From: Thomas Weißschuh Date: Tue, 14 Jan 2025 16:06:45 +0000 (+0100) Subject: selftests/mm: virtual_address_range: mmap() without PROT_WRITE X-Git-Tag: v6.14-rc1~77^2~16 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a005145b9c969651a8997725e1df35c81040f76b;p=thirdparty%2Flinux.git selftests/mm: virtual_address_range: mmap() without PROT_WRITE Patch series "selftests/mm: virtual_address_range: Reduce memory", v4. The selftest started failing since commit e93d2521b27f ("x86/vdso: Split virtual clock pages into dedicated mapping") was merged. While debugging I stumbled upon some memory usage optimizations. With these test now runs on a VM with only 60MiB of memory. This patch (of 4): 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. Link: https://lkml.kernel.org/r/20250114-virtual_address_range-tests-v4-0-6fd7269934a5@linutronix.de Link: https://lkml.kernel.org/r/20250114-virtual_address_range-tests-v4-1-6fd7269934a5@linutronix.de Fixes: 4e5ce33ceb32 ("selftests/vm: add a test for virtual address range mapping") Signed-off-by: Thomas Weißschuh Acked-by: David Hildenbrand Acked-by: Dev Jain Cc: Thomas Gleixner Cc: Anshuman Khandual Cc: Shuah Khan (Samsung OSG) Cc: kernel test robot Signed-off-by: Andrew Morton --- diff --git a/tools/testing/selftests/mm/virtual_address_range.c b/tools/testing/selftests/mm/virtual_address_range.c index 2a2b69e91950a..ea6ccf49ef4c5 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)