On 02/13/2012 04:09 PM, Uros Bizjak wrote: > On Mon, Feb 13, 2012 at 11:57 PM, Richard Henderson <r...@redhat.com> wrote: >> On 02/13/2012 02:54 PM, Uros Bizjak wrote: >>> - movq 56(%rsi), %rdx >>> movl %edi, %eax >>> cfi_def_cfa(%rcx, 0) >>> - cfi_register(%rip, %rdx) >>> movq %rcx, %rsp >>> - jmp *%rdx >>> + jmp *56(%rsi) >> >> If you're going to do that, the correct fix for the unwind info is >> >> - cfi_register(%rip, %rdx) >> + cfi_offset(%rip, 56) > > Hm, we just defined new CFA as rcx+0, so we should define location of > rip relative to new CFA. Since CFA points to stack slot just before > return address was pushed, new rip lies at CFA-8 for 64bit resp. CFA-4 > for x86_32. Did I get these .cfi directives correctly?
No. The value at %rcx-8 is total garbage. There no guarantee that the call stack leading to this abort has anything in common with the call stack that created the jmpbuf, except *above* %rcx, the new CFA. The new rip is at rsi+56. You can see that in that you jump to it. r~
