mirror of
https://github.com/torvalds/linux.git
synced 2026-10-12 05:17:15 +02:00
Linux kernel source tree
93ce3bee31
Executing the test_maps binary on platforms with extremely high core counts may cause intermittent assertion failures in test_update_delete() (called via test_map_parallel()). This can occur because bpf_map_update_elem() under some circumstances (specifically in this case while performing bpf_map_update_elem() with BPF_NOEXIST on a BPF_MAP_TYPE_HASH with its map_flags set to BPF_F_NO_PREALLOC) can return an E2BIG error code i.e. error -7 7 tools/testing/selftests/bpf/test_maps.c:#: void test_update_delete(unsigned int, void *): Assertion `err == 0' failed. tools/testing/selftests/bpf/test_maps.c:#: void __run_parallel(unsigned int, void (*)(unsigned int, void *), void *): Assertion `status == 0' failed. As it turns out, is_map_full() which is called from alloc_htab_elem() can take on a conservative approach when htab->use_percpu_counter is true (which is the case here because the percpu_counter is used when a BPF_MAP_TYPE_HASH is created with its map_flags set to BPF_F_NO_PREALLOC). This conservative approach prioritizes preventing over-allocation and potential issues that could arise from possibly exceeding htab->map.max_entries in highly concurrent environments, even if it means slightly under-utilizing the htab map's capacity. Given that bpf_map_update_elem() from test_update_delete() can return E2BIG, update can_retry() such that it also accounts for the E2BIG error code (specifically only when running with map_flags being set to BPF_F_NO_PREALLOC). The retry loop will allow the global count belonging to the percpu_counter to become synchronized and better reflect the current htab map's capacity. Signed-off-by: Matt Bobrowski <mattbobrowski@google.com> Acked-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20251113092519.2632079-1-mattbobrowski@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.