On 9/19/22 08:50, Feng Tang wrote:
On Mon, Sep 19, 2022 at 05:12:38PM +0800, Vlastimil Babka wrote:
On 9/19/22 05:12, Feng Tang wrote:
[...]
The cause is inside kmem_cache_destroy():
kmem_cache_destroy
acquire lock/mutex
shutdown_cache
schedule_work(kmem_cache_release) (if RCU flag set)
release lock/mutex
kmem_cache_release (if RCU flag set)
^ not set
I've fixed that up.
Oops.. Thanks for catching it!
in some certain timing, the scheduled work could be run before
the next RCU flag checking which will get a wrong state.
Fix it by caching the RCU flag inside protected area, just like 'refcnt'
Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
Thanks!
---
note:
The error only happens on linux-next tree, and not in Linus' tree,
which already has Waiman's commit:
0495e337b703 ("mm/slab_common: Deleting kobject in kmem_cache_destroy()
without holding slab_mutex/cpu_hotplug_lock")
Actually that commit is already in Linus' rc5 too, so I will send your fix
this week too. Added a Fixes: 0495e337b703 (...) too.
Got it, thanks
- Feng
Thanks for catching this bug.
Reviewed-by: Waiman Long <longman@xxxxxxxxxx>
Cheers,
Longman
