Allow the kcov buffer to be mmaped multiple times.

After r344391 this restriction is no longer needed. Sponsored by: DARPA, AFRL
stacktic · Feb 21, 2019 · 27723fd · 27723fd
1 parent ccea7c1
commit 27723fd
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Showing 2 changed files with 12 additions and 10 deletions.
diff --git a/sys/kern/kern_kcov.c b/sys/kern/kern_kcov.c
@@ -127,7 +127,6 @@ struct kcov_info {
 	size_t		bufsize;	/* (o) */
 	kcov_state_t	state;		/* (s) */
 	int		mode;		/* (l) */
-	bool		mmap;
 };
 
 /* Prototypes */
@@ -303,7 +302,6 @@ kcov_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
 	info->state = KCOV_STATE_OPEN;
 	info->thread = NULL;
 	info->mode = -1;
-	info->mmap = false;
 
 	if ((error = devfs_set_cdevpriv(info, kcov_mmap_cleanup)) != 0)
 		kcov_mmap_cleanup(info);
@@ -344,12 +342,10 @@ kcov_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
 	if ((error = devfs_get_cdevpriv((void **)&info)) != 0)
 		return (error);
 
-	if (info->kvaddr == 0 || size / KCOV_ELEMENT_SIZE != info->entries ||
-	    info->mmap != false)
+	if (info->kvaddr == 0 || size / KCOV_ELEMENT_SIZE != info->entries)
 		return (EINVAL);
 
 	vm_object_reference(info->bufobj);
-	info->mmap = true;
 	*offset = 0;
 	*object = info->bufobj;
 	return (0);

diff --git a/tests/sys/kern/kcov.c b/tests/sys/kern/kcov.c
@@ -80,7 +80,7 @@ ATF_TC_BODY(kcov_bufsize, tc)
 ATF_TC_WITHOUT_HEAD(kcov_mmap);
 ATF_TC_BODY(kcov_mmap, tc)
 {
-	void *data;
+	void *data1, *data2;
 	int fd;
 
 	fd = open_kcov();
@@ -95,12 +95,18 @@ ATF_TC_BODY(kcov_mmap, tc)
 	    fd, 0) == MAP_FAILED);
 	ATF_CHECK(mmap(NULL, 3 * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
 	    fd, 0) == MAP_FAILED);
-	ATF_REQUIRE((data = mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE,
+	ATF_REQUIRE((data1 = mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE,
 	    MAP_SHARED, fd, 0)) != MAP_FAILED);
-	ATF_CHECK(mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
-	    fd, 0) == MAP_FAILED);
+	ATF_REQUIRE((data2 = mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE,
+	    MAP_SHARED, fd, 0)) != MAP_FAILED);
+
+	*(uint64_t *)data1 = 0x123456789abcdeful;
+	ATF_REQUIRE(*(uint64_t *)data2 == 0x123456789abcdefull);
+	*(uint64_t *)data2 = 0xfedcba9876543210ul;
+	ATF_REQUIRE(*(uint64_t *)data1 == 0xfedcba9876543210ull);
 
-	munmap(data, 2 * PAGE_SIZE);
+	munmap(data1, 2 * PAGE_SIZE);
+	munmap(data2, 2 * PAGE_SIZE);
 
 	close(fd);
 }