1 files changed, 32 insertions, 3 deletions

diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index 05654f5e48d5..c4d6d2e20e0d 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -32,6 +32,8 @@
 #include <assert.h>
 #include <ftw.h>
 #include <time.h>
+#include <setjmp.h>
+#include <signal.h>
 #include <sys/types.h>
 #include <sys/errno.h>
 #include <sys/fcntl.h>
@@ -824,21 +826,38 @@ static void show_file(const char *name, const struct stat *st)
                         atime, now - st->st_atime);
 }
 
+static sigjmp_buf sigbus_jmp;
+
+static void * volatile sigbus_addr;
+
+static void sigbus_handler(int sig, siginfo_t *info, void *ucontex)
+{
+        (void)sig;
+        (void)ucontex;
+        sigbus_addr = info ? info->si_addr : NULL;
+        siglongjmp(sigbus_jmp, 1);
+}
+
+static struct sigaction sigbus_action = {
+        .sa_sigaction = sigbus_handler,
+        .sa_flags = SA_SIGINFO,
+};
+
 static void walk_file(const char *name, const struct stat *st)
 {
         uint8_t vec[PAGEMAP_BATCH];
         uint64_t buf[PAGEMAP_BATCH], flags;
         unsigned long nr_pages, pfn, i;
+        off_t off, end = st->st_size;
         int fd;
-        off_t off;
         ssize_t len;
         void *ptr;
         int first = 1;
 
         fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);
 
-        for (off = 0; off < st->st_size; off += len) {
-                nr_pages = (st->st_size - off + page_size - 1) / page_size;
+        for (off = 0; off < end; off += len) {
+                nr_pages = (end - off + page_size - 1) / page_size;
                 if (nr_pages > PAGEMAP_BATCH)
                         nr_pages = PAGEMAP_BATCH;
                 len = nr_pages * page_size;
@@ -855,11 +874,19 @@ static void walk_file(const char *name, const struct stat *st)
                 if (madvise(ptr, len, MADV_RANDOM))
                         fatal("madvice failed: %s", name);
 
+                if (sigsetjmp(sigbus_jmp, 1)) {
+                        end = off + sigbus_addr ? sigbus_addr - ptr : 0;
+                        fprintf(stderr, "got sigbus at offset %lld: %s\n",
+                                        (long long)end, name);
+                        goto got_sigbus;
+                }
+
                 /* populate ptes */
                 for (i = 0; i < nr_pages ; i++) {
                         if (vec[i] & 1)
                                 (void)*(volatile int *)(ptr + i * page_size);
                 }
+got_sigbus:
 
                 /* turn off harvesting reference bits */
                 if (madvise(ptr, len, MADV_SEQUENTIAL))
@@ -910,6 +937,7 @@ static void walk_page_cache(void)
 
         kpageflags_fd = checked_open(PROC_KPAGEFLAGS, O_RDONLY);
         pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
+        sigaction(SIGBUS, &sigbus_action, NULL);
 
         if (stat(opt_file, &st))
                 fatal("stat failed: %s\n", opt_file);
@@ -925,6 +953,7 @@ static void walk_page_cache(void)
 
         close(kpageflags_fd);
         close(pagemap_fd);
+        signal(SIGBUS, SIG_DFL);
 }
 
 static void parse_file(const char *name)