On Fri, 24 Jun 2011 21:12:36 +0300 Dan Carpenter <error27@xxxxxxxxx> wrote:
> Hi Neil,
>
> In d1b053e4de0ac33 "md/raid5: Protect some more code with
> ->device_lock." we moved some debug code around and it upsets my
> static checker. Could you take a look?
>
> drivers/md/raid5.c +2183 add_stripe_bio(47)
> error: potential null derefence 'bi'.
>
> 2168 if (forwrite) {
> 2169 /* check if page is covered */
> 2170 sector_t sector = sh->dev[dd_idx].sector;
> 2171 for (bi=sh->dev[dd_idx].towrite;
> 2172 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
> 2173 bi && bi->bi_sector <= sector;
> ^^
> It looks like "bi" can be NULL at the end of this for loop.
>
>
> 2174 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
> 2175 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
> 2176 sector = bi->bi_sector + (bi->bi_size>>9);
> 2177 }
> 2178 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
> 2179 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
> 2180 }
> 2181 spin_unlock_irq(&conf->device_lock);
> 2182
> 2183 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
> 2184 (unsigned long long)bi->bi_sector,
> ^^^^^^^^^^^^^
> We dereference it here.
>
> 2185 (unsigned long long)sh->sector, dd_idx);
>
> regards,
> dan carpenter
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
Thanks Dan,
as it happens I received a patch just the day before from Namhyung Kim which
fixes that bug - so all fixed now.
Thanks,
NeilBrown
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
