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Masami Hiramatsu 7cd5738d0d perf probe: Fall back to debuginfod query if debuginfo and source not found locally
Since 'perf probe' heavily depends on debuginfo, debuginfod gives us
many benefits on the 'perf probe' command on remote machine.

Especially, this will be helpful for the embedded devices which will not
have enough storage, or boot with a cross-build kernel whose source code
is in the host machine.

This will work as similar to commit c7a14fdcb3 ("perf build-ids:
Fall back to debuginfod query if debuginfo not found")

Tested with:

  (host) $ cd PATH/TO/KBUILD/DIR/
  (host) $ debuginfod -F .
  ...

  (remote) # perf probe -L vfs_read
  Failed to find the path for the kernel: No such file or directory
    Error: Failed to show lines.

  (remote) # export DEBUGINFOD_URLS="http://$HOST_IP:8002/"
  (remote) # perf probe -L vfs_read
  <vfs_read@...>
        0  ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
           {
        2         ssize_t ret;

                  if (!(file->f_mode & FMODE_READ))
                          return -EBADF;
        6         if (!(file->f_mode & FMODE_CAN_READ))
                          return -EINVAL;
        8         if (unlikely(!access_ok(buf, count)))
                          return -EFAULT;

       11         ret = rw_verify_area(READ, file, pos, count);
       12         if (ret)
                          return ret;
                  if (count > MAX_RW_COUNT)
  ...

  (remote) # perf probe -a "vfs_read count"
  Added new event:
    probe:vfs_read       (on vfs_read with count)

  (remote) # perf probe -l
    probe:vfs_read       (on vfs_read@ksrc/linux/fs/read_write.c with count)

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Frank Ch. Eigler <fche@redhat.com>
Cc: Aaron Merey <amerey@redhat.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Link: http://lore.kernel.org/lkml/160041610083.912668.13659563860278615846.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-09-18 09:20:47 -03:00
Documentation ARM: SoC fixes 2020-09-13 14:54:40 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch vgacon: remove software scrollback support 2020-09-14 10:06:15 -07:00
block - Fix a regression in bdev partition locking (Christoph) 2020-09-11 11:55:28 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
drivers A handful of clk driver fixes. Mostly they're for error paths or 2020-09-16 11:52:56 -07:00
fs for-5.9-rc5-tag 2020-09-14 15:41:58 -07:00
include Driver core fixes for 5.9-rc5 2020-09-13 09:02:59 -07:00
init init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel seccomp fixes for v5.9-rc5 2020-09-12 12:58:01 -07:00
lib Driver core fixes for 5.9-rc5 2020-09-13 09:02:59 -07:00
mm xen: branch for v5.9-rc4 2020-09-06 09:59:27 -07:00
net NFS client bugfixes for Linux 5.9 2020-09-09 11:14:20 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts Char / Misc driver fixes for 5.9-rc5 2020-09-13 08:52:21 -07:00
security device_cgroup RCU warning fix from Amol Grover <frextrite@gmail.com> 2020-09-15 16:26:57 -07:00
sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools perf probe: Fall back to debuginfod query if debuginfo and source not found locally 2020-09-18 09:20:47 -03:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap mailmap, MAINTAINERS: move to tycho.pizza 2020-09-08 11:29:57 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Fix Max's and Shravan's emails 2020-09-16 11:51:02 -07:00
Makefile Linux 5.9-rc5 2020-09-13 16:06:00 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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 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.