On Thu, Feb 19, 2009 at 3:45 AM, Mattias Engdegård <[email protected]> wrote: > msync(2) does not protect against reading from mapped but > read-protected addresses (MAP_NONE), which are not uncommon on x86_64. > We recently had a number of crashes resulting from this (although > libunwind was not directly involved in this case).
Yes - I've seen this particular crash before. But it seems to be relatively uncommon and most of the bad references were due to issues that could be handled in libunwind. Due to the patches that went in during the last year or so, I think many of those cases are resolved. Remaining x86_64 issues have to do with: * Compiler generating incomplete unwind info * Occasional patches that introduce calls to malloc Will also benchmark pread(). We have code that's sensitive to unwind performance. So we tend to use a small (but potentially racy) cache to avoid getting into the kernel often. -Arun _______________________________________________ Libunwind-devel mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/libunwind-devel
