On Sat, Jun 18, 2022 at 07:57:01PM +0800, Coly Li wrote:
2022年6月18日 19:37，Pavel Machek pavel@ucw.cz 写道：
Hi!
Fixes: bc082a55d25c ("bcache: fix inaccurate io state for detached
...
+++ b/drivers/md/bcache/request.c @@ -1107,6 +1107,12 @@ static void detached_dev_do_request(struct bcache_device *d, struct bio *bio, * which would call closure_get(&dc->disk.cl) */ ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO);
if (!ddip) {bio->bi_status = BLK_STS_RESOURCE;bio->bi_end_io(bio);return;}ddip->d = d; /* Count on the bcache device */ ddip->orig_bdev = orig_bdev;So... for patch to make any difference, memory allocation has to fail and ddip has to be NULL.
Before the patch, it would oops in "ddip->d = d;". With the patch, you do some kind of error handling. Even if it is buggy, it should not do more harm than immediate oops.
I just receive this single email and don’t have any idea for the context and what the problem is. Where can I see the whole conversation?
Discussion happened on stable@vger.kernel.org mailing lists, archives should be easily available. Copy went to lkml, too.
Hi Pavel and Greg,
Thanks for the hint, I see the context. I cannot tell the direct reason of the kfence regression, but it is worthy to have this patch in,
- commit 7d6b902ea0e0 ("bcache: memset on stack variables in bch_btree_check() and bch_sectors_dirty_init()”)
I am not sure whether it is directly related to the kfence issue, it corrects potential unexpected stack state in some condition. Hope it may help a bit.
Added where?
confused,
greg k-h