Hi all,
Today's linux-next merge of the net-next tree got a conflict in:
kernel/bpf/syscall.c
between commits:
6b1bb01bcc5b ("bpf: fix cb access in socket filter programs on tail calls")
c2002f983767 ("bpf: fix checking xdp_adjust_head on tail calls")
from the net tree and commit:
e245c5c6a565 ("bpf: move fixup_bpf_calls() function")
79741b3bdec0 ("bpf: refactor fixup_bpf_calls()")
from the net-next tree.
I fixed it up (the latter moved and changed teh code modified by the
former - I added the following fix up patch) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging. You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.
From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Date: Tue, 18 Apr 2017 10:16:03 +1000
Subject: [PATCH] bpf: merge fix for move of fixup_bpf_calls()
Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 62e1e447ded9..5939b4c81fe1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3349,6 +3349,14 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
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 the interpeter for every normal
* call and to prevent accidental JITing by JIT compiler
--
2.11.0
--
Cheers,
Stephen Rothwell
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