On Wed, Dec 12, 2018 at 6:29 AM Nick Clifton <ni...@redhat.com> wrote: > > Sorry to bother you, but I have another libiberty demangler resource > exhaustion prevention patch to present. This one is for: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87241 > > Jonathan Wakely reported that __cxa_demanlge() was returning a -2 > result, but I did not see this. Instead I found that > consume_count_with_underscores() is returning a very large number > (because a very large value is encoded in the mangled string) and this > is resulting in many calls to remember_Ktype() which eventually > exhaust the amount of memory available. > > The attached patch is a simplistic approach to solving this problem by > adding a hard upper limit on the number of qualifiers that will be > allowed by the demangler. I am not sure if this is the best approach > to solving the problem, but it is a simple one, and I would think one > that would not prevent the demangling of any real mangled names. The > limit does not have to be DEMANGLE_RECURSE_LIMIT of course. I just > chose that value because it was convenient and of a size that I > thought was appropriate. > > I also did run the libiberty testsuite this time, with no failures > reported. :-) > > OK to apply ? > > Cheers > Nick > > libiberty/ChangeLog > 2018-12-12 Nick Clifton <ni...@redhat.com> > > * cplus-dem.c (demangle_qualified): Add an upper limit on the > number of qualifiers supported, based upon the value of > DEMANGLE_RECURSE_LIMIT.
This issue also will be resolved by disabling or removing the old demangling code, which I haven't seen anyone argue against. Jason
