FAILED: patch "[PATCH] selftests/mm: fix incorrect buffer->mirror size in hmm2" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 76503e1fa1a53ef041a120825d5ce81c7fe7bdd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024101401-envelope-repurpose-0c02@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

76503e1fa1a5 ("selftests/mm: fix incorrect buffer->mirror size in hmm2 double_map test")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 76503e1fa1a53ef041a120825d5ce81c7fe7bdd7 Mon Sep 17 00:00:00 2001
From: Donet Tom <[email protected]>
Date: Fri, 27 Sep 2024 00:07:52 -0500
Subject: [PATCH] selftests/mm: fix incorrect buffer->mirror size in hmm2
double_map test
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The hmm2 double_map test was failing due to an incorrect buffer->mirror size. The buffer->mirror size was 6, while buffer->ptr size was 6 * PAGE_SIZE. The test failed because the kernel's copy_to_user function was attempting to copy a 6 * PAGE_SIZE buffer to buffer->mirror. Since the size of buffer->mirror was incorrect, copy_to_user failed.

This patch corrects the buffer->mirror size to 6 * PAGE_SIZE.

Test Result without this patch
==============================
# RUN hmm2.hmm2_device_private.double_map ...
# hmm-tests.c:1680:double_map:Expected ret (-14) == 0 (0) # double_map: Test terminated by assertion
# FAIL hmm2.hmm2_device_private.double_map
not ok 53 hmm2.hmm2_device_private.double_map

Test Result with this patch
===========================
# RUN hmm2.hmm2_device_private.double_map ...
# OK hmm2.hmm2_device_private.double_map
ok 53 hmm2.hmm2_device_private.double_map

index d2cfc9b494a0..141bf63cbe05 100644
@@ -1657,7 +1657,7 @@ TEST_F(hmm2, double_map)
 
 	buffer->fd = -1;
 	buffer->size = size;
-	buffer->mirror = malloc(npages);
+	buffer->mirror = malloc(size);
 	ASSERT_NE(buffer->mirror, NULL);
 
 	/* Reserve a range of addresses. */