* Luke Diamand via Elfutils-devel: > I've got a few cores where report_r_debug() in link_map.c fails to > find all of the modules - for example I had libc.so missing. This > obviously meant that elfutils could not backtrace my core. > > It seems to be related to this code: > > /* There can't be more elements in the link_map list than there are > segments. DWFL->lookup_elts is probably twice that number, so it > is certainly above the upper bound. If we iterate too many times, > there must be a loop in the pointers due to link_map clobberation. */ > size_t iterations = 0; > > while (next != 0 && ++iterations < dwfl->lookup_elts) > > I've changed this to just keep going until it reaches > dwfl->lookup_elts*5, which seems to "fix" it, but I feel there must be > a better fix! > > The most recent core I saw with this had lookup_elts=36, and hit 109 > iterations of the loop and then backtraced just fine.
It's probably another fallout from -z separate-code, which tends to create four LOAD segments. The magic number 5 sounds about right, as gold also has -z text-unlikely-segment, which might result in creating that number of load segments (but I haven't tried). Thanks, Florian
