Messages in this thread | | | Date | Wed, 5 Dec 2012 10:29:51 +0100 | From | Jan Kratochvil <> | Subject | Re: PTRACE_SYSCALL && vsyscall (Was: arch_check_bp_in_kernelspace: fix the range check) |
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On Sun, 02 Dec 2012 20:30:58 +0100, Oleg Nesterov wrote: > Yes, that is why I said this needs the new option.
I do not mind new options although personally I do not find them meaningful for an already deprecated ABI compatibility-only issue.
> If the tracer does PTRACE_SYSCALL the tracee reports syscall exit > _after_ gettimeofday/etc. The tracer can look at regs->orig_ax == -1 > and detect that this is not syscall but vsyscall, it can look at > regs->ip then (not with the patch below).
I believe applications just call PTRACE_SYSCALL twice, without checking orig_eax. At least strace and its TCB_INSYSCALL looks so.
On Mon, 03 Dec 2012 00:54:58 +0100, u3557@miso.sublimeip.com wrote: > The beauty of using the x86 debug-registers,
x86 debug registers are already very scarce. Besides that userland applications know they have 4 of them available so it would also break them.
Regards, Jan
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