test bpf tail calls #10117
Open
test bpf tail calls #10117
+3,248
−5
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
from
10ce4bd to
e5828a2
Compare
The bpf verifier checks whether packet data is modified within a helper function, and if so invalidates the pointer to that data. Currently the verifier always invalidates if the helper function called is a tail call, as it cannot tell whether the called function does or does not modify the packet data. However, in this case, the fact that the packet might be modified is irrelevant in the code following the helper call, as the tail call only returns if there is nothing to execute, otherwise the calling (sub)program will return directly after the tail call finished. So it is this (sub)program for which the pointer to packet data needs to be invalidated. Fortunately, there are already two distinct points in the code for invalidating packet pointers directly after a helper call, and for entire (sub)programs. This commit assures that the pointer is only invalidated in the relevant case. Signed-off-by: Martin Teichmann <[email protected]>
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
5 times, most recently
from
6d6792d to
4481a85
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.