+ mm-madvise-split-out-madvise-input-validity-check.patch added to mm-unstable branch

+ mm-madvise-split-out-madvise-input-validity-check.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/madvise: split out madvise input validity check
has been added to the -mm mm-unstable branch.  Its filename is
     mm-madvise-split-out-madvise-input-validity-check.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-madvise-split-out-madvise-input-validity-check.patch

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

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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/madvise: split out madvise input validity check
Date: Wed, 5 Feb 2025 22:15:15 -0800

Split out the madvise parameters validation logic from do_madvise(), for
easy reuse of the logic from a future change.

Link: https://lkml.kernel.org/r/20250206061517.2958-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |   32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

--- a/mm/madvise.c~mm-madvise-split-out-madvise-input-validity-check
+++ a/mm/madvise.c
@@ -1601,6 +1601,27 @@ static void madvise_unlock(struct mm_str
 		mmap_read_unlock(mm);
 }
 
+static bool is_valid_madvise(unsigned long start, size_t len_in, int behavior)
+{
+	size_t len;
+
+	if (!madvise_behavior_valid(behavior))
+		return false;
+
+	if (!PAGE_ALIGNED(start))
+		return false;
+	len = PAGE_ALIGN(len_in);
+
+	/* Check to see whether len was rounded up from small -ve to zero */
+	if (len_in && !len)
+		return false;
+
+	if (start + len < start)
+		return false;
+
+	return true;
+}
+
 /*
  * The madvise(2) system call.
  *
@@ -1680,20 +1701,11 @@ int do_madvise(struct mm_struct *mm, uns
 	size_t len;
 	struct blk_plug plug;
 
-	if (!madvise_behavior_valid(behavior))
+	if (!is_valid_madvise(start, len_in, behavior))
 		return -EINVAL;
 
-	if (!PAGE_ALIGNED(start))
-		return -EINVAL;
 	len = PAGE_ALIGN(len_in);
-
-	/* Check to see whether len was rounded up from small -ve to zero */
-	if (len_in && !len)
-		return -EINVAL;
-
 	end = start + len;
-	if (end < start)
-		return -EINVAL;
 
 	if (end == start)
 		return 0;
_

Patches currently in -mm which might be from sj@kernel.org are

mm-madvise-split-out-mmap-locking-operations-for-madvise.patch
mm-madvise-split-out-madvise-input-validity-check.patch
mm-madvise-split-out-madvise-behavior-execution.patch
mm-madvise-remove-redundant-mmap_lock-operations-from-process_madvise.patch