Re: MALLOC_PERTURB_: everyone should set this envvar
Jim Meyering (j...@meyering.net) said: I posted about MALLOC_PERTURB_ about a year ago, http://thread.gmane.org/gmane.linux.redhat.fedora.devel/132690 but it is clear that not everyone is setting the variable, so for those who didn't take the time last year, or who are new to the subject, do yourself a favor and set MALLOC_PERTURB_ to a value in 1..255 everywhere. See the 'debugmode' package. Bill -- devel mailing list devel@lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/devel
Re: MALLOC_PERTURB_: everyone should set this envvar
# http://udrepper.livejournal.com/11429.html export MALLOC_PERTURB_=$(($RANDOM % 255 + 1)) For supportability (and to help remind you to turn it off before performance tests), then also consider adding a line such as: echo 12 MALLOC_PERTURB_=$MALLOC_PERTURB_ # $HOME/.bash_profile Also inexpensive: export MALLOC_CHECK_=1 # 0: off; 1: announce on stderr; 2: abort echo 12 MALLOC_CHECK_=$MALLOC_CHECK_ # $HOME/.bash_profile which handles double free(), single-byte overruns, etc. For always on detection of overlapping memcpy() at low cost, then consider http://bitwagon.com/glibc-memlap/glibc-memlap.html . -- -- devel mailing list devel@lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/devel
Re: MALLOC_PERTURB_: everyone should set this envvar
John Reiser wrote: # http://udrepper.livejournal.com/11429.html export MALLOC_PERTURB_=$(($RANDOM % 255 + 1)) For supportability (and to help remind you to turn it off before performance tests), then also consider adding a line such as: echo 12 MALLOC_PERTURB_=$MALLOC_PERTURB_ # $HOME/.bash_profile Good idea. Or have a weekly cron job send clue-bat mail to yourself reminding you that you do have this envvar set. For the first year or so during which I had this enabled, when I'd hit a memory-related problem, I didn't immediately think, Oh! that may be because I've enabled MALLOC_PERTURB_, so the above might well help, initially. If you do add something like that, be sure to use a guard so that it is printed only for interactive sessions, e.g., test -n $PS1 echo 12 MALLOC_PERTURB_=$MALLOC_PERTURB_ Once you've been graced with enough MALLOC_PERTURB_-induced failures, you get used to it, always remember to include it in bug reports,... then you can turn that off ;-) -- devel mailing list devel@lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/devel
