Re: [PATCH bpf-next v2] bpf: handle MADV_PAGEOUT error in uprobe_multi.c

[Jiri Olsa <olsajiri@gmail.com>]

On Mon, Oct 21, 2024 at 04:07:15PM +0800, Jason Xing wrote:
> On Mon, Oct 21, 2024 at 3:51 PM Jason Xing <kerneljasonxing@gmail.com> wrote:
> >
> > On Mon, Oct 21, 2024 at 3:41 PM Jiri Olsa <olsajiri@gmail.com> wrote:
> > >
> > > On Mon, Oct 21, 2024 at 01:07:06PM +0800, Jason Xing wrote:
> > > > From: Jason Xing <kernelxing@tencent.com>
> > > >
> > > > When I compiled the tools/testing/selftests/bpf, the following error
> > > > pops out:
> > > > uprobe_multi.c: In function ‘trigger_uprobe’:
> > > > uprobe_multi.c:109:26: error: ‘MADV_PAGEOUT’ undeclared (first use in this function); did you mean ‘MADV_RANDOM’?
> > > >    madvise(addr, page_sz, MADV_PAGEOUT);
> > > >                           ^~~~~~~~~~~~
> > > >                           MADV_RANDOM
> > > >
> > > > Including the <linux/linux/mman.h> header file solves this compilation error.
> > >
> > > hi,
> > > strange, uprobe_multi.c even has:
> > >
> > > #ifndef MADV_PAGEOUT
> > > #define MADV_PAGEOUT 21
> > > #endif
> > >
> > > and '#include <sys/mman.h>' should be all that's needed
> > >
> > > could you please share more details (extra flags) on how you compile?
> >
> > OMG, thanks for reminding me. The net-next branch that I compiled
> > doesn't have those three lines. Now I can see them in bpf-next. So I
> > think the issue has been fixed already :)
> 
> Link is https://lore.kernel.org/bpf/d9846ceb-b758-4c17-82d1-e5504122a50a@oracle.com/
> 
> The previous comment is not that right. Making sure to include
> <sys/mman.h> first solves the issue so there are no complaints when
> compiling. No need to define MADV_PAGEOUT, I think.

right, but looks like it was not enough on Alan's setup [1]

jirka


[1] c27d8235ba97 selftests/bpf: Fix uprobe_multi compilation error