On 11-27-16, Andy Lutomirski wrote: > On Sun, Nov 20, 2016 at 9:52 AM, Alexnader Kuleshov > <[email protected]> wrote: > > Hello everyone, > > > > Exception handlers which may run on IST stack disable and enable preemption > > twice. For example do_int3() [1]. This one calls ist_enter() which > > disables preemption with preempt_disable() every time without any > > conditions. > > And later do_int3() calls preempt_disable() again [2] before do_trap(). > > > > Of course we decrement preemption counter in the end of such exception > > handlers twice too. But what's actual purpose of doing this two times? > > > > [1] > > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/arch/x86/kernel/traps.c?id=refs/tags/next-20161117#n530 > > [2] > > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/arch/x86/kernel/traps.c?id=refs/tags/next-20161117#n566 > > > > Thank you. > > You could submit a patch to get rid of the extra one if you like.
Thanks for reply. Will send a patch.
