* Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2011-01-26 11:11:48]: > On Wed, 2011-01-26 at 13:25 +0530, Srikar Dronamraju wrote: > > > > > > + > > > > + list_add(&mm->uprobes_list, &tmp_list); > > > > + mm->uprobes_vaddr = vma->vm_start + offset; > > > > + } > > > > + spin_unlock(&mapping->i_mmap_lock); > > > > > > Both this and unregister are racy, what is to say: > > > - the vma didn't get removed from the mm > > > - no new matching vma got added > > > > > > > register_uprobe, unregister_uprobe, uprobe_mmap are all synchronized by > > uprobes_mutex. So I dont see one unregister_uprobe getting thro when > > another register_uprobe is working with a vma. > > > > If I am missing something elementary, please explain a bit more. > > afaict you're not holding the mmap_sem, so userspace can simply unmap > the vma. When we do the actual insert/remove of the breakpoint we hold the mmap_sem. During the actual insertion/removal, if the vma for the specific inode is not found, we just come out without doing the actual insertion/deletion. -- 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>