| From: Kees Cook <kees@kernel.org> |
| Subject: mm: vmalloc: actually use the in-place vrealloc region |
| Date: Thu, 15 May 2025 14:42:15 -0700 |
| |
| Patch series "mm: vmalloc: Actually use the in-place vrealloc region". |
| |
| This fixes a performance regression[1] with vrealloc()[1]. |
| |
| |
| The refactoring to not build a new vmalloc region only actually worked |
| when shrinking. Actually return the resized area when it grows. Ugh. |
| |
| Link: https://lkml.kernel.org/r/20250515214217.619685-1-kees@kernel.org |
| Fixes: a0309faf1cb0 ("mm: vmalloc: support more granular vrealloc() sizing") |
| Signed-off-by: Kees Cook <kees@kernel.org> |
| Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> |
| Closes: https://lore.kernel.org/all/20250515-bpf-verifier-slowdown-vwo2meju4cgp2su5ckj@6gi6ssxbnfqg [1] |
| Tested-by: Eduard Zingerman <eddyz87@gmail.com> |
| Tested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> |
| Tested-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> |
| Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com> |
| Reviewed-by: Danilo Krummrich <dakr@kernel.org> |
| Cc: "Erhard F." <erhard_f@mailbox.org> |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| mm/vmalloc.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/mm/vmalloc.c~mm-vmalloc-actually-use-the-in-place-vrealloc-region |
| +++ a/mm/vmalloc.c |
| @@ -4111,6 +4111,7 @@ void *vrealloc_noprof(const void *p, siz |
| 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. */ |
| _ |
