Launchpad has imported 1 comments from the remote bug at http://sourceware.org/bugzilla/show_bug.cgi?id=16629.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2014-02-24T03:09:25+00:00 Michael Hudson-Doyle wrote: Created attachment 7435 adapted from example in http://pubs.opengroup.org/onlinepubs/009695399/functions/makecontext.html I'm attaching a simple demo program for makecontext/swapcontext that I found somewhere with the addition of code to print the alternate signal stack before and after calling swapcontext. On aarch64 it prints this: start f2 start f1 finish f2 finish f1 {ss_sp: (nil), ss_flags: 2, ss_size: 0} {ss_sp: 0x7ffbe931f8, ss_flags: 0, ss_size: 8192} It turns out that because setcontext is implemented in terms of the rt_sigreturn syscall it ends up copying the uc_stack data from the passed context into the (kernel) task's sigaltstack parameters. Hilarity ensues. Specifically it means that programs linked against the gccgo runtime sometimes handle signals with SP pointing at memory that another thread is using for its stack, with predictably bad results. Reply at: https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1279620/comments/5 ** Changed in: eglibc Status: Unknown => Confirmed ** Changed in: eglibc Importance: Unknown => Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1279620 Title: stack corruption running "go install launchpad.net/juju-core/..." To manage notifications about this bug go to: https://bugs.launchpad.net/eglibc/+bug/1279620/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
