Hi! In the process of cleaning my work up, I've run into an odd problem which only shows up when I set the optimization level to -O2. At -O0, it's perfectly fine.
The issue is that somehow execution ends up at address 0x0. This likely happens due to a _CPU_Context_switch, where the rsp is set to a corrupted value, leading to a corrupt (i.e. 0) return address at the end of the context switch. What's curious is that this corruption _seems_ to occur in _ISR_Handler's call to _Thread_Dispatch, by somehow messing the value of rsp up - I honestly don't know this for sure because gdb says one thing (i.e. that rsp = 0), but setting up some code (cmpq $0, rsp) to check this seems to say rsp is non-zero, at least. This is an odd heisenbug I'd like to investigate for sure - I just thought I'd shoot this email out because: - If I can't figure it out tomorrow, soon, I'll just drop it so I can create more logical commits to send as patches upstream (thereby leaving -O0 upstream, at least temporarily) - If anyone's seen an odd stack corruption like this, or has any advice on debugging it, could you let me know? I suspect something like interrupting tasks which ought not to be interrupted (perhaps I forgot to implement some kind of "CPU_ISR_Disable") - is there anything you can think of of that sort? Also, here's a Github PR like last time with all the work (just for the overall changes, not the specific commits!). I'd appreciate a quick review if anyone could - sorry about sending this out over the weekend! I've had a surprising share of Heisenbugs with QEMU in the past week. https://github.com/AmaanC/rtems-gsoc18/pull/3/files _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel