Messages in this thread | | | Date | Thu, 18 Jun 2015 11:33:15 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 5/5] x86/asm/entry/32: Simplify ptrace register shuffling |
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* Denys Vlasenko <dvlasenk@redhat.com> wrote:
> Before this patch, we were clearing pt_regs->r8..r11 on stack. > We can as well just store actual r8..r11 registers there: > they came from userspace, we leak no information by showing them to ptrace. > This allows to get rid of one insn ("xor %eax,%eax"). > Not a big deal, but still... > > After call to syscall_trace_enter(), before this patch we were restoring > clobbered registers and jump to code which converts 32-bit syscall > ABI to 64-bit C ABI. This is unnecessary work, we can combine both > steps into one (similar to what audit code does already).
So this really needs a description about what kind of testing was done, as technically this changes the ABI. Heavy ptrace users should be tried: strace, UML, etc.
I don't expect any problems, but still it needs to be tested.
Thanks,
Ingo
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