Re: [Valgrind-users] Enabling instrumentation with callgrind_control not working

[Christian P. <chr...@gm...>]

2015-02-02 10:42 GMT+00:00 Josef Weidendorfer <Jos...@gm...>:

> Am 02.02.2015 um 00:00 schrieb Christian Priebe:
> > I'm back to the previous issue that callgrind_control or more
> > specifically vgdb hangs. This is the output I get when running vgdb -d
> > ...
>
> Hmm. Then it looks like a hang in the vgdb handler in callgrind, but I
> have no idea why.
>
> Can you first check if the hang also appears with another callgrind
> request such as
> "vgdb --pid=XXX zero", and with another tool (e.g. none) and another vgdb
> request, like "vgdb --pid=XXX v.wait 500" ?
>
>
Ok, two observations regarding the zero and instrumentation requests. First
of all, the vgdb --pid=XXX zero request behaves the same as the ...
instrumentation on request. Second, I occasionally get a different debug
output from vgdb which looks like the following:

1422876588.712688 vgdb: using
/tmp/vgdb-pipe-from-vgdb-to-1800-by-root-on-???
/tmp/vgdb-pipe-to-vgdb-from-1800-by-root-on-???
/tmp/vgdb-pipe-shared-mem-vgdb-1800-by-root-on-???
1422876588.712838 opening /tmp/vgdb-pipe-from-vgdb-to-1800-by-root-on-???
write to pid
1422876588.712882 opened /tmp/vgdb-pipe-from-vgdb-to-1800-by-root-on-???
write to pid fd 4
1422876588.712915 writing write \003 to wake up len 1  notify: 1
1422876588.712998 opening /tmp/vgdb-pipe-to-vgdb-from-1800-by-root-on-???
read cmd result from pid
1422876588.712916 written_by_vgdb_before_sleep 0
seen_by_valgrind_before_sleep 0
1422876588.815261 written_by_vgdb_before_sleep 1
seen_by_valgrind_before_sleep 0
1422876588.917737 written_by_vgdb_before_sleep 1
seen_by_valgrind_before_sleep 1
1422876589.020165 written_by_vgdb_before_sleep 1
seen_by_valgrind_before_sleep 1
1422876589.120366 written_by_vgdb_before_sleep 1
seen_by_valgrind_before_sleep 1
...

The same line repeats until I shutdown vgdb. Ok, running "vgdb --pid=XXX
v.wait 500" without any tool (i.e. "valgrind bin/mysqld") results in the
same output as before:

...
1422877084.623194 getregs regs_bsz 216
1422877084.623215 getregs PTRACE_GETREGS
1422877084.623229 detected a working PTRACE_GETREGS
1422877084.623238 push bad_return return address ptrace_write_memory
1422877084.623248 Writing 0000000000000000 to 0x804792d18
1422877084.623329 setregs regs_bsz 216
1422877084.623338 setregs PTRACE_SETREGS
1422877084.623352 PTRACE_CONT to invoke
1422877084.623827 waitstopped waitpid status after PTRACE_CONT to invoke
before waitpid signal_expected 19


So, apparently this has nothing to do with callgrind but with valgrind (or
my setup) in general.


Thanks again,
Christian



> If that works, it would be interesting to see the last lines of
> Callgrind debug output
> with "... --ct-verbose=2 ..." (or 3...), but warning: this can be huge,
> and should be
> directed to a file (eg. with --log-file=XX).
>