[PATCH bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures

[PATCH bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures

[Song Liu]

Instead of BUG_ON(), fail gracefully and return orig_prog.

Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
Signed-off-by: Song Liu <song@kernel.org>
---
 arch/x86/net/bpf_jit_comp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 643f38b91e30..08e8fd8f954a 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -2380,7 +2380,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 			 *
 			 * Both cases are serious bugs that we should not continue.
 			 */
-			BUG_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header));
+			if (WARN_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header))) {
+				prog = orig_prog;
+				goto out_addrs;
+			}
+
 			bpf_tail_call_direct_fixup(prog);
 		} else {
 			jit_data->addrs = addrs;
-- 
2.30.2

Re: [PATCH bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures

[Alexei Starovoitov]

On Mon, Feb 7, 2022 at 10:26 PM Song Liu <song@kernel.org> wrote:
>
> Instead of BUG_ON(), fail gracefully and return orig_prog.
>
> Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
> Signed-off-by: Song Liu <song@kernel.org>
> ---
>  arch/x86/net/bpf_jit_comp.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index 643f38b91e30..08e8fd8f954a 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -2380,7 +2380,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>                          *
>                          * Both cases are serious bugs that we should not continue.

I tweaked that comment a bit, since it's no longer accurate and
pushed to bpf-next.
Thanks!

>                          */
> -                       BUG_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header));
> +                       if (WARN_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header))) {
> +                               prog = orig_prog;
> +                               goto out_addrs;
> +                       }
> +
>                         bpf_tail_call_direct_fixup(prog);
>                 } else {
>                         jit_data->addrs = addrs;
> --
> 2.30.2
>

Re: [PATCH bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Mon, 7 Feb 2022 22:25:33 -0800 you wrote:
> Instead of BUG_ON(), fail gracefully and return orig_prog.
> 
> Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
> Signed-off-by: Song Liu <song@kernel.org>
> ---
>  arch/x86/net/bpf_jit_comp.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Here is the summary with links:
  - [bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures
    https://git.kernel.org/bpf/bpf-next/c/f95f768f0af4

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH bpf-next] bpf, x86_64: fail gracefully on bpf_jit_binary_pack_finalize failures

[Song Liu]

> On Feb 8, 2022, at 9:28 AM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> 
> On Mon, Feb 7, 2022 at 10:26 PM Song Liu <song@kernel.org> wrote:
>> 
>> Instead of BUG_ON(), fail gracefully and return orig_prog.
>> 
>> Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc")
>> Signed-off-by: Song Liu <song@kernel.org>
>> ---
>> arch/x86/net/bpf_jit_comp.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>> 
>> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
>> index 643f38b91e30..08e8fd8f954a 100644
>> --- a/arch/x86/net/bpf_jit_comp.c
>> +++ b/arch/x86/net/bpf_jit_comp.c
>> @@ -2380,7 +2380,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>>                         *
>>                         * Both cases are serious bugs that we should not continue.
> 
> I tweaked that comment a bit, since it's no longer accurate and
> pushed to bpf-next.
> Thanks!

Thanks for the fix! I had that in mind initially, but forgot about it
when I got to the keyboard. 

Song