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Masami Hiramatsu 499144c83d perf probe: Do not show non representive lines by perf-probe -L
Since perf probe -L shows non representive lines, it can be mislead
users where user can put probes.  This prevents to show such non
representive lines so that user can understand which lines user can
probe.

  # perf probe -L kernel_read
  <kernel_read@/build/linux-pvZVvI/linux-5.0.0/fs/read_write.c:0>
        0  ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
           {
        2         mm_segment_t old_fs;
                  ssize_t result;

                  old_fs = get_fs();
        6         set_fs(get_ds());
                  /* The cast to a user pointer is valid due to the set_fs() */
        8         result = vfs_read(file, (void __user *)buf, count, pos);
        9         set_fs(old_fs);
       10         return result;
           }
           EXPORT_SYMBOL(kernel_read);

Committer testing:

Before:

  # perf probe -L kernel_read
  <kernel_read@/usr/src/debug/kernel-5.3.fc30/linux-5.3.8-200.fc30.x86_64/fs/read_write.c:0>
        0  ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
        1  {
        2         mm_segment_t old_fs;
        3         ssize_t result;

        5         old_fs = get_fs();
        6         set_fs(KERNEL_DS);
                  /* The cast to a user pointer is valid due to the set_fs() */
        8         result = vfs_read(file, (void __user *)buf, count, pos);
        9         set_fs(old_fs);
       10         return result;
           }
           EXPORT_SYMBOL(kernel_read);
  #

See the 1, 3, 5 lines? They shouldn't be there, after this patch:

  # perf probe -L kernel_read
  <kernel_read@/usr/src/debug/kernel-5.3.fc30/linux-5.3.8-200.fc30.x86_64/fs/read_write.c:0>
        0  ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
           {
        2         mm_segment_t old_fs;
                  ssize_t result;

                  old_fs = get_fs();
        6         set_fs(KERNEL_DS);
                  /* The cast to a user pointer is valid due to the set_fs() */
        8         result = vfs_read(file, (void __user *)buf, count, pos);
        9         set_fs(old_fs);
       10         return result;
           }
           EXPORT_SYMBOL(kernel_read);
  #

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406473064.24476.2913278267727587314.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-11-18 18:59:36 -03:00
arch x86/insn: Add some Intel instructions to the opcode map 2019-11-18 18:54:45 -03:00
block blkcg: make blkcg_print_stat() print stats only for online blkgs 2019-11-06 17:08:38 -07:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation Documentation: TLS: Add missing counter description 2019-11-05 18:34:06 -08:00
drivers ARM: SoC fixes 2019-11-10 13:41:59 -08:00
fs configfs regression fix for 5.4-rc 2019-11-10 12:59:34 -08:00
include Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
lib lib: Remove select of inexistant GENERIC_IO 2019-11-10 10:38:43 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges 2019-11-06 08:47:50 -08:00
net vsock/virtio: fix sock refcnt holding during the shutdown 2019-11-08 12:17:50 -08:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts Modules fixes for v5.4-rc7 2019-11-08 09:48:19 -08:00
security Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
sound ASoC: Fixes for v5.4 2019-11-07 13:52:17 +01:00
tools perf probe: Do not show non representive lines by perf-probe -L 2019-11-18 18:59:36 -03:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt kvm: call kvm_arch_destroy_vm if vm creation fails 2019-10-31 12:13:16 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Linux 5.4-rc7 2019-11-11 07:59:06 +01:00
Makefile Linux 5.4-rc7 2019-11-10 16:17:15 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.