On 04/25/2018 07:42 AM, Gianluca Borello wrote:
> Commit 2a5418a13fcf ("bpf: improve dead code sanitizing") replaced dead
> code with a series of ja-1 instructions, for safety. That made JIT
> compilation much more complex for some BPF programs. One instance of such
> programs is, for example:
[...]
> A possible approach to mitigate this behavior consists into noticing that
> for ja-1 instructions we don't really need to rely on the estimated size
> of the previous and current instructions, we know that a -1 BPF jump
> offset can be safely translated into a 0xEB instruction with a jump offset
> of -2.
>
> Such fix brings the BPF program in the previous example to complete again
> in ~9 passes.
>
> Fixes: 2a5418a13fcf ("bpf: improve dead code sanitizing")
> Signed-off-by: Gianluca Borello <g.bore...@gmail.com>
Thanks for reporting, Gianluca. The approach your fix takes looks good to me!
