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Thomas Richter 1873f1547d perf probe: Add ustring support for perf probe command
Kernel commit 88903c4643 ("tracing/probe: Add ustring type for user-space string")
adds support for user-space strings when type 'ustring' is specified.

Here is an example using sysfs command line interface
for kprobes:

Function to probe:
  struct filename *
  getname_flags(const char __user *filename, int flags, int *empty)

Setup:
  # cd /sys/kernel/debug/tracing/
  # echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events
  # cat events/kprobes/tmr1/format | fgrep print
  print fmt: "(%lx) arg1=\"%s\"", REC->__probe_ip, REC->arg1
  # echo 1 > events/kprobes/tmr1/enable
  # touch /tmp/111
  # echo 0 > events/kprobes/tmr1/enable
  # cat trace|fgrep /tmp/111
  touch-5846  [005] d..2 255520.717960: tmr1:\
	  (getname_flags+0x0/0x400) arg1="/tmp/111"

Doing the same with the perf tool fails.
Using type 'string' succeeds:
 # perf probe "vfs_getname=getname_flags:72 pathname=filename:string"
 Added new event:
   probe:vfs_getname (on getname_flags:72 with pathname=filename:string)
   ....
 # perf probe -d probe:vfs_getname
 Removed event: probe:vfs_getname

However using type 'ustring' fails (output before):
 # perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
 Failed to write event: Invalid argument
   Error: Failed to add events.
 #

Fix this by adding type 'ustring' in function
convert_variable_type().

Using ustring succeeds (output after):
 # ./perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
 Added new event:
   probe:vfs_getname (on getname_flags:72 with pathname=filename:ustring)

 You can now use it in all perf tools, such as:

	perf record -e probe:vfs_getname -aR sleep 1

 #

Note: This issue also exists on x86, it is not s390 specific.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: sumanthk@linux.ibm.com
Link: http://lore.kernel.org/lkml/20200120132011.64698-2-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
History 2020-01-31 09:33:58 +01:00
arch Linux 5.5-rc7 2020-01-20 08:43:44 +01:00
block block: fix an integer overflow in logical block size 2020-01-15 21:43:09 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto tpmdd fixes for Linux v5.5-rc3 2019-12-18 17:17:36 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
drivers Linux 5.5-rc7 2020-01-20 08:43:44 +01:00
fs Linux 5.5-rc7 2020-01-20 08:43:44 +01:00
include Linux 5.5-rc7 2020-01-20 08:43:44 +01:00
init mm, debug_pagealloc: don't rely on static keys too early 2020-01-13 18:19:02 -08:00
ipc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kernel Merge branch 'core/kprobes' into perf/core, to pick up fixes 2020-01-28 07:59:05 +01:00
lib lib/vdso: Make __cvdso_clock_getres() static 2020-01-10 19:29:01 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: memcg/slab: call flush_memcg_workqueue() only if memcg workqueue is valid 2020-01-13 18:19:02 -08:00
net Linux 5.5-rc7 2020-01-20 08:43:44 +01:00
samples samples/seccomp: Zero out members based on seccomp_notif_sizes 2020-01-02 13:03:39 -08:00
scripts Kbuild fixes for v5.5 (2nd) 2020-01-03 11:21:25 -08:00
security + Bug fixes 2020-01-04 19:28:30 -08:00
sound sound fixes for 5.5-rc7 2020-01-17 08:38:35 -08:00
tools perf probe: Add ustring support for perf probe command 2020-01-31 09:33:58 +01:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-04 00:00:48 +09:00
virt PPC KVM fix for 5.5 2019-12-22 13:18:15 +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: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap MAINTAINERS: update my email address 2020-01-11 14:33:39 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
Makefile Linux 5.5-rc7 2020-01-19 16:02:49 -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.