| Message ID | 20250320063903.2685882-3-avagin@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fs/proc: extend the PAGEMAP_SCAN ioctl to report | expand |
On Thu, Mar 20, 2025 at 06:39:03AM +0000, Andrei Vagin wrote: > From: Andrei Vagin <avagin@gmail.com> > > Add a selftest to verify the PAGEMAP_SCAN ioctl correctly reports guard > regions using the newly introduced PAGE_IS_GUARD flag. > > Signed-off-by: Andrei Vagin <avagin@gmail.com> > --- > tools/testing/selftests/mm/guard-regions.c | 53 ++++++++++++++++++++++ > 1 file changed, 53 insertions(+) > > diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c > index 0c7183e8b661..24e09092fda5 100644 > --- a/tools/testing/selftests/mm/guard-regions.c > +++ b/tools/testing/selftests/mm/guard-regions.c > @@ -8,6 +8,7 @@ > #include <fcntl.h> > #include <linux/limits.h> > #include <linux/userfaultfd.h> > +#include <linux/fs.h> This is insufficient, you also need to update tools/include/uapi/linux/fs.h - we don't want to have to rely on make headers for these tests. Basically just: cp include/uapi/linux/fs.h tools/include/uapi/linux/fs.h And commit this (you can see format of commit messages like this in git log for that file). Thanks! > #include <setjmp.h> > #include <signal.h> > #include <stdbool.h> > @@ -2079,4 +2080,56 @@ TEST_F(guard_regions, pagemap) > ASSERT_EQ(munmap(ptr, 10 * page_size), 0); > } > > +/* > + * Assert that PAGEMAP_SCAN correctly reports guard region ranges. > + */ > +TEST_F(guard_regions, pagemap_scan) > +{ > + const unsigned long page_size = self->page_size; > + struct page_region pm_regs[10]; > + struct pm_scan_arg pm_scan_args = { > + .size = sizeof(struct pm_scan_arg), > + .category_anyof_mask = PAGE_IS_GUARD, > + .return_mask = PAGE_IS_GUARD, > + .vec = (long)&pm_regs, > + .vec_len = ARRAY_SIZE(pm_regs), > + }; Yeah this interface is quite nice actually... :) > + int proc_fd, i; > + char *ptr; > + > + proc_fd = open("/proc/self/pagemap", O_RDONLY); > + ASSERT_NE(proc_fd, -1); > + > + ptr = mmap_(self, variant, NULL, 10 * page_size, > + PROT_READ | PROT_WRITE, 0, 0); > + ASSERT_NE(ptr, MAP_FAILED); > + > + pm_scan_args.start = (long)ptr; > + pm_scan_args.end = (long)ptr + 10 * page_size; > + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 0); > + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); > + > + /* Install a guard region in every other page. */ > + for (i = 0; i < 10; i += 2) { > + char *ptr_p = &ptr[i * page_size]; > + > + ASSERT_EQ(syscall(__NR_madvise, ptr_p, page_size, MADV_GUARD_INSTALL), 0); > + } > + > + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 5); Nit but might be worth saying that you're asserting 5 because every other over 10. As trivial as; /* Assert ioctl() returns the count of located pages */ Which I presume it does right? > + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); > + > + /* Re-read from pagemap, and assert guard regions are detected. */ > + for (i = 0; i < 5; i++) { > + long ptr_p = (long)&ptr[2 * i * page_size]; > + > + ASSERT_EQ(pm_regs[i].start, ptr_p); > + ASSERT_EQ(pm_regs[i].end, ptr_p + page_size); > + ASSERT_EQ(pm_regs[i].categories, PAGE_IS_GUARD); > + } > + > + ASSERT_EQ(close(proc_fd), 0); > + ASSERT_EQ(munmap(ptr, 10 * page_size), 0); > +} Generally test looks ok though, thanks! Passing in my setup. > + > TEST_HARNESS_MAIN > -- > 2.49.0.rc1.451.g8f38331e32-goog >
diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c index 0c7183e8b661..24e09092fda5 100644 --- a/tools/testing/selftests/mm/guard-regions.c +++ b/tools/testing/selftests/mm/guard-regions.c @@ -8,6 +8,7 @@ #include <fcntl.h> #include <linux/limits.h> #include <linux/userfaultfd.h> +#include <linux/fs.h> #include <setjmp.h> #include <signal.h> #include <stdbool.h> @@ -2079,4 +2080,56 @@ TEST_F(guard_regions, pagemap) ASSERT_EQ(munmap(ptr, 10 * page_size), 0); } +/* + * Assert that PAGEMAP_SCAN correctly reports guard region ranges. + */ +TEST_F(guard_regions, pagemap_scan) +{ + const unsigned long page_size = self->page_size; + struct page_region pm_regs[10]; + struct pm_scan_arg pm_scan_args = { + .size = sizeof(struct pm_scan_arg), + .category_anyof_mask = PAGE_IS_GUARD, + .return_mask = PAGE_IS_GUARD, + .vec = (long)&pm_regs, + .vec_len = ARRAY_SIZE(pm_regs), + }; + int proc_fd, i; + char *ptr; + + proc_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(proc_fd, -1); + + ptr = mmap_(self, variant, NULL, 10 * page_size, + PROT_READ | PROT_WRITE, 0, 0); + ASSERT_NE(ptr, MAP_FAILED); + + pm_scan_args.start = (long)ptr; + pm_scan_args.end = (long)ptr + 10 * page_size; + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 0); + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); + + /* Install a guard region in every other page. */ + for (i = 0; i < 10; i += 2) { + char *ptr_p = &ptr[i * page_size]; + + ASSERT_EQ(syscall(__NR_madvise, ptr_p, page_size, MADV_GUARD_INSTALL), 0); + } + + ASSERT_EQ(ioctl(proc_fd, PAGEMAP_SCAN, &pm_scan_args), 5); + ASSERT_EQ(pm_scan_args.walk_end, (long)ptr + 10 * page_size); + + /* Re-read from pagemap, and assert guard regions are detected. */ + for (i = 0; i < 5; i++) { + long ptr_p = (long)&ptr[2 * i * page_size]; + + ASSERT_EQ(pm_regs[i].start, ptr_p); + ASSERT_EQ(pm_regs[i].end, ptr_p + page_size); + ASSERT_EQ(pm_regs[i].categories, PAGE_IS_GUARD); + } + + ASSERT_EQ(close(proc_fd), 0); + ASSERT_EQ(munmap(ptr, 10 * page_size), 0); +} + TEST_HARNESS_MAIN