Catch and recover from yet another linux kernel bug in mprotect.

[platform/upstream/libpciaccess.git] / src / linux_sysfs.c

diff --git a/src/linux_sysfs.c b/src/linux_sysfs.c
index 9e53fac..b1d196c 100644 (file)
--- a/src/linux_sysfs.c
+++ b/src/linux_sysfs.c
@@ -537,12 +537,11 @@ pci_device_linux_sysfs_map_range(struct pci_device *dev,
 
     map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
     if (map->memory == MAP_FAILED) {
-        err = errno;
         map->memory = NULL;
+       close(fd);
+       return errno;
     }
 
-    close(fd);
-
 #ifdef HAVE_MTRR
     if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
         sentry.type = MTRR_TYPE_WRBACK;
@@ -562,11 +561,27 @@ pci_device_linux_sysfs_map_range(struct pci_device *dev,
        }
        /* KLUDGE ALERT -- rewrite the PTEs to turn off the CD and WT bits */
        mprotect (map->memory, map->size, PROT_NONE);
-       mprotect (map->memory, map->size, PROT_READ|PROT_WRITE);
+       err = mprotect (map->memory, map->size, PROT_READ|PROT_WRITE);
+
+       if (err != 0) {
+           fprintf(stderr, "mprotect(PROT_READ | PROT_WRITE) failed: %s\n",
+                   strerror(errno));
+           fprintf(stderr, "remapping without mprotect performace kludge.\n");
+
+           munmap(map->memory, map->size);
+           map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
+           if (map->memory == MAP_FAILED) {
+               map->memory = NULL;
+               close(fd);
+               return errno;
+           }
+       }
     }
 #endif
 
-    return err;
+    close(fd);
+
+    return 0;
 }
 
 /**