I think I can NACK this patch. It was fixed properly in the kmem code. brassow On Oct 10, 2013, at 5:50 PM, H. Peter Anvin wrote: > On 09/19/2013 08:16 PM, Jonathan Brassow wrote: >> The unique portion of the kmem_cache name used when dm-raid is creating >> a RAID 4/5/6 array is the memory address of it's associated 'mddev' >> structure. This is not always unique. The memory associated >> with the 'mddev' structure can be freed and a future 'mddev' structure >> can be allocated from the exact same spot. This causes an identical >> name to the old cache to be created when kmem_cache_create is called. >> If an old name is still present amoung slab_caches due to cache merging, >> the call will fail. This is not theoretical, I see this regularly when >> performing device-mapper RAID 4/5/6 tests (although, strangely only on >> Fedora-19). >> >> Making the unique portion of the kmem_cache name based on jiffies fixes >> this problem. >> >> Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx> >> --- >> drivers/md/raid5.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c >> index 7ff4f25..f731ce9 100644 >> --- a/drivers/md/raid5.c >> +++ b/drivers/md/raid5.c >> @@ -1618,7 +1618,7 @@ static int grow_stripes(struct r5conf *conf, int num) >> "raid%d-%s", conf->level, mdname(conf->mddev)); >> else >> sprintf(conf->cache_name[0], >> - "raid%d-%p", conf->level, conf->mddev); >> + "raid%d-%llu", conf->level, get_jiffies_64()); >> sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]); >> >> conf->active_name = 0; >> > > And it is not possible to create two inside the same jiffy? Seems > unlikely at best. > > Why not just use a simple counter? > > -hpa > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href