Just using PHP7, I don't call opcache_reset()
after a while I get something like:

<b>Fatal error</b>:  require_once(): Failed opening required '/var/www/~users/alex/php7/omi-frame-2/src/controller/App.phpb_my
' (include_path='.:/opt/php-7.0.0/lib/php') in <b>/var/www/~users/alex/php7/omi-frame-2/src/init.php</b> on line <b>5</b><br />

It looks like the ending string mark is not copied 
I need to restart PHP-FPM 2 or 3 times per day

Thanks,
Alex

This bug is important, it breaks opcache until php-fpm gets a restart !!!

It looks like a very simple fix !!! Probably a bad memcopy there, it does not copy the ending \0 

Thanks

Can confirm: while this happens reliably with \opcache_reset(), we end up running into this issue after a couple of hours of regular use as well.

Updated bug summary

The same bug.
Ubuntu 14.04.3 LTS
PHP 7.0.1-dev (cli) (built: Oct 29 2015 10:15:42) ( NTS )

from PHP-7.0 branch

I spent some time today tracing this bug as it is preventing our migration to PHP 7.

The bug is caused by the opcache interned strings functionality. A simple workaround is to set

opcache.interned_strings_buffer = 0

in php.ini.

Looking at the code, I believe that the bug might be caused by this [0] call to memcpy(). Changing this to 

memcpy(ZSTR_VAL(p->key), ZSTR_VAL(str), ZSTR_LEN(str) + 1);

has made the issue go away. However I am not familiar enough with opcache to determine whether this is an acceptable change.

[0] http://lxr.php.net/xref/PHP_MASTER/ext/opcache/ZendAccelerator.c#374

I can confirm that workaround and proposed fix solve the issue for me.

It looks like the right solution - based on pattern elsewhere - but I'm not an expert either.

Hey Xinchen, can you confirm this fix is proper or clarify the behavior? Thanks

actually, it's intentional only copy Z_STRLEN, please verify this fix:

diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index eaadac6..18862b3 100644
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -249,24 +249,27 @@ static void accel_interned_strings_restore_state(void)
     uint nIndex;
     Bucket *p;

-	ZCSG(interned_strings_top) = ZCSG(interned_strings_saved_top);
-    while (idx > 0) {
-    	idx--;
-		p = ZCSG(interned_strings).arData + idx;
-		if ((char*)p->key < ZCSG(interned_strings_top)) break;
-		ZCSG(interned_strings).nNumUsed--;
-		ZCSG(interned_strings).nNumOfElements--;
-
-		nIndex = p->h | ZCSG(interned_strings).nTableMask;
-		if (HT_HASH(&ZCSG(interned_strings), nIndex) == HT_IDX_TO_HASH(idx)) {
-			HT_HASH(&ZCSG(interned_strings), nIndex) = Z_NEXT(p->val);
-		} else {
-			uint32_t prev = HT_HASH(&ZCSG(interned_strings), nIndex);
-			while (Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val) != idx) {
-				prev = Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val);
- 			}
-			Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val) = Z_NEXT(p->val);
- 		}
+	if (EXPECTED(ZCSG(interned_strings_top) > ZCSG(interned_strings_saved_top))) {
+		memset(ZCSG(interned_strings_saved_top),0, ZCSG(interned_strings_top) - ZCSG(interned_strings_saved_top));
+		ZCSG(interned_strings_top) = ZCSG(interned_strings_saved_top);
+		while (idx > 0) {
+			idx--;
+			p = ZCSG(interned_strings).arData + idx;
+			if ((char*)p->key < ZCSG(interned_strings_top)) break;
+			ZCSG(interned_strings).nNumUsed--;
+			ZCSG(interned_strings).nNumOfElements--;
+
+			nIndex = p->h | ZCSG(interned_strings).nTableMask;
+			if (HT_HASH(&ZCSG(interned_strings), nIndex) == HT_IDX_TO_HASH(idx)) {
+				HT_HASH(&ZCSG(interned_strings), nIndex) = Z_NEXT(p->val);
+			} else {
+				uint32_t prev = HT_HASH(&ZCSG(interned_strings), nIndex);
+				while (Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val) != idx) {
+					prev = Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val);
+				}
+				Z_NEXT(HT_HASH_TO_BUCKET(&ZCSG(interned_strings), prev)->val) = Z_NEXT(p->val);
+			}
+		}
 	}
 }

Applied patch and recompiled. The bug seems to be resolved.

Confirming that patch solves it for me too.