http://4e.iwp9.org
4th iwp9
October 21-23 2009
i was trying to use 8l's '-e' flag today, when i found some
interesting problems.
first, -e doesn't do what it says unless you pass -p, which goes
unmentioned in the manual page. (luckily i read the source).
second, and more importantly, the calls to _tracein/_traceout are
skipped, as in the
you can see there is a JMP over _tracein and a RET before _traceout.
what gives?
ah, that's the magic! the idea is to be able to enable and disable these
tracepoints
at runtime in a multiprocessor environment without any locking.
- erik
On Tue, May 27, 2014 at 04:16:24PM -0400, erik quanstrom wrote:
you can see there is a JMP over _tracein and a RET before _traceout.
what gives?
ah, that's the magic! the idea is to be able to enable and disable these
tracepoints
at runtime in a multiprocessor environment without any
ok. i'm beginning to understand better. is there a specific use case,
such as the kernel or userland?
i didn't see anything like a tool that could poke nops into the right
places. i started to write an acid function to put the nops in one
named function, and then i realized that the ret
