Messages in this thread | | | Date | Thu, 8 Mar 2012 14:48:09 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] uprobes/core: handle breakpoint and signal step exception. |
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* Srikar Dronamraju <srikar@linux.vnet.ibm.com> wrote:
> @@ -233,9 +233,11 @@ static inline void __user *arch_compat_alloc_user_space(long len) > > if (test_thread_flag(TIF_IA32)) { > sp = task_pt_regs(current)->sp; > +#ifdef CONFIG_X86_64 > } else { > /* -128 for the x32 ABI redzone */ > sp = __this_cpu_read(old_rsp) - 128; > +#endif > } > > return (void __user *)round_down(sp - len, 16);
So 'sp' is undefined if that TIF check fails?
Also, on a 32-bit kernel the TIF check probably fails all the time, because we don't set TIF_IA32 (and don't know that flag).
It would probably be better to make the whole helper inline #ifdef 64-bit, it does not look very useful on 32-bit.
Thanks,
Ingo
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