Re: [PATCH] libtraceevent utest: exit test if mmap fails

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

Hi Steve,

On Tue, Jun 16, 2026 at 04:48:12PM -0400, Steven Rostedt wrote:
> On Mon, 15 Jun 2026 20:25:08 +0100
> Sudip Mukherjee <sudipm.mukherjee@gmail.com> wrote:
> 
> > Hi Steve,
> > 
> > On Fri, 29 May 2026 at 19:41, Steven Rostedt <rostedt@goodmis.org> wrote:
> > >
> > > On Tue, 26 May 2026 19:42:19 +0100
> > > Sudip Mukherjee <sudipm.mukherjee@gmail.com> wrote:
> > >  
> > > > CU_TEST() continues execution even if the test fails. It just records
> > > > that the test has failed and moves on.
> > > > So, when libtraceevent is built in a chroot, it can open
> > > > /sys/kernel/btf/vmlinux but fails in mmap stage and since CU_TEST()
> > > > does not stop so we get a segfault when tep_load_btf() tries to use
> > > > the mapped buffer.
> > > >
> > > > Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>  
> > >
> > > Thanks, but the real fix is here and I'm applying that one:
> > >
> > >   https://lore.kernel.org/all/d6e07cd6-cb78-4119-a048-920ca58b4830@tuxera.com/  
> > 
> > Tried it today, and the test still fails for me.
> 
> Thanks for letting me know. I currently just started a new job and I'm
> a bit overwhelmed. It may be a couple more weeks before I get to this.

Not sure if you had a chance to look at it. I was looking at it now while
updating the Debian package. It seems like btf_init() is failing when its
doing if (btf->hdr->hdr_len < sizeof(*btf->hdr)). Adding a debug there shows,
btf->hdr->hdr_len is 24 whereas sizeof(*btf->hdr) is 32.

Tried on a chroot and also on a VM, both shows the same problem in Debian.

-- 
Regards
Sudip