+ mm-vmalloc-use-physical-page-count-for-vrealloc-grow-in-place-check.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/vmalloc: use physical page count for vrealloc() grow-in-place check
has been added to the -mm mm-new branch.  Its filename is
     mm-vmalloc-use-physical-page-count-for-vrealloc-grow-in-place-check.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-use-physical-page-count-for-vrealloc-grow-in-place-check.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Shivam Kalra <shivamkalra98@zohomail.in>
Subject: mm/vmalloc: use physical page count for vrealloc() grow-in-place check
Date: Tue, 19 May 2026 17:42:15 +0530

Update the grow-in-place check in vrealloc() to compare the requested size
against the actual physical page count (vm->nr_pages) rather than the
virtual area size (alloced_size, derived from get_vm_area_size()).

Currently both values are equivalent, but the upcoming vrealloc() shrink
functionality will free pages without reducing the virtual reservation
size.  After such a shrink, the old alloced_size-based comparison would
incorrectly allow a grow-in-place operation to succeed and attempt to
access freed pages.  Switch to vm->nr_pages now so the check remains
correct once shrink support is added.

Link: https://lore.kernel.org/20260519-vmalloc-shrink-v14-2-70b96ee3e9c9@zohomail.in
Signed-off-by: Shivam Kalra <shivamkalra98@zohomail.in>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/mm/vmalloc.c~mm-vmalloc-use-physical-page-count-for-vrealloc-grow-in-place-check
+++ a/mm/vmalloc.c
@@ -4343,6 +4343,12 @@ void *vrealloc_node_align_noprof(const v
 		if (unlikely(flags & __GFP_THISNODE) && nid != NUMA_NO_NODE &&
 			     nid != page_to_nid(vmalloc_to_page(p)))
 			goto need_realloc;
+	} else {
+		/*
+		 * If p is NULL, vrealloc behaves exactly like vmalloc.
+		 * Skip the shrink and in-place grow paths.
+		 */
+		goto need_realloc;
 	}
 
 	/*
@@ -4361,7 +4367,7 @@ void *vrealloc_node_align_noprof(const v
 	/*
 	 * We already have the bytes available in the allocation; use them.
 	 */
-	if (size <= alloced_size) {
+	if (size <= vm->nr_pages << PAGE_SHIFT) {
 		/*
 		 * No need to zero memory here, as unused memory will have
 		 * already been zeroed at initial allocation time or during
_

Patches currently in -mm which might be from shivamkalra98@zohomail.in are

mm-vmalloc-extract-vm_area_free_pages-helper-from-vfree.patch
mm-vmalloc-use-physical-page-count-for-vrealloc-grow-in-place-check.patch
mm-vmalloc-use-physical-page-count-in-vread_iter-for-vm_alloc-areas.patch
mm-vmalloc-free-unused-pages-on-vrealloc-shrink.patch
lib-test_vmalloc-add-vrealloc-test-case.patch