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| author | David S. Miller <davem@davemloft.net> | 2017-04-17 15:51:58 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-17 15:51:58 -0400 |
| commit | acf167f3f2495f0b6565f6e8ac9bd87158a0e98d (patch) | |
| tree | 82226511f5f60faf8c8bf820051da232e104c026 | |
| parent | 0aa8c13eb512823bc4d60397d666a6b6260bb965 (diff) | |
| parent | c2002f983767ea0a53acbb3e21f771e7a7e2ed28 (diff) | |
Merge branch 'bpf-fixes'
Daniel Borkmann says:
====================
Two BPF fixes
The set fixes cb_access and xdp_adjust_head bits in struct bpf_prog,
that are used for requirement checks on the program rather than f.e.
heuristics. Thus, for tail calls, we cannot make any assumptions and
are forced to set them.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | kernel/bpf/syscall.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7af0dcc5d755..821f9e807de5 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -617,6 +617,14 @@ static void fixup_bpf_calls(struct bpf_prog *prog) if (insn->imm == BPF_FUNC_xdp_adjust_head) prog->xdp_adjust_head = 1; if (insn->imm == BPF_FUNC_tail_call) { + /* If we tail call into other programs, we + * cannot make any assumptions since they + * can be replaced dynamically during runtime + * in the program array. + */ + prog->cb_access = 1; + prog->xdp_adjust_head = 1; + /* mark bpf_tail_call as different opcode * to avoid conditional branch in * interpeter for every normal call |