Merge tag 'slab-for-6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab fix from Vlastimil Babka:

 - A stable fix for kmalloc_nolock() in non-preemptible contexts on
   PREEMPT_RT (Swaraj Gaikwad)

* tag 'slab-for-6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  slab: fix kmalloc_nolock() context check for PREEMPT_RT

Author: torvalds

mm/slub.c

@@ -5694,8 +5694,12 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node)
 	if (unlikely(!size))
 		return ZERO_SIZE_PTR;
 
-	if (IS_ENABLED(CONFIG_PREEMPT_RT) && (in_nmi() || in_hardirq()))
-		/* kmalloc_nolock() in PREEMPT_RT is not supported from irq */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && !preemptible())
+		/*
+		 * kmalloc_nolock() in PREEMPT_RT is not supported from
+		 * non-preemptible context because local_lock becomes a
+		 * sleeping lock on RT.
+		 */
 		return NULL;
 retry:
 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))