Date: Sun, 29 May 2011 18:10:06 GMT From: dfilter@FreeBSD.ORG (dfilter service) To: freebsd-bugs@FreeBSD.org Subject: Re: kern/154504: commit references a PR Message-ID: <201105291810.p4TIA6IS081905@freefall.freebsd.org>
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The following reply was made to PR kern/154504; it has been noted by GNATS. From: dfilter@FreeBSD.ORG (dfilter service) To: bug-followup@FreeBSD.org Cc: Subject: Re: kern/154504: commit references a PR Date: Sun, 29 May 2011 18:01:06 +0000 (UTC) Author: trociny Date: Sun May 29 18:00:50 2011 New Revision: 222454 URL: http://svn.freebsd.org/changeset/base/222454 Log: In soreceive_generic(), if MSG_WAITALL is set but the request is larger than the receive buffer, we have to receive in sections. When notifying the protocol that some data has been drained the lock is released for a moment. Returning we block waiting for the rest of data. There is a race, when data could arrive while the lock was released and then the connection stalls in sbwait. Fix this by checking for data before blocking and skip blocking if there are some. PR: kern/154504 Reported by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua> Tested by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua> Reviewed by: rwatson Approved by: kib (co-mentor) MFC after: 2 weeks Modified: head/sys/kern/uipc_socket.c Modified: head/sys/kern/uipc_socket.c ============================================================================== --- head/sys/kern/uipc_socket.c Sun May 29 15:10:12 2011 (r222453) +++ head/sys/kern/uipc_socket.c Sun May 29 18:00:50 2011 (r222454) @@ -1845,10 +1845,16 @@ dontblock: } SBLASTRECORDCHK(&so->so_rcv); SBLASTMBUFCHK(&so->so_rcv); - error = sbwait(&so->so_rcv); - if (error) { - SOCKBUF_UNLOCK(&so->so_rcv); - goto release; + /* + * We could receive some data while was notifying + * the protocol. Skip blocking in this case. + */ + if (so->so_rcv.sb_mb == NULL) { + error = sbwait(&so->so_rcv); + if (error) { + SOCKBUF_UNLOCK(&so->so_rcv); + goto release; + } } m = so->so_rcv.sb_mb; if (m != NULL) _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
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