On Fri, 25 Mar 2016, Eric Wheeler wrote: > On Thu, 24 Mar 2016, Sebastian Roesner wrote: > > I experienced a bug after upgrading to a recent kernel (4.5.0). > > > > # echo /dev/md2 > /sys/fs/bcache/register > > > > gives me a stack trace. > > > > I created a bug in the kernel bugtracker but I'm not sure if it has been > > noticed by the bcache developers: > > > > <https://bugzilla.kernel.org/show_bug.cgi?id=114871> > > The dereference appears to happen inside of bio_trim which is core block > code. In this case, it looks like bio_trim is being passed a null pointer > to *bio, but by whom? > > Please send this output: > > tail /sys/block/md2/queue/discard_* > > > Could somebody have a look? > > It could be an allocation failure in bcache that gets pushed down the > stack at registration. If that is the case, please pull these two fixes > branches which may have missed 4.5: > > git pull https://bitbucket.org/ewheelerinc/linux v4.5-rc6-bcache-fixes > git pull https://bitbucket.org/ewheelerinc/linux v4.5-rc7-bcache-fixes Sebastian, Try this patch and see if it BUGs: diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c index 86a0bb8..f6bbbce 100644 --- a/drivers/md/bcache/io.c +++ b/drivers/md/bcache/io.c @@ -24,6 +24,9 @@ struct bio *bch_bbio_alloc(struct cache_set *c) struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO); struct bio *bio = &b->bio; + BUG_ON(!b); + BUG_ON(!bio); + bio_init(bio); bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; bio->bi_max_vecs = bucket_pages(c); -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
