> On 10 Oct 2016, at 21:50, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: > > On Mon, Oct 10, 2016 at 3:13 PM, Nikolay Borisov <kernel@xxxxxxxx> wrote: >> >> >> On 10/10/2016 04:11 PM, Yan, Zheng wrote: >>> >>>> On 10 Oct 2016, at 20:56, Nikolay Borisov <kernel@xxxxxxxx> wrote: >>>> >>>> In case __ceph_do_getattr returns an error and the retry_op in >>>> ceph_read_iter is not READ_INLINE, then it's possible to invoke >>>> __free_page on a page which is NULL, this naturally leads to a crash. >>>> This can happen when, for example, a process waiting on a MDS reply >>>> receives sigterm. >>>> >>>> Fix this by explicitly checking whether the page is set or not. >>>> >>>> Signed-off-by: Nikolay Borisov <kernel@xxxxxxxx> >>>> Link: http://www.spinics.net/lists/ceph-users/msg31592.html >>>> --- >>>> >>>> Inverted the condition, so resending with correct condition >>>> this time. >>>> >>>> fs/ceph/file.c | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c >>>> index 3c68e6aee2f0..7413313ae6c8 100644 >>>> --- a/fs/ceph/file.c >>>> +++ b/fs/ceph/file.c >>>> @@ -929,7 +929,8 @@ again: >>>> statret = __ceph_do_getattr(inode, page, >>>> CEPH_STAT_CAP_INLINE_DATA, !!page); >>>> if (statret < 0) { >>>> - __free_page(page); >>>> + if (page) >>>> + __free_page(page); >>>> if (statret == -ENODATA) { >>>> BUG_ON(retry_op != READ_INLINE); >>>> goto again; >>>> — >>> Reviewed-by: Yan, Zheng <zyan@xxxxxxxxxx> >> >> I believe this needs to also be tagged as stable. To whomever is going >> to merge it: can you please do that? > > I'll do that. Zheng, do you see any other issues with the killable > wait here? No. this change is obvious, what’s your concern? Regards Yan, Zheng > > Thanks, > > Ilya -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
