> > No, use get_user() not __get_user() or if you use the later, also use
> > access_ok(), and test the result in case it errors (if it does, you
> > probably want to just goto bad access and SEGV).
>
> OK, lets see what this gives us:
Hrm... did you change anything ? :-)
Ben.
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index c33c6de..1bf91d3 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -153,7 +153,8 @@ int __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long address,
> #ifdef DEBUG_DCBX
> const char *istr = NULL;
>
> - insn = *((unsigned long *)regs->nip);
> + insn = 0;
> + __get_user(insn, (unsigned long __user *)regs->nip);
> if (((insn >> (31-5)) & 0x3f) == 31) {
> if (((insn >> 1) & 0x3ff) == 1014) /* dcbz ? 0x3f6 */
> istr = "dcbz";
> @@ -171,27 +172,32 @@ int __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long address,
> dar = regs->gpr[rb];
> if (ra)
> dar += regs->gpr[ra];
> - if (dar != address && address != 0x00f0 && trap
> == 0x300)
> + if (dar != address && trap == 0x300)
> printk(KERN_CRIT "%s: address:%lx,
> dar:%lx!\n", istr, address, dar);
> if (!strcmp(istr, "dcbst") && is_write) {
> printk(KERN_CRIT "dcbst R%ld,R%ld = %lx
> as a store, fixing!\n",
> ra, rb, dar);
> is_write = 0;
> }
> -
> +#if 0
> if (trap == 0x300 && address != dar) {
> __asm__ ("mtdar %0" : : "r" (dar));
> return 0;
> }
> +#endif
> }
> }
> #endif
> if (address == 0x00f0 && trap == 0x300) {
> - pte_t *ptep;
> + //pte_t *ptep;
>
> /* This is from a dcbX or icbi insn gone bad, these
> * insn do not set DAR so we have to do it here instead
> */
> - insn = *((unsigned long *)regs->nip);
> + if (get_user(insn, (unsigned long __user *)regs->nip)) {
> + printk(KERN_CRIT "get_user failed, NIP:%lx\n",
> + regs->nip);
> + goto bad_area_nosemaphore;
> + }
>
> ra = (insn >> (31-15)) & 0x1f; /* Reg RA */
> rb = (insn >> (31-20)) & 0x1f; /* Reg RB */
> @@ -206,7 +212,7 @@ int __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long address,
> trap, address, dar, error_code, istr);
> #endif
> address = dar;
> -#if 1
> +#if 0
> if (is_write && get_pteptr(mm, dar, &ptep, NULL)) {
> pte_t my_pte = *ptep;
>
> @@ -216,7 +222,7 @@ int __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long address,
> }
> }
> #else
> - return 0;
> + //return 0;
> #endif
> }
> }
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