Date: Wed, 13 Oct 2004 21:38:55 +0400 (MSD) From: Oleg Koreshkov <okor@NONEXISTENT.zone.salut.ru> To: FreeBSD-gnats-submit@FreeBSD.org Cc: yar@FreeBSD.org Subject: bin/72649: ftpd process can hang with high cpu load Message-ID: <200410131738.i9DHctAx090236@ns.salut.ru> Resent-Message-ID: <200410131740.i9DHePQw037564@freefall.freebsd.org>
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>Number: 72649
>Category: bin
>Synopsis: ftpd process can hang with high cpu load
>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: Wed Oct 13 17:40:24 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator: Oleg Koreshkov (okor (AT) zone.salut.ru)
>Release: FreeBSD 4.10-RELEASE-p2 i386 (CURRENT has the same bug)
>Organization:
none
>Environment:
FreeBSD 4.10
>Description:
ftpd process can consume 100% CPU doing nothing, looping endless loop,
if transferd file was overwritten during transfer.
If client of this session hangs, this ftpd process can live quite a
long time (2 hours or even more).
>How-To-Repeat:
Start transfer (TYPE I) of big file or delay transfer by ipfw pipe.
In another ftp session overwrite this file with smaller size (size must be > 0).
First ftpd process gets in to endless loop.
>Fix:
--- ftpd.c
+++ ftpd.c
@@ -2034,6 +2034,22 @@
goto data_err;
}
+
+ /*
+ * sendfile(2) can return zero bytes written
+ * (cnt == 0), without indicating error,
+ * when file was truncated (by another process)
+ * during transfer.
+ * We consider this case as temporary error,
+ * however it possible to treat it
+ * as successful transfer completion.
+ */
+ if (cnt == 0) {
+ transflag = 0;
+ reply(450, "File was overwritten "
+ "during transfer.");
+ return (-1);
+ }
}
transflag = 0;
>Release-Note:
>Audit-Trail:
>Unformatted:
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