9fb156bb82
Due to various bugs in tests clean up code (usually), if host system is misconfigured, it happens that test_progs will just crash in the middle of running a test with little to no indication of where and why the crash happened. For cases where coredump is not readily available (e.g., inside a CI), it's very helpful to have a stack trace, which lead to crash, to be printed out. This change adds a signal handler that will capture and print out symbolized backtrace: $ sudo ./test_progs -t mmap test_mmap:PASS:skel_open_and_load 0 nsec test_mmap:PASS:bss_mmap 0 nsec test_mmap:PASS:data_mmap 0 nsec Caught signal #11! Stack trace: ./test_progs(crash_handler+0x18)[0x42a888] /lib64/libpthread.so.0(+0xf5d0)[0x7f2aab5175d0] ./test_progs(test_mmap+0x3c0)[0x41f0a0] ./test_progs(main+0x160)[0x407d10] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f2aab15d3d5] ./test_progs[0x407ebc] [1] 1988412 segmentation fault (core dumped) sudo ./test_progs -t mmap Unfortunately, glibc's symbolization support is unable to symbolize static functions, only global ones will be present in stack trace. But it's still a step forward without adding extra libraries to get a better symbolization. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200225000847.3965188-1-andriin@fb.com
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 Restructured Text 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.