Re: [RFC PATCH 0/7] k[v]free_rcu() improvements

[Harry Yoo <harry.yoo@oracle.com>]

On Fri, Feb 06, 2026 at 05:33:52PM -0800, Paul E. McKenney wrote:
> On Sat, Feb 07, 2026 at 10:21:26AM +0900, Harry Yoo wrote:
> > On Fri, Feb 06, 2026 at 04:16:46PM -0800, Paul E. McKenney wrote:
> > > On Fri, Feb 06, 2026 at 06:34:03PM +0900, Harry Yoo wrote:
> > > > These are a few improvements for k[v]free_rcu() API, which were suggested
> > > > by Alexei Starovoitov.
> > > > 
> > > > [ To kmemleak folks: I'm going to teach delete_object_full() and
> > > >   paint_ptr() to ignore cases when the object does not exist.
> > > >   Could you please let me know if the way it's done in patch 3
> > > >   looks good? Only part 2 is relevant to you. ]
> > > 
> > > On what commit should I apply this series?
> > 
> > It's based on Vlastimil's slab/for-next:
> > 
> > bc33906024eb Merge branch 'slab/for-7.0/sheaves' into slab/for-next
> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/log/?h=slab/for-next
> > 
> > > I get conflicts on top of -rcu
> > > (no surprise there) and build errors on top of next-20260205.
> > 
> > Interesting, I don't get build errors when applied it on top of next-20260205.
> 
> Here you go!
> 
> Here is my repeat-by for these build errors, perhaps a .config issue
> or difference:
> 
> tools/testing/selftests/rcutorture/bin/torture.sh --do-none --do-kvfree --do-kasan

Haha, thanks! The kernel test robot reported the same issue on the
weekend. It seems I forgot to include <linux/irq_work.h> and it's
accidentally included on my environment.

Adding #include <linux/irq_work.h> in mm/slab_common.c fixes this.
Will adjust next time I post it, thanks!

-- 
Cheers,
Harry / Hyeonggon

> 							Thanx, Paul
> 
> ------------------------------------------------------------------------
> 
> mm/slab_common.c:1475:21: error: implicit declaration of function ‘IRQ_WORK_INIT’; did you mean ‘IRQ_WORK_VECTOR’? [-Werror=implicit-function-declaration]
>  1475 |         .irq_work = IRQ_WORK_INIT(defer_kfree_rcu),
>       |                     ^~~~~~~~~~~~~
>       |                     IRQ_WORK_VECTOR
> mm/slab_common.c:1475:21: error: initialization of ‘struct llist_node *’ from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion]
> mm/slab_common.c:1475:21: note: (near initialization for ‘krc.irq_work.node.llist.next’)
> mm/slab_common.c:1475:21: error: initializer element is not constant
> mm/slab_common.c:1475:21: note: (near initialization for ‘krc.irq_work.node.llist.next’)
>   CC      drivers/tty/pty.o
> mm/slab_common.c:1477:17: error: implicit declaration of function ‘IRQ_WORK_INIT_LAZY’ [-Werror=implicit-function-declaration]
>  1477 |                 IRQ_WORK_INIT_LAZY(sched_monitor_irq_work),
>       |                 ^~~~~~~~~~~~~~~~~~
> mm/slab_common.c:1477:17: error: initialization of ‘struct llist_node *’ from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion]
> mm/slab_common.c:1477:17: note: (near initialization for ‘krc.sched_monitor_irq_work.node.llist.next’)
> mm/slab_common.c:1477:17: error: initializer element is not constant
> mm/slab_common.c:1477:17: note: (near initialization for ‘krc.sched_monitor_irq_work.node.llist.next’)
>   CC      drivers/tty/tty_audit.o
>   CC      net/ethtool/eee.o
> mm/slab_common.c: In function ‘kvfree_call_rcu_ptr’:
> mm/slab_common.c:2097:25: error: implicit declaration of function ‘irq_work_queue’; did you mean ‘drain_workqueue’? [-Werror=implicit-function-declaration]
>  2097 |                         irq_work_queue(&krcp->sched_monitor_irq_work);
>       |                         ^~~~~~~~~~~~~~
>       |                         drain_workqueue
>