cocci: Detect unlogged missed tail calls#11808
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This new Coccinelle script will detect tail calls (ep_tail_call() calls) that are not followed by either a call to send_drop_notify_error(arg1, arg2, DROP_MISSED_TAIL_CALL, ...) or return DROP_MISSED_TAIL_CALL. Tail calls in macros are not analyzed. The script cannot patch such unlogged tail calls as the correct fix depends on the context. It is up to the developer to fix any error found. Signed-off-by: Paul Chaignon <paul@cilium.io>
Without these changes, and because Coccinelle doesn't analyze the values of variables to prune branches, the new Coccinelle script detects the two tail calls as missing a subsequent DROP_MISSED_TAIL_CALL. Signed-off-by: Paul Chaignon <paul@cilium.io>
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The tail calls to tail_handle_ipv{4,6} will not be logged if they fail.
This commit fixes it.
Fixes: 9e108c1 ("nat46: Enable ipv6 containers to talk to an ipv4 container")
Signed-off-by: Paul Chaignon <paul@cilium.io>
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test-me-please |
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retest-gke |
qmonnet
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Jun 3, 2020
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Looks great!
Looks like a candidate for at least 1.8 backport to me, in case it helps catch or trace a bug in the future? Plus it should not be difficult to backport to 1.8.
borkmann
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Jun 3, 2020
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The first commit introduces a new Coccinelle script to detect tail calls not followed by a
DROP_MISSED_TAIL_CALLlog. The second commit adapts the code a bit in two places to allow Coccinelle to detect that all paths from tail call contain aDROP_MISSED_TAIL_CALLlog. The last commit fixes two instances of unlogged missed tail calls (dating from Cilium 0.10.1).@cilium/bpf Do we want to backport the two missing log for the tail calls?
Fixes: #190
Updates: #11257