Date: Sun, 23 Jul 2017 01:03:08 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 220930] DTrace, pid provider: Can't get a trace of a malloc function in google-perftools Message-ID: <bug-220930-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D220930 Bug ID: 220930 Summary: DTrace, pid provider: Can't get a trace of a malloc function in google-perftools Product: Base System Version: 11.0-STABLE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: misc Assignee: freebsd-bugs@FreeBSD.org Reporter: yuri@rawbw.com Created attachment 184607 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D184607&action= =3Dedit malloc-user-process.d Here's how to repeat: 1. Install qTox and google perftools: pkg install qTox google-perftools 2. Load dtraceall kernel module: kldload dtraceall.ko 3. Place the attached scripts 'start-process-and-wait' and 'malloc-user-process.d' into some directory and set +x flag on both. 4. As a regular user, start qTox in stopped mode: LD_PRELOAD=3D/usr/local/lib/libtcmalloc.so ./start-process-and-wait /usr/local/bin/qtox 5. As root, with the pid printed on step 4, start dtrace: ./malloc-user-process.d {pid} > out.log In many cases, step 5 prints one of these two error messages and exits: > dtrace: failed to compile script ./malloc-user-process.d: line 9: Invalid= argument or > dtrace: failed to compile script ./malloc-user-process.d: line 13: failed= to create return probe for 'malloc': Unknown variable name In both cases the debugged process gets continued. In rare other cases dtrace continues and eventually deadlocks: > dtrace: script './malloc-user-process.d' matched 2 probes - at this point qtox process stays in TX+ state, and dtrace stays in S+ sta= te forever. All errors are invalid. pidNNN argument should be valid in line 9, and mall= oc symbol is always present by the virtue of LD_PRELOAD of the library with 'malloc' symbol in it. dtrace shouldn't deadlock. Ctrl-C on dtrace doesn't stop it. However, 'kill= all -9 dtrace' does. --=20 You are receiving this mail because: You are the assignee for the bug.=
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