On 5/12/21 5:50 PM, Greg Kroah-Hartman wrote:
On Wed, May 12, 2021 at 05:35:28PM +0200, Vlastimil Babka wrote:
On 5/12/21 4:50 PM, Greg Kroah-Hartman wrote:
From: Vlastimil Babka vbabka@suse.cz
[ Upstream commit 1f0723a4c0df36cbdffc6fac82cd3c5d57e06d66 ]
Commit ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") introduced a static key to optimize the case where no debugging is enabled for any cache. The static key is enabled when slub_debug boot parameter is passed, or CONFIG_SLUB_DEBUG_ON enabled.
However, some caches might be created with one or more debugging flags explicitly passed to kmem_cache_create(), and the commit missed this. Thus the debugging functionality would not be actually performed for these caches unless the static key gets enabled by boot param or config.
This patch fixes it by checking for debugging flags passed to kmem_cache_create() and enabling the static key accordingly.
Note such explicit debugging flags should not be used outside of debugging and testing as they will now enable the static key globally. btrfs_init_cachep() creates a cache with SLAB_RED_ZONE but that's a mistake that's being corrected [1]. rcu_torture_stats() creates a cache with SLAB_STORE_USER, but that is a testing module so it's OK and will start working as intended after this patch.
Also note that in case of backports to kernels before v5.12 that don't have 59450bbc12be ("mm, slab, slub: stop taking cpu hotplug lock"), static_branch_enable_cpuslocked() should be used.
[1] https://lore.kernel.org/linux-btrfs/20210315141824.26099-1-dsterba@suse.com/
Link: https://lkml.kernel.org/r/20210315153415.24404-1-vbabka@suse.cz Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()") Signed-off-by: Vlastimil Babka vbabka@suse.cz Reported-by: Oliver Glitta glittao@gmail.com Acked-by: David Rientjes rientjes@google.com Cc: Christoph Lameter cl@linux.com Cc: Pekka Enberg penberg@kernel.org Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: "Paul E. McKenney" paulmck@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org
Uh, rather not release this to stable without the followup fix: https://lore.kernel.org/linux-mm/20210504120019.26791-1-vbabka@suse.cz/
Is that in Linus's tree yet? If so, what is the git id?
No, it's in mmotm, so no git id yet, but should make it to Linus during 5.13 rc's.
thanks,
greg k-h