On 26/04/24 12:02AM, Suren Baghdasaryan wrote: > When running tearing tests we need to ensure the pages we use include > VMAs that were mapped by the child process for this test. Currently we > always use the first two pages, checking VMAs at their boundaries and > this works, however once we add tests for /proc/pid/smaps, the first two > pages might not contain the VMAs that child modifies. > Locate the page that contains the first VMA mapped by the child and use > that and the next page for the test. > > Signed-off-by: Suren Baghdasaryan <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]> > --- > tools/testing/selftests/proc/proc-maps-race.c | 78 ++++++++++++++++--- > 1 file changed, 68 insertions(+), 10 deletions(-) > > diff --git a/tools/testing/selftests/proc/proc-maps-race.c > b/tools/testing/selftests/proc/proc-maps-race.c > index a734553718da..c5031b0593b7 100644 > --- a/tools/testing/selftests/proc/proc-maps-race.c > +++ b/tools/testing/selftests/proc/proc-maps-race.c > @@ -39,6 +39,13 @@ > #include <sys/types.h> > #include <sys/wait.h> > > +#define min(a, b) \ > + ({ \ > + typeof(a) _a = (a); \ > + typeof(b) _b = (b); \ > + _a < _b ? _a : _b; \ > + }) > + Another implementation of min in the selftests. I guess it's somewhat unavoidable. > /* /proc/pid/maps parsing routines */ > struct page_content { > char *data; > @@ -77,6 +84,7 @@ FIXTURE(proc_maps_race) > struct line_content first_line; > unsigned long duration_sec; > int shared_mem_size; > + int skip_pages; > int page_size; > int vma_count; > bool verbose; > @@ -105,27 +113,68 @@ struct vma_modifier_info { > void *child_mapped_addr[]; > }; > > - > -static bool read_two_pages(FIXTURE_DATA(proc_maps_race) *self) > +static bool read_page(FIXTURE_DATA(proc_maps_race) *self, > + struct page_content *page) > { > ssize_t bytes_read; > > - if (lseek(self->maps_fd, 0, SEEK_SET) < 0) > + bytes_read = read(self->maps_fd, page->data, self->page_size); > + if (bytes_read <= 0) > return false; > > - bytes_read = read(self->maps_fd, self->page1.data, self->page_size); > - if (bytes_read <= 0) > + /* Make sure data always ends with a newline character. */ > + if (page->data[bytes_read - 1] != '\n') > return false; > > - self->page1.size = bytes_read; > + page->size = bytes_read; > > - bytes_read = read(self->maps_fd, self->page2.data, self->page_size); > - if (bytes_read <= 0) > + return true; > +} > + > +static int locate_containing_page(FIXTURE_DATA(proc_maps_race) *self, > + unsigned long addr, unsigned long size) > +{ > + unsigned long start, end; > + int page = 0; > + > + if (lseek(self->maps_fd, 0, SEEK_SET) < 0) > + return -1; > + > + while (true) { > + char *curr_pos; > + char *end_pos; > + > + if (!read_page(self, &self->page1)) > + return -1; > + > + curr_pos = self->page1.data; > + end_pos = self->page1.data + self->page1.size; > + while (curr_pos < end_pos) { > + if (sscanf(curr_pos, "%lx-%lx", &start, &end) == 2 && > + start == addr && end == addr + size) > + return page; > + > + curr_pos = strchr(curr_pos, '\n'); > + if (!curr_pos) > + break; > + curr_pos++; > + } > + page++; > + } > + > + return 0; > +} > + > +static bool read_two_pages(FIXTURE_DATA(proc_maps_race) *self) > +{ > + if (lseek(self->maps_fd, 0, SEEK_SET) < 0) > return false; > > - self->page2.size = bytes_read; > + for (int i = 0; i < self->skip_pages; i++) > + if (!read_page(self, &self->page1)) > + return false; > > - return true; > + return read_page(self, &self->page1) && read_page(self, &self->page2); > } > > static void copy_first_line(struct page_content *page, char *first_line) > @@ -418,6 +467,8 @@ FIXTURE_SETUP(proc_maps_race) > struct vma_modifier_info *mod_info; > pthread_mutexattr_t mutex_attr; > pthread_condattr_t cond_attr; > + unsigned long first_map_addr; > + unsigned long last_map_addr; > unsigned long duration_sec; > char fname[32]; > > @@ -502,6 +553,13 @@ FIXTURE_SETUP(proc_maps_race) > self->page2.data = malloc(self->page_size); > ASSERT_NE(self->page2.data, NULL); > > + first_map_addr = (unsigned long)mod_info->child_mapped_addr[0]; > + last_map_addr = (unsigned > long)mod_info->child_mapped_addr[mod_info->vma_count - 1]; > + > + self->skip_pages = locate_containing_page(self, > + min(first_map_addr, last_map_addr), > + self->page_size * 3); > + ASSERT_NE(self->skip_pages, -1); > ASSERT_TRUE(read_boundary_lines(self, &self->last_line, > &self->first_line)); > > /* > -- > 2.54.0.545.g6539524ca2-goog >
