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author | Delyan Kratunov <delyank@meta.com> | 2022-10-21 19:36:38 +0000 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2022-10-21 13:58:09 -0700 |
commit | eb814cf1adea0ce24413c26c22e9f1a556a45d34 (patch) | |
tree | 57f74ecffec4ad4400e21b78f6afe43007d9d3a9 /tools/lib | |
parent | 12f96823a9d7724f819424f6232d9e46a56e80d1 (diff) | |
download | linux-eb814cf1adea0ce24413c26c22e9f1a556a45d34.tar.bz2 |
selftests/bpf: fix task_local_storage/exit_creds rcu usage
BPF CI has revealed flakiness in the task_local_storage/exit_creds test.
The failure point in CI [1] is that null_ptr_count is equal to 0,
which indicates that the program hasn't run yet. This points to the
kern_sync_rcu (sys_membarrier -> synchronize_rcu underneath) not
waiting sufficiently.
Indeed, synchronize_rcu only waits for read-side sections that started
before the call. If the program execution starts *during* the
synchronize_rcu invocation (due to, say, preemption), the test won't
wait long enough.
As a speculative fix, make the synchornize_rcu calls in a loop until
an explicit run counter has gone up.
[1]: https://github.com/kernel-patches/bpf/actions/runs/3268263235/jobs/5374940791
Signed-off-by: Delyan Kratunov <delyank@meta.com>
Link: https://lore.kernel.org/r/156d4ef82275a074e8da8f4cffbd01b0c1466493.camel@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib')
0 files changed, 0 insertions, 0 deletions