From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
lkml <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
"Martin Lau" <kafai@fb.com>
Subject: Re: [PATCH bpf v2] bpftool: Don't crash on missing jited insns or ksyms
Date: Tue, 10 Dec 2019 13:31:50 -0800 [thread overview]
Message-ID: <20191210213148.kqd6xdvqjkh3zxst@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20191210132428.4470a7b0@cakuba.netronome.com>
On Tue, Dec 10, 2019 at 01:24:28PM -0800, Jakub Kicinski wrote:
> On Tue, 10 Dec 2019 22:09:55 +0100, Toke Høiland-Jørgensen wrote:
> > Jakub Kicinski <jakub.kicinski@netronome.com> writes:
> > > On Tue, 10 Dec 2019 19:14:12 +0100, Toke Høiland-Jørgensen wrote:
> > >> When the kptr_restrict sysctl is set, the kernel can fail to return
> > >> jited_ksyms or jited_prog_insns, but still have positive values in
> > >> nr_jited_ksyms and jited_prog_len. This causes bpftool to crash when trying
> > >> to dump the program because it only checks the len fields not the actual
> > >> pointers to the instructions and ksyms.
> > >>
> > >> Fix this by adding the missing checks.
> > >>
> > >> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> > >
> > > Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
> > >
> > > and
> > >
> > > Fixes: f84192ee00b7 ("tools: bpftool: resolve calls without using imm field")
> > >
> > > ?
> >
> > Yeah, guess so? Although I must admit it's not quite clear to me whether
> > bpftool gets stable backports, or if it follows the "only moving
> > forward" credo of libbpf?
>
> bpftool does not have a GH repo, and seeing strength of Alexei's
> arguments in the recent discussion - I don't think it will. So no
> reason for bpftool to be "special"
bpftool always was and will be a special user of libbpf.
next prev parent reply other threads:[~2019-12-10 21:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 18:14 [PATCH bpf v2] bpftool: Don't crash on missing jited insns or ksyms Toke Høiland-Jørgensen
2019-12-10 18:21 ` Martin Lau
2019-12-10 20:54 ` Jakub Kicinski
2019-12-10 21:09 ` Toke Høiland-Jørgensen
2019-12-10 21:24 ` Jakub Kicinski
2019-12-10 21:31 ` Alexei Starovoitov [this message]
2019-12-10 21:52 ` Jakub Kicinski
2019-12-10 22:53 ` Alexei Starovoitov
2019-12-11 13:08 ` Daniel Borkmann
2019-12-11 13:20 ` Toke Høiland-Jørgensen
2019-12-11 13:33 ` Daniel Borkmann
2019-12-11 13:01 ` Daniel Borkmann
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