[v1.15] bpf: improvements for tailcall error reporting #32332
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[ upstream commit 4135f5b ] The naming of ep_tail_call() is very misleading - it *doesn't* call to an endpoint's policy tail-call (in POLICY_CALL_MAP), and it's also used by programs that are *not* associated with an endpoint (eg. bpf_xdp and bpf_overlay). Instead it's used for a tail-call in the program's internal tail-call map. So start off with introducing a new helper with improved naming. Then let this helper return DROP_MISSED_TAIL_CALL (instead of every caller open-coding the same value), and also setting the index of the missed tail-call in `ext_err` where available. Finally steal a bit of compiler magic from the kernel, and enforce that callers check for returned errors. We've had too many cases in the past where we forgot to return the DROP_MISSED_TAIL_CALL. Then convert a few initial callers to demonstrate the usage. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit a5c091c ] When invoke_tailcall_if() expands into a tail-call, provide it with an `ext_err` parameter so that the index of a missed tail-call can be reported. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 7b5195e ] Allow tail_call_internal() to return the index of a missed tail-call. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 4746609 ] Switch the internal tail-calls in bpf_host to the new helper. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 174a338 ] Switch the internal tail-calls in bpf_overlay to the new helper. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 6d69016 ] Switch the internal tail-calls in nodeport.h to the new helper. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit d22b60f ] Switch the internal tail-calls in bpf_lxc to the new helper. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 24963eb ] Switch over some multicast code that was recently introduced. Then remove the deprecated wrapper, and its coccinelle infrastructure. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit b52df67 ] Add __must_check wrappers to ensure that callers handle the error. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit 33f01d1 ] Fix mismatched brackets in multicast code and add ENABLE_MULTICAST in MAX_OVERLAY_OPTIONS to check such mismatches during compile time in future. Signed-off-by: harsimran pabla <hpabla@isovalent.com> Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
…call [ upstream commit 8b0c05c ] Make it easier to differentiate between (1) a missed program-internal tailcall (as reported by tail_call_internal()) that indicates a bug in how the agent loads the BPF program, and (2) a missed tailcall to some endpoint's policy program, that can also occur due to inherent race conditions for packets that are in-flight while an endpoint is being terminated. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit c12a80f ] Ensure that the callers handle errors, and specify a more fine-grained drop reason. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
[ upstream commit de55fd8 ] Whether the tail-call is executed as dynamic or static is an implementation detail. Hide it in a generic tail_call_policy() helper. Suggested-by: Timo Beckers <timo@isovalent.com> Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
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ldelossa
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May 12, 2024
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@kaworu ping, I think CODEOWNERS wants you to sanity-check the new drop reason. |
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To improve the error reporting for missed tailcalls in the datapath, backport a bunch of recent upstream improvements. This will make it easier to diagnose drops for such errors, and hopefully also help to eliminate CI flakes in the upgrade/downgrade workflows.
The manual backport is needed due to some trivial contextual conflicts.
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