Date: Sat, 23 Jun 2012 15:21:12 GMT From: "W.L. Tai" <t10661789@yahoo.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/169350: Extraneous output when tracing writes with output redirect to a file Message-ID: <201206231521.q5NFLCJx051989@red.freebsd.org> Resent-Message-ID: <201206231530.q5NFUA7i009993@freefall.freebsd.org>
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>Number: 169350 >Category: kern >Synopsis: Extraneous output when tracing writes with output redirect to a file >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: Sat Jun 23 15:30:10 UTC 2012 >Closed-Date: >Last-Modified: >Originator: W.L. Tai >Release: 9.0 stable >Organization: >Environment: FreeBSD aaa.local 9.0-STABLE FreeBSD 9.0-STABLE #0: Fri Jun 22 20:51:15 HKT 2012 root@aaa.local:/usr/obj/usr/src/sys/TAI amd64 >Description: Extraneous output when tracing writes from entry to return with output redirection to a file. >How-To-Repeat: Consider the following script: test-bug.d #!/usr/sbin/dtrace -s #pragma D option quiet vfs::vop_read:entry, vfs::vop_write:entry /execname != "dtrace"/ { self->flag = 1; } vfs::vop_read:return, vfs::vop_write:return /self->flag/ { this->flag = 1; self->flag = 0; } vfs::vop_read:return, vfs::vop_write:return /this->flag/ { printf("%s\n", execname); } After running dtrace -s test-bug.d -n 'tick-5s { exit(0); }' > /tmp/test the file /tmp/test would contains lines with dtrace, which should not be there. Somehow dtrace has inherit the value of this->flag. >Fix: Work around: Either continue to use self->flag or use the predicate /this->flag && execname != "dtrace"/ >Release-Note: >Audit-Trail: >Unformatted:
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