On 2018年06月21日 21:58, David Sterba wrote:
> On Wed, Jun 20, 2018 at 03:38:58PM +0800, Qu Wenruo wrote:
>> Commit f8f84b2dfda5 ("btrfs: index check-integrity state hash by a dev_t")
>> changed how btrfsic how we index device state hash.
>>
>> Now we need to access device->bdev->bd_dev, while for degraded mount
>> it's completely possible to have device->bdev as NULL, thus it will
>> trigger a NULL pointer dereference at mount time.
>>
>> Fix it by checking if the device is degraded before accessing
>> device->bdev->bd_dev.
>>
>> There are a lot of other places accessing device->bdev->bd_dev, however
>> the other call sites have either checked device->bdev, or the
>> device->bdev is passed from btrfsic_map_block(), so it won't cause harm.
>>
>> Fixes: f8f84b2dfda5 ("btrfs: index check-integrity state hash by a dev_t")
>> Signed-off-by: Qu Wenruo <w...@suse.com>
>
> Added to misc-next. As it is a fix it could go to 4.18 but I'd rather
> have a good reason for that because it's in a debugging feature.No need to push it to 4.18. Indeed it's a debug feature, and furthermore, there are tons of bugs exposed by fstests, so it's better to fix it as a large serious patchset. Thanks, Qu > >> --- >> Please note there are still quite some problem about check-integrity, >> including: >> 1) Warning for degraded mount >> 2) Meaningless empty lines output >> >> This patch will only fix the obvious NULL pointer dereference exposed by >> btrfs/027 with "check_int" mount option. > > Ok. > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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