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Linux kernel source tree
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When kernel is built without debuginfo, running 'perf record' with --off-cpu results in segfault as below: ./perf record --off-cpu -e dummy sleep 1 libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled? libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux libbpf: failed to find valid kernel BTF Segmentation fault (core dumped) The backtrace pointed to: #0 0x00000000100fb17c in btf.type_cnt () #1 0x00000000100fc1a8 in btf_find_by_name_kind () #2 0x00000000100fc38c in btf.find_by_name_kind () #3 0x00000000102ee3ac in off_cpu_prepare () #4 0x000000001002f78c in cmd_record () #5 0x00000000100aee78 in run_builtin () #6 0x00000000100af3e4 in handle_internal_command () #7 0x000000001001004c in main () Code sequence is: static void check_sched_switch_args(void) { struct btf *btf = btf__load_vmlinux_btf(); const struct btf_type *t1, *t2, *t3; u32 type_id; type_id = btf__find_by_name_kind(btf, "btf_trace_sched_switch", BTF_KIND_TYPEDEF); btf__load_vmlinux_btf() fails when CONFIG_DEBUG_INFO_BTF is not enabled. Here bpf__find_by_name_kind() calls btf__type_cnt() with NULL btf value and results in segfault. To fix this, add a check to see if btf is not NULL before invoking bpf__find_by_name_kind(). Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Disha Goel <disgoel@linux.vnet.ibm.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://lore.kernel.org/r/20241223135813.8175-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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| 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 | ||
| .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.