73b97bc78b
Under full preemptible kernel, task local storage lookup operations on the same CPU may update per-cpu bpf_task_storage_busy concurrently. If the update of bpf_task_storage_busy is not preemption safe, the final value of bpf_task_storage_busy may become not-zero forever and bpf_task_storage_trylock() will always fail. So add a test case to ensure the update of bpf_task_storage_busy is preemption safe. Will skip the test case when CONFIG_PREEMPT is disabled, and it can only reproduce the problem probabilistically. By increasing TASK_STORAGE_MAP_NR_LOOP and running it under ARM64 VM with 4-cpus, it takes about four rounds to reproduce: > test_maps is modified to only run test_task_storage_map_stress_lookup() $ export TASK_STORAGE_MAP_NR_THREAD=256 $ export TASK_STORAGE_MAP_NR_LOOP=81920 $ export TASK_STORAGE_MAP_PIN_CPU=1 $ time ./test_maps test_task_storage_map_stress_lookup(135):FAIL:bad bpf_task_storage_busy got -2 real 0m24.743s user 0m6.772s sys 0m17.966s Signed-off-by: Hou Tao <houtao1@huawei.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/r/20220901061938.3789460-5-houtao@huaweicloud.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> |
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| .. | ||
| accounting | ||
| arch | ||
| bootconfig | ||
| bpf | ||
| build | ||
| certs | ||
| cgroup | ||
| counter | ||
| debugging | ||
| edid | ||
| firewire | ||
| firmware | ||
| gpio | ||
| hv | ||
| iio | ||
| include | ||
| io_uring | ||
| kvm/kvm_stat | ||
| laptop | ||
| leds | ||
| lib | ||
| memory-model | ||
| objtool | ||
| pci | ||
| pcmcia | ||
| perf | ||
| power | ||
| rcu | ||
| scripts | ||
| spi | ||
| testing | ||
| thermal | ||
| time | ||
| tracing | ||
| usb | ||
| verification | ||
| virtio | ||
| vm | ||
| wmi | ||
| Makefile | ||