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From: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
To: Andrew Morton <akpm@linux-foundation.org>,
	 Shuah Khan <shuah@kernel.org>, Dev Jain <dev.jain@arm.com>,
	 Thomas Gleixner <tglx@linutronix.de>,
	David Hildenbrand <david@redhat.com>,
	 Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
Subject: [PATCH v4 1/4] selftests/mm: virtual_address_range: mmap() without PROT_WRITE
Date: Tue, 14 Jan 2025 17:06:45 +0100	[thread overview]
Message-ID: <20250114-virtual_address_range-tests-v4-1-6fd7269934a5@linutronix.de> (raw)
In-Reply-To: <20250114-virtual_address_range-tests-v4-0-6fd7269934a5@linutronix.de>

When mapping a larger chunk than physical memory is available with
PROT_WRITE and overcommit is disabled, the mapping will fail.
This will prevent the test from running on systems with less then ~1GiB
of memory and triggering an inscrutinable test failure.
As the mappings are never written to anyways, the flag can be removed.

Fixes: 4e5ce33ceb32 ("selftests/vm: add a test for virtual address range mapping")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Dev Jain <dev.jain@arm.com>
---
 tools/testing/selftests/mm/virtual_address_range.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/virtual_address_range.c b/tools/testing/selftests/mm/virtual_address_range.c
index 2a2b69e91950a37999f606847c9c8328d79890c2..ea6ccf49ef4c552f26317c2a40b09bca1a677f8f 100644
--- a/tools/testing/selftests/mm/virtual_address_range.c
+++ b/tools/testing/selftests/mm/virtual_address_range.c
@@ -166,7 +166,7 @@ int main(int argc, char *argv[])
 	ksft_set_plan(1);
 
 	for (i = 0; i < NR_CHUNKS_LOW; i++) {
-		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ,
 			      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
 		if (ptr[i] == MAP_FAILED) {
@@ -186,7 +186,7 @@ int main(int argc, char *argv[])
 
 	for (i = 0; i < NR_CHUNKS_HIGH; i++) {
 		hint = hint_addr();
-		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ,
 			       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
 		if (hptr[i] == MAP_FAILED)

-- 
2.47.1



  reply	other threads:[~2025-01-14 16:07 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-14 16:06 [PATCH v4 0/4] selftests/mm: virtual_address_range: Reduce memory usage and avoid VM_IO access Thomas Weißschuh
2025-01-14 16:06 ` Thomas Weißschuh [this message]
2025-01-14 16:06 ` [PATCH v4 2/4] selftests/mm: virtual_address_range: Unmap chunks after validation Thomas Weißschuh
2025-01-14 16:06 ` [PATCH v4 3/4] selftests/mm: vm_util: Split up /proc/self/smaps parsing Thomas Weißschuh
2025-01-14 16:06 ` [PATCH v4 4/4] selftests/mm: virtual_address_range: Avoid reading from VM_IO mappings Thomas Weißschuh
2025-01-14 16:53   ` David Hildenbrand
2025-01-14 16:49 ` [PATCH v4 0/4] selftests/mm: virtual_address_range: Reduce memory usage and avoid VM_IO access David Hildenbrand

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