| Subject | Re: [PATCH v4 3.0-rc2-tip 2/22] 2: uprobes: Breakground page replacement. | From | Peter Zijlstra <> | Date | Fri, 10 Jun 2011 01:03:29 +0200 |
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On Tue, 2011-06-07 at 18:28 +0530, Srikar Dronamraju wrote: > + vaddr_old = kmap_atomic(old_page, KM_USER0); > + vaddr_new = kmap_atomic(new_page, KM_USER1); > + > + memcpy(vaddr_new, vaddr_old, PAGE_SIZE); > + /* poke the new insn in, ASSUMES we don't cross page boundary */ > + addr = vaddr; > + vaddr &= ~PAGE_MASK; > + memcpy(vaddr_new + vaddr, &opcode, uprobe_opcode_sz); > + > + kunmap_atomic(vaddr_new); > + kunmap_atomic(vaddr_old);
> + vaddr_new = kmap_atomic(page, KM_USER0); > + vaddr &= ~PAGE_MASK; > + memcpy(opcode, vaddr_new + vaddr, uprobe_opcode_sz); > + kunmap_atomic(vaddr_new); >
Both sequences in resp {write,read}_opcode() assume the opcode doesn't cross page boundaries but don't in fact have any assertions validating this assumption.
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