[PATCH 1/2] mm: vmalloc: Actually use the in-place vrealloc region

[Kees Cook <kees@kernel.org>]

The refactoring to not build a new vmalloc region only actually worked
when shrinking. Actually return the resized area when it grows. Ugh.

Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Closes: https://lore.kernel.org/all/20250515-bpf-verifier-slowdown-vwo2meju4cgp2su5ckj@6gi6ssxbnfqg
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Tested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Fixes: a0309faf1cb0 ("mm: vmalloc: support more granular vrealloc() sizing")
Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: <linux-mm@kvack.org>
---
 mm/vmalloc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 2d7511654831..74bd00fd734d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4111,6 +4111,7 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
 		if (want_init_on_alloc(flags))
 			memset((void *)p + old_size, 0, size - old_size);
 		vm->requested_size = size;
+		return (void *)p;
 	}
 
 	/* TODO: Grow the vm_area, i.e. allocate and map additional pages. */
-- 
2.34.1