Arnaldo Carvalho de Melo 7a46404b3c perf lzma: Convert some pr_err() to pr_debug() as callers already use pr_debug()
I noticed some error with:

  # perf list ex_ret_brn
  lzma: fopen failed on /usr/lib/modules/5.15.14-100.fc34.x86_64/kernel/net/bluetooth/bnep/bnep.ko.xz: 'No such file or directory'
  lzma: fopen failed on /usr/lib/modules/5.16.16-200.fc35.x86_64/kernel/drivers/gpu/drm/drm_kms_helper.ko.xz: 'No such file or directory'
  lzma: fopen failed on /usr/lib/modules/5.18.16-200.fc36.x86_64/kernel/arch/x86/crypto/crct10dif-pclmul.ko.xz: 'No such file or directory'
  lzma: fopen failed on /usr/lib/modules/5.16.16-200.fc35.x86_64/kernel/drivers/i2c/busses/i2c-piix4.ko.xz: 'No such file or directory'
  <BIG SNIP>

Then using 'perf probe' + 'perf trace' to debug 'perf list', it seems
its some inconsistency in the ~/.debug/ cache where broken build id
symlinks that ends up making it try to uncompress some kernel modules
using the lzma routines:

   395.309 perf/3594447 probe_perf:lzma_decompress_to_file(__probe_ip: 6118448, input_string: "/usr/lib/modules/5.18.17-200.fc36.x86_64/kernel/drivers/nvme/host/nvme.ko.xz")
                                       lzma_decompress_to_file (/var/home/acme/bin/perf)
                                       filename__decompress (/var/home/acme/bin/perf)
                                       filename__read_build_id (/var/home/acme/bin/perf)
                                       filename__sprintf_build_id (inlined)
                                       build_id_cache__valid_id (inlined)
                                       build_id_cache__list_all (/var/home/acme/bin/perf)
                                       print_sdt_events (/var/home/acme/bin/perf)
                                       cmd_list (/var/home/acme/bin/perf)
                                       run_builtin (/var/home/acme/bin/perf)
                                       handle_internal_command (inlined)
                                       run_argv (inlined)
                                       main (/var/home/acme/bin/perf)
                                       __libc_start_call_main (/usr/lib64/libc.so.6)
                                       __libc_start_main@@GLIBC_2.34 (/usr/lib64/libc.so.6)
                                       _start (/var/home/acme/bin/perf)

But callers of filename__decompress() already check its return and use
pr_debug(), so be consistent and make functions it calls also use
pr_debug().

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/ZOUD0+GkuCVkYF7n@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-08-22 16:53:32 -03:00
2022-09-28 09:02:20 +02:00
2023-08-06 15:07:51 -07:00

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.
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