Re: [PATCH] UBI: Fix crash in try_recover_peb()
From: Geert Uytterhoeven
Date: Mon Oct 17 2016 - 04:00:55 EST
On Thu, Oct 13, 2016 at 4:24 PM, Boris Brezillon
> On Thu, 13 Oct 2016 16:05:36 +0200
> Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>> drivers/mtd/ubi/eba.c: In function âtry_recover_pebâ:
>> drivers/mtd/ubi/eba.c:744: warning: âvid_hdrâ is used uninitialized in this function
>> The pointer vid_hdr is indeed not initialized, leading to a crash when
>> it is dereferenced.
>> Fix this by obtaining the pointer from the VID buffer, like is done
>> everywhere else.
> Indeed, I don't know how I missed that one :-/.
>> Fixes: 3291b52f9ff0acc8 ("UBI: introduce the VID buffer concept")
>> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> One minor comment below, otherwise
> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
>> Completely untested. And I know nothing about UBI ;-)
>> drivers/mtd/ubi/eba.c | 1 +
>> 1 file changed, 1 insertion(+)
>> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
>> index 95c4048a371e87b6..388e46be6ad92805 100644
>> --- a/drivers/mtd/ubi/eba.c
>> +++ b/drivers/mtd/ubi/eba.c
>> @@ -741,6 +741,7 @@ static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
>> goto out_put;
>> + vid_hdr = ubi_get_vid_hdr(vidb);
> Can you move this assignment at variable declaration time?
I can do that. However, that moves the call to ubi_get_vid_hdr() _before_
the call to ubi_io_read_vid_hdr().
While that would still work (ubi_get_vid_hdr() would just return a pointer to
the not-yet-read data), I think it's better to not move it, to prevent people
from accidentally trying to use it before the data has been read.
Do you agree?
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds