Hi Dmitry, I will try and get something to you tomorrow. Just wondering, but what happens to the old struct kcov if a task opens /sys/kernel/debug/kcov twice? I am looking here https://elixir.free-electrons.com/linux/v4.15-rc8/source/kernel/kcov.c#L381 and I don't see where the previous struct would get freed.
Regards, Shankara On Sat, Jan 20, 2018 at 4:38 AM, Dmitry Vyukov <dvyu...@google.com> wrote: > On Fri, Jan 19, 2018 at 8:29 PM, Shankara Pailoor <sp3...@columbia.edu> wrote: >> Hi Dmitry, >> >> I added support for kcov in strace and I have been tracing a fairly >> large program but after a little while, I notice that when I mmap a >> new cover buffer, the call fails with ENOMEM. After killing the >> program, I try and rerun and I notice that there is nearly no memory >> on the system. When I do a kmemleak scan I get the following reports: >> >> I believe the problem occurs when I try and setup the kcov buffer >> again after an exec. Instead of reusing the old file descriptor I open >> kcov again within that process. In that case, I don't know what >> happens to the old kcov struct. >> >> I don't see a maintainers list for kcov so I decided to email you >> directly. Let me know what more information I can provide. > > > Hi Shankara, > > Looks bad. Can you provide a reproducer? > We extensively use kcov with syzkaller, but have not observed such > leaks. Also I don't see anything obvious in the code. > > Thanks
