The commit 2d78aee426d8 ("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: 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
Signed-off-by: Wang YanQing <[email protected]>
---
drivers/mtd/ubi/eba.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 09c408c..4e32b25 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -981,10 +981,17 @@ 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) {
+ if (ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1) != 0) {
+ ubi_warn(ubi, "failed to return physical eraseblock %d",
+ pnum);
+ }
+ } else if (!err && opnum >= 0) {
+ if (ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0) != 0) {
+ ubi_warn(ubi, "failed to return physical eraseblock %d",
+ opnum);
+ }
+ }
return err;
}
--
1.8.5.6.2.g3d8a54e.dirty
On Sat, Feb 18, 2023 at 12:58:08AM +0800, Wang YanQing wrote:
> The commit 2d78aee426d8 ("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: 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
>
> Signed-off-by: Wang YanQing <[email protected]>
Hi! Miquel Raynal
What is the status about this patch?
Thanks!
----- Ursprüngliche Mail -----
> Von: "Wang YanQing" <[email protected]>
> An: "Miquel Raynal" <[email protected]>, "Boris Brezillon" <[email protected]>, "richard" <[email protected]>,
> "Vignesh Raghavendra" <[email protected]>, "linux-mtd" <[email protected]>, "linux-kernel"
> <[email protected]>
> Gesendet: Sonntag, 26. Februar 2023 15:14:06
> Betreff: Re: [PATCH] mtd: ubi: eba.c: fix return value overwrite issue in try_write_vid_and_data()
> On Sat, Feb 18, 2023 at 12:58:08AM +0800, Wang YanQing wrote:
>> The commit 2d78aee426d8 ("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: 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
>>
>> Signed-off-by: Wang YanQing <[email protected]>
>
> Hi! Miquel Raynal
>
> What is the status about this patch?
We're in the middle of the merge window. It will be applied to the fixes
branch after rc1.
Thanks,
//richard
Good catch. Maybe many of history happened unconsistent ubifs images
have related to this point. One small nit below.
> The commit 2d78aee426d8 ("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: 2d78aee426d8 ("UBI: simplify LEB write and atomic LEB change code")
>
> Signed-off-by: Wang YanQing <[email protected]>
> ---
> drivers/mtd/ubi/eba.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
> index 09c408c..4e32b25 100644
> --- a/drivers/mtd/ubi/eba.c
> +++ b/drivers/mtd/ubi/eba.c
> @@ -981,10 +981,17 @@ 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) {
> + if (ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1) != 0) {
Could we also add error code returned from ubi_wl_put_peb() in warning
message? Same with next ubifs_warn.
> + ubi_warn(ubi, "failed to return physical eraseblock %d",
> + pnum);
> + }
> + } else if (!err && opnum >= 0) {
> + if (ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0) != 0) {
> + ubi_warn(ubi, "failed to return physical eraseblock %d",
> + opnum);
> + }
> + }
>
> return err;
> }
>