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selftests/mm: report SKIP in pfnmap if a check fails

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pfnmap currently checks the target file in FIXTURE_SETUP(pfnmap), meaning
once for every test, and skips the test if any check fails.

The target file is the same for every test so this is a little overkill. 
More importantly, this approach means that the whole suite will report
PASS even if all the tests are skipped because kernel configuration (e.g. 
CONFIG_STRICT_DEVMEM=y) prevented /dev/mem from being mapped, for
instance.

Let's ensure that KSFT_SKIP is returned as exit code if any check fails by
performing the checks in pfnmap_init(), run once.  That function also
takes care of finding the offset of the pages to be mapped and saves it in
a global.  The file is now opened only once and the fd saved in a global,
but it is still mapped/unmapped for every test, as some of them modify the
mapping.

Link: https://lkml.kernel.org/r/20260122170224.4056513-10-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Usama Anjum <Usama.Anjum@arm.com>
Cc: wang lian <lianux.mm@gmail.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Kevin Brodsky 2026-01-22 17:02:24 +00:00 • committed by Andrew Morton
parent 148e587953
commit fde8353121
1 changed files with 53 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

84
tools/testing/selftests/mm/pfnmap.c
View file

@ -25,8 +25,12 @@
#include "kselftest_harness.h"
#include "vm_util.h"
#define DEV_MEM_NPAGES 2
static sigjmp_buf sigjmp_buf_env;
static char *file = "/dev/mem";
static off_t file_offset;
static int fd;
static void signal_handler(int sig)
{
@ -88,7 +92,7 @@ static int find_ram_target(off_t *offset,
break;
/* We need two pages. */
if (end > start + 2 * pagesize) {
if (end > start + DEV_MEM_NPAGES * pagesize) {
fclose(file);
*offset = start;
return 0;
@ -97,11 +101,48 @@ static int find_ram_target(off_t *offset,
return -ENOENT;
}
static void pfnmap_init(void)
{
size_t pagesize = getpagesize();
size_t size = DEV_MEM_NPAGES * pagesize;
void *addr;
if (strncmp(file, "/dev/mem", strlen("/dev/mem")) == 0) {
int err = find_ram_target(&file_offset, pagesize);
if (err)
ksft_exit_skip("Cannot find ram target in '/proc/iomem': %s\n",
strerror(-err));
} else {
file_offset = 0;
}
fd = open(file, O_RDONLY);
if (fd < 0)
ksft_exit_skip("Cannot open '%s': %s\n", file, strerror(errno));
/*
* Make sure we can map the file, and perform some basic checks; skip
* the whole suite if anything goes wrong.
* A fresh mapping is then created for every test case by
* FIXTURE_SETUP(pfnmap).
*/
addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, file_offset);
if (addr == MAP_FAILED)
ksft_exit_skip("Cannot mmap '%s': %s\n", file, strerror(errno));
if (!check_vmflag_pfnmap(addr))
ksft_exit_skip("Invalid file: '%s'. Not pfnmap'ed\n", file);
if (test_read_access(addr, size, pagesize))
ksft_exit_skip("Cannot read-access mmap'ed '%s'\n", file);
munmap(addr, size);
}
FIXTURE(pfnmap)
{
off_t offset;
size_t pagesize;
int dev_mem_fd;
char *addr1;
size_t size1;
char *addr2;
@ -112,31 +153,10 @@ FIXTURE_SETUP(pfnmap)
{
self->pagesize = getpagesize();
if (strncmp(file, "/dev/mem", strlen("/dev/mem")) == 0) {
/* We'll require two physical pages throughout our tests ... */
if (find_ram_target(&self->offset, self->pagesize))
SKIP(return,
"Cannot find ram target in '/proc/iomem'\n");
} else {
self->offset = 0;
}
self->dev_mem_fd = open(file, O_RDONLY);
if (self->dev_mem_fd < 0)
SKIP(return, "Cannot open '%s'\n", file);
self->size1 = self->pagesize * 2;
self->size1 = DEV_MEM_NPAGES * self->pagesize;
self->addr1 = mmap(NULL, self->size1, PROT_READ, MAP_SHARED,
self->dev_mem_fd, self->offset);
if (self->addr1 == MAP_FAILED)
SKIP(return, "Cannot mmap '%s'\n", file);
if (!check_vmflag_pfnmap(self->addr1))
SKIP(return, "Invalid file: '%s'. Not pfnmap'ed\n", file);
/* ... and want to be able to read from them. */
if (test_read_access(self->addr1, self->size1, self->pagesize))
SKIP(return, "Cannot read-access mmap'ed '%s'\n", file);
fd, file_offset);
ASSERT_NE(self->addr1, MAP_FAILED);
self->size2 = 0;
self->addr2 = MAP_FAILED;
@ -148,8 +168,6 @@ FIXTURE_TEARDOWN(pfnmap)
munmap(self->addr2, self->size2);
if (self->addr1 != MAP_FAILED)
munmap(self->addr1, self->size1);
if (self->dev_mem_fd >= 0)
close(self->dev_mem_fd);
}
TEST_F(pfnmap, madvise_disallowed)
@ -189,7 +207,7 @@ TEST_F(pfnmap, munmap_split)
*/
self->size2 = self->pagesize;
self->addr2 = mmap(NULL, self->pagesize, PROT_READ, MAP_SHARED,
self->dev_mem_fd, self->offset);
fd, file_offset);
ASSERT_NE(self->addr2, MAP_FAILED);
}
@ -259,8 +277,12 @@ int main(int argc, char **argv)
if (strcmp(argv[i], "--") == 0) {
if (i + 1 < argc && strlen(argv[i + 1]) > 0)
file = argv[i + 1];
return test_harness_run(i, argv);
argc = i;
break;
}
}
pfnmap_init();
return test_harness_run(argc, argv);
}