| commit | c4675f935399cbdd3ba3869b0bf6c60528c8111a | |
| author | Daniel Borkmann <daniel@iogearbox.net> | |
| Mon, 13 Jul 2015 18:49:32 +0000 (13 20:49 +0200) | ||
| committer | David S. Miller <davem@davemloft.net> | |
| Mon, 13 Jul 2015 20:11:41 +0000 (13 13:11 -0700) | ||
| tree | f4ccb3f0c039382f2a3ce0a9247197a0712aeb03 | treesnapshot (tar.gz zip) |
| parent | de551f2eb22a77a498cea9686f39e79f25329109 | commitdiff |
ebpf: remove self-assignment in interpreter's tail call
ARG1 = BPF_R1 as it stands, evaluates to regs[BPF_REG_1] = regs[BPF_REG_1]
and thus has no effect. Add a comment instead, explaining what happens and
why it's okay to just remove it. Since from user space side, a tail call is
invoked as a pseudo helper function via bpf_tail_call_proto, the verifier
checks the arguments just like with any other helper function and makes
sure that the first argument (regs[BPF_REG_1])'s type is ARG_PTR_TO_CTX.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ARG1 = BPF_R1 as it stands, evaluates to regs[BPF_REG_1] = regs[BPF_REG_1]
and thus has no effect. Add a comment instead, explaining what happens and
why it's okay to just remove it. Since from user space side, a tail call is
invoked as a pseudo helper function via bpf_tail_call_proto, the verifier
checks the arguments just like with any other helper function and makes
sure that the first argument (regs[BPF_REG_1])'s type is ARG_PTR_TO_CTX.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| kernel/bpf/core.c | diffblobblamehistory |