>Number:         159352
>Category:       bin
>Synopsis:       accidental busy-waiting loop in fetch(3)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Aug 01 12:10:05 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Mathieu
>Release:        8.2-STABLE
>Organization:
>Environment:
8.2-STABLE FreeBSD 8.2-STABLE #0 r223938M
>Description:
Sometimes, fetch(1) will use 100% CPU time while downloading.  There's a loop 
that will retry I/O syscalls that returned EAGAIN immediately without blocking 
due to a small bug.

>How-To-Repeat:
Probably only noticeable on slow links.

>Fix:
Index: common.c
===================================================================
--- common.c    (revision 223938)
+++ common.c    (working copy)
@@ -429,12 +429,6 @@
        ssize_t rlen, total;
        int r;
 
-       if (fetchTimeout) {
-               FD_ZERO(&readfds);
-               gettimeofday(&timeout, NULL);
-               timeout.tv_sec += fetchTimeout;
-       }
-
        total = 0;
        while (len > 0) {
                /*
@@ -474,6 +468,11 @@
                        return (-1);
                }
                // assert(rlen == FETCH_READ_WAIT);
+               if (fetchTimeout) {
+                       FD_ZERO(&readfds);
+                       gettimeofday(&timeout, NULL);
+                       timeout.tv_sec += fetchTimeout;
+               }
                while (fetchTimeout && !FD_ISSET(conn->sd, &readfds)) {
                        FD_SET(conn->sd, &readfds);
                        gettimeofday(&now, NULL);
@@ -576,14 +575,13 @@
        ssize_t wlen, total;
        int r;
 
-       if (fetchTimeout) {
-               FD_ZERO(&writefds);
-               gettimeofday(&timeout, NULL);
-               timeout.tv_sec += fetchTimeout;
-       }
-
        total = 0;
        while (iovcnt > 0) {
+               if (fetchTimeout) {
+                       FD_ZERO(&writefds);
+                       gettimeofday(&timeout, NULL);
+                       timeout.tv_sec += fetchTimeout;
+               }
                while (fetchTimeout && !FD_ISSET(conn->sd, &writefds)) {
                        FD_SET(conn->sd, &writefds);
                        gettimeofday(&now, NULL);


>Release-Note:
>Audit-Trail:
>Unformatted:
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