From: Ido Schimmel <idosch@idosch.org>
To: John Fastabend <john.fastabend@gmail.com>
Cc: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org, ast@kernel.org,
daniel@iogearbox.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] bpf: return EOPNOTSUPP when JIT is needed and not possible
Date: Thu, 9 Dec 2021 21:31:44 +0200 [thread overview]
Message-ID: <YbJZoK+qBEiLAxxM@shredder> (raw)
In-Reply-To: <61b2536e5161d_6bfb2089@john.notmuch>
On Thu, Dec 09, 2021 at 11:05:18AM -0800, John Fastabend wrote:
> Thadeu Lima de Souza Cascardo wrote:
> > When a CBPF program is JITed and CONFIG_BPF_JIT_ALWAYS_ON is enabled, and
> > the JIT fails, it would return ENOTSUPP, which is not a valid userspace
> > error code. Instead, EOPNOTSUPP should be returned.
> >
> > Fixes: 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config")
> > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> > ---
> > kernel/bpf/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> > index de3e5bc6781f..5c89bae0d6f9 100644
> > --- a/kernel/bpf/core.c
> > +++ b/kernel/bpf/core.c
> > @@ -1931,7 +1931,7 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
> > fp = bpf_int_jit_compile(fp);
> > bpf_prog_jit_attempt_done(fp);
> > if (!fp->jited && jit_needed) {
> > - *err = -ENOTSUPP;
> > + *err = -EOPNOTSUPP;
> > return fp;
> > }
> > } else {
> > --
> > 2.32.0
> >
>
> It seems BPF subsys returns ENOTSUPP in multiple places. This fixes one
> paticular case and is user facing. Not sure we want to one-off fix them
> here creating user facing changes over multiple kernel versions. On the
> fence with this one curious to see what others think. Haven't apps
> already adapted to the current convention or they don't care?
Similar issue was discussed in the past. See:
https://lore.kernel.org/netdev/20191204.125135.750458923752225025.davem@davemloft.net/
next prev parent reply other threads:[~2021-12-09 19:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 13:40 [PATCH] bpf: return EOPNOTSUPP when JIT is needed and not possible Thadeu Lima de Souza Cascardo
2021-12-09 19:05 ` John Fastabend
2021-12-09 19:31 ` Ido Schimmel [this message]
2021-12-09 23:03 ` Daniel Borkmann
2021-12-10 2:23 ` Jakub Kicinski
2021-12-10 12:24 ` Thadeu Lima de Souza Cascardo
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