* Oleg Nesterov <o...@redhat.com> [2015-05-04 14:49:18]: > > fails if you probe func_1() and func_2() because handle_trampoline() > assumes that the probed function should must return and hit the bp > installed be prepare_uretprobe(). But in this case func_2() does not > return, so when func_1() returns the kernel uses the no longer valid > return_instance of func_2(). > > Change handle_trampoline() to unwind ->return_instances until we know > that the next chain is alive or NULL, this ensures that the current > chain is the last we need to report and free. > > Alternatively, every return_instance could use unique trampoline_vaddr, > in this case we could use it as a key. And this could solve the problem > with sigaltstack() automatically. > > But this approach needs more changes, and it puts the "hard" limit on > MAX_URETPROBE_DEPTH. Plus it can not solve another problem partially > fixed by the next patch. > > Note: this change has no effect on !x86, the arch-agnostic version of > arch_uretprobe_is_alive() just returns "true". > > TODO: as documented by the previous change, arch_uretprobe_is_alive() > can be fooled by sigaltstack/etc. > > Signed-off-by: Oleg Nesterov <o...@redhat.com> > ---
Looks good to me. Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> -- Thanks and Regards Srikar Dronamraju -- 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/
