On 12/07, Oleg Nesterov wrote: > > On 12/07, Jan Kratochvil wrote: > > > > On Mon, 07 Dec 2009 15:24:51 +0100, Oleg Nesterov wrote: > > > But. &raise_sigusr2 is not equal to the "actual" address of > > > &raise_sigusr2(), > > > this value points to the "thunk" (I do not know the correct English term) > > > > ppc64 calls it "function descriptor" (GDB > > ppc64_linux_convert_from_func_ptr_addr): > > For PPC64, a function descriptor is a TOC entry, > > Thanks Jan. > > > in a data section, > > Yes! > > Now I can't understand how this test-case could ever work on ppc. > step-jump-cont does: > > regs->nip = raise_sigusr2; <--- points to data section > ptrace(PTRACE_CONT); > > of course, the tracee gets SIGSEGV, this section is not executable.
Hmm. Looks like, "powerpc" means a lot of different hardware, and _PAGE_EXEC may be 0. I didn't notice this when I quickly grepped arch/powerpc/ IOW, perhaps on some machines r implies x ? Is yes, this can explain why the results differ on different machines. Oleg.
