Protect rx_call iovq from simultaneous attempts to empty it

The iovq queue is not safe to clear without holding the call lock.

FIXES 125110

LICENSE BSD

Reviewed-on: http://gerrit.openafs.org/242
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Hans-Werner Paulsen <hans@MPA-Garching.MPG.DE>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>

diff --git a/src/rx/rx_rdwr.c b/src/rx/rx_rdwr.c
index 61f6b2aa24a43e49276f4b5e3b46797cacbd92b6..c63dc09b20b2fa348feb75cbcf2f3f4bde5f298d 100644 (file)
--- a/src/rx/rx_rdwr.c
+++ b/src/rx/rx_rdwr.c
@@ -313,19 +313,17 @@ rx_ReadProc(struct rx_call *call, char *buf, int nbytes)
     char *tcurpos;
     SPLVAR;
 
-    /*
-     * Free any packets from the last call to ReadvProc/WritevProc.
-     * We do not need the lock because the receiver threads only
-     * touch the iovq when the RX_CALL_IOVEC_WAIT flag is set, and the
-     * RX_CALL_IOVEC_WAIT is always cleared before returning from
-     * ReadvProc/WritevProc.
-     */
+    /* Free any packets from the last call to ReadvProc/WritevProc */
+    NETPRI;
+    MUTEX_ENTER(&call->lock);
     if (!queue_IsEmpty(&call->iovq)) {
 #ifdef RXDEBUG_PACKET
         call->iovqc -=
 #endif /* RXDEBUG_PACKET */
             rxi_FreePackets(0, &call->iovq);
     }
+    MUTEX_EXIT(&call->lock);
+    USERPRI;
 
     /*
      * Most common case, all of the data is in the current iovec.
@@ -373,19 +371,17 @@ rx_ReadProc32(struct rx_call *call, afs_int32 * value)
     char *tcurpos;
     SPLVAR;
 
-    /*
-     * Free any packets from the last call to ReadvProc/WritevProc.
-     * We do not need the lock because the receiver threads only
-     * touch the iovq when the RX_CALL_IOVEC_WAIT flag is set, and the
-     * RX_CALL_IOVEC_WAIT is always cleared before returning from
-     * ReadvProc/WritevProc.
-     */
+    /* Free any packets from the last call to ReadvProc/WritevProc */
+    NETPRI;
+    MUTEX_ENTER(&call->lock);
     if (!queue_IsEmpty(&call->iovq)) {
 #ifdef RXDEBUG_PACKET
         call->iovqc -=
 #endif /* RXDEBUG_PACKET */
             rxi_FreePackets(0, &call->iovq);
     }
+    MUTEX_EXIT(&call->lock);
+    USERPRI;
 
     /*
      * Most common case, all of the data is in the current iovec.
@@ -880,19 +876,17 @@ rx_WriteProc(struct rx_call *call, char *buf, int nbytes)
     char *tcurpos;
     SPLVAR;
 
-    /*
-     * Free any packets from the last call to ReadvProc/WritevProc.
-     * We do not need the lock because the receiver threads only
-     * touch the iovq when the RX_CALL_IOVEC_WAIT flag is set, and the
-     * RX_CALL_IOVEC_WAIT is always cleared before returning from
-     * ReadvProc/WritevProc.
-     */
+    /* Free any packets from the last call to ReadvProc/WritevProc */
+    NETPRI;
+    MUTEX_ENTER(&call->lock);
     if (queue_IsNotEmpty(&call->iovq)) {
 #ifdef RXDEBUG_PACKET
         call->iovqc -=
 #endif /* RXDEBUG_PACKET */
             rxi_FreePackets(0, &call->iovq);
     }
+    MUTEX_EXIT(&call->lock);
+    USERPRI;
 
     /*
      * Most common case: all of the data fits in the current iovec.
@@ -930,19 +924,17 @@ rx_WriteProc32(struct rx_call *call, afs_int32 * value)
     char *tcurpos;
     SPLVAR;
 
-    /*
-     * Free any packets from the last call to ReadvProc/WritevProc.
-     * We do not need the lock because the receiver threads only
-     * touch the iovq when the RX_CALL_IOVEC_WAIT flag is set, and the
-     * RX_CALL_IOVEC_WAIT is always cleared before returning from
-     * ReadvProc/WritevProc.
-     */
+    /* Free any packets from the last call to ReadvProc/WritevProc */
+    NETPRI;
+    MUTEX_ENTER(&call->lock);
     if (queue_IsNotEmpty(&call->iovq)) {
 #ifdef RXDEBUG_PACKET
         call->iovqc -=
 #endif /* RXDEBUG_PACKET */
             rxi_FreePackets(0, &call->iovq);
     }
+    MUTEX_EXIT(&call->lock);
+    USERPRI;
 
     /*
      * Most common case: all of the data fits in the current iovec.