Messages in this thread | | | Date | Fri, 29 Nov 2013 19:35:58 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH] Add a text_poke syscall v2 |
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On 11/25, Andi Kleen wrote: > > + err = get_user_pages_fast((unsigned long)addr, npages, 1, pages); > + if (err < 0) > + return err; > + if (err != npages) { > + err = -EFAULT; > + goto out; > + } > + err = 0; > + mutex_lock(&text_mutex); > + bp_target_mm = current->mm; > + bp_int3_addr = (u8 *)addr + 1; > + __text_poke_bp(pages, > + (unsigned long)addr & ~PAGE_MASK, > + insn, len, handler);
We are going to change this user page, it seems that we need set_page_dirty() ?
Andi, et al. I am going to discuss the things I do not really understand, probably this can't make any sense, but...
I am wondering if sys_text_poke() can do something like
down_write(mmap_sem);
get_user_pages(write, page, vma);
ptep = page_check_address(...);
pte = ptep_clear_flush(ptep);
copy-opcode-to-page;
pte = pte_mkdirty(pte); set_pte_at(ptep, pte);
pte_unmap_unlock(...); up_write(mmap_sem);
?
Oleg.
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