> On Apr 2, 2019, at 2:11 PM, NeilBrown <neilb@xxxxxxxx> wrote:
>
> On Tue, Apr 02 2019, Yufen Yu wrote:
>
>> When doing re-add, we need to ensure rdev->mddev->pers is not NULL,
>> which can avoid potential NULL pointer derefence in fallowing
>> add_bound_rdev().
>>
>> Fixes: a6da4ef85cef ("md: re-add a failed disk")
>> Cc: Xiao Ni <xni@xxxxxxxxxx>
>> Cc: NeilBrown <neilb@xxxxxxxx>
>> Cc: <stable@xxxxxxxxxxxxxxx>
>> Signed-off-by: Yufen Yu <yuyufen@xxxxxxxxxx>
>
> Reviewed-by: NeilBrown <neilb@xxxxxxxx>
>
> Thanks,
> NeilBrown
Thanks Yufen and Neil.
I applied it to the md-next branch:
https://github.com/liu-song-6/linux/tree/md-next
Song
>
>> ---
>> drivers/md/md.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/md/md.c b/drivers/md/md.c
>> index 875b29ba5926..66b6bdf9f364 100644
>> --- a/drivers/md/md.c
>> +++ b/drivers/md/md.c
>> @@ -2859,8 +2859,10 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
>> err = 0;
>> }
>> } else if (cmd_match(buf, "re-add")) {
>> - if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1) &&
>> - rdev->saved_raid_disk >= 0) {
>> + if (!rdev->mddev->pers)
>> + err = -EINVAL;
>> + else if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1) &&
>> + rdev->saved_raid_disk >= 0) {
>> /* clear_bit is performed _after_ all the devices
>> * have their local Faulty bit cleared. If any writes
>> * happen in the meantime in the local node, they
>> --
>> 2.16.2.dirty
