On Tue, Feb 2, 2021 at 11:09 PM Nikolay Borisov <nborisov@xxxxxxxx> wrote:
>
>
>
> On 3.02.21 г. 9:06 ч., Alexei Starovoitov wrote:
> > From: Alexei Starovoitov <ast@xxxxxxxxxx>
> >
> > The commit 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
> > converted do_int3 handler to be "NMI-like".
> > That made old if (in_nmi()) check abort execution of bpf programs
> > attached to kprobe when kprobe is firing via int3
> > (For example when kprobe is placed in the middle of the function).
> > Remove the check to restore user visible behavior.
> >
> > Fixes: 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
> > Reported-by: Nikolay Borisov <nborisov@xxxxxxxx>
> > Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> Tested-by: Nikolay Borisov <nborisov@xxxxxxxx>
>
>
> So I take it you have verified the callpaths and deemed that it's safe
> to remove this check?
I stared a lot into different places. It's not pretty. I will follow up with
tightening patches for bpf-next, but I couldn't come up with anything
better for bpf tree.
