* Oleg Nesterov <o...@redhat.com> [2012-11-14 19:49:53]: > This was always racy, but 268720903f87e0b84b161626c4447b81671b5d18 > "uprobes: Rework register_for_each_vma() to make it O(n)" should be > blamed anyway, it made everything worse and I didn't notice. > > register/unregister call build_map_info() and then do install/remove > breakpoint for every mm which mmaps inode/offset. This can obviously > race with fork()->dup_mmap() in between and we can miss the child. > > uprobe_register() could be easily fixed but unregister is much worse, > the new mm inherits "int3" from parent and there is no way to detect > this if uprobe goes away. > > So this patch simply adds percpu_down_read/up_read around dup_mmap(), > and percpu_down_write/up_write into register_for_each_vma(). > > This adds 2 new hooks into dup_mmap() but we can kill uprobe_dup_mmap() > and fold it into uprobe_end_dup_mmap(). >
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> > Reported-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> > Signed-off-by: Oleg Nesterov <o...@redhat.com> > --- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
