Commit d3f1b113 authored Mar 28, 2023 by Wang YanQing Committed by Greg Kroah-Hartman May 17, 2023

ubi: Fix return value overwrite issue in try_write_vid_and_data()

commit 31a149d5c13c4cbcf97de3435817263a2d8c9d6e upstream.

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: Wang YanQing <udknight@gmail.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 6f2eee54

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;
		}