struct ubi_device *ubi = vol->ubi;

	int pnum, opnum, err, vol_id = vol->vol_id;

	int pnum, opnum, err, err2, vol_id = vol->vol_id;



	pnum = ubi_wl_get_peb(ubi);

	if (pnum < 0) {
@@ -982,10 +982,19 @@ static int try_write_vid_and_data(struct ubi_volume *vol, int lnum, 
out_put:

	up_read(&ubi->fm_eba_sem);



	if (err && pnum >= 0)

		err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);

	else if (!err && opnum >= 0)

		err = ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0);

	if (err && pnum >= 0) {

		err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);

		if (err2) {

			ubi_warn(ubi, "failed to return physical eraseblock %d, error %d",

				 pnum, err2);

		}

	} else if (!err && opnum >= 0) {

		err2 = ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0);

		if (err2) {

			ubi_warn(ubi, "failed to return physical eraseblock %d, error %d",

				 opnum, err2);

		}

	}



	return err;

}