* Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2011-01-27 11:23:37]: > On Thu, 2011-01-27 at 15:31 +0530, Srikar Dronamraju wrote: > > > > > - validate that the vma is indeed a map of the right inode > > > > > > > > We can add a check in write_opcode( we need to pass the inode to > > > > write_opcode). > > > > > > sure.. > > > > > > > > - validate that the offset of the probe corresponds with the stored > > > > > address > > > > > > > > I am not clear on this. We would have derived the address from the > > > > offset. So is that we check for > > > > (vaddr == vma->vm_start + uprobe->offset) > > > > > > Sure, but the vma might have changed since you computed the offset -) > > > > If the vma has changed then it would fail the 2nd validation i.e vma > > corresponds to the uprobe inode right. If the vma was unmapped and > > mapped back at the same place, then I guess we are okay to probe. > > It can be unmapped and mapped back slightly different. A map of the same > file doesn't need to mean its in the exact same location or has the > exact same pgoffset. > > If its not at the exact same location, then our third validation of checking that (vaddr == vma->vm_start + uprobe->offset) should fail right? Also should it be (vaddr == uprobe->offset + vma->vm_start - vma->pgoff << PAGE_SHIFT) ? -- Thanks and Regards Srikar -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>