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Leo Yan a88259db27 perf tests: Fix out of bounds memory access
commit af8490eb2b upstream.

The test case 'Read backward ring buffer' failed on 32-bit architectures
which were found by LKFT perf testing.  The test failed on arm32 x15
device, qemu_arm32, qemu_i386, and found intermittent failure on i386;
the failure log is as below:

  50: Read backward ring buffer                  :
  --- start ---
  test child forked, pid 510
  Using CPUID GenuineIntel-6-9E-9
  mmap size 1052672B
  mmap size 8192B
  Finished reading overwrite ring buffer: rewind
  free(): invalid next size (fast)
  test child interrupted
  ---- end ----
  Read backward ring buffer: FAILED!

The log hints there have issue for memory usage, thus free() reports
error 'invalid next size' and directly exit for the case.  Finally, this
issue is root caused as out of bounds memory access for the data array
'evsel->id'.

The backward ring buffer test invokes do_test() twice.  'evsel->id' is
allocated at the first call with the flow:

  test__backward_ring_buffer()
    `-> do_test()
	  `-> evlist__mmap()
	        `-> evlist__mmap_ex()
	              `-> perf_evsel__alloc_id()

So 'evsel->id' is allocated with one item, and it will be used in
function perf_evlist__id_add():

   evsel->id[0] = id
   evsel->ids   = 1

At the second call for do_test(), it skips to initialize 'evsel->id'
and reuses the array which is allocated in the first call.  But
'evsel->ids' contains the stale value.  Thus:

   evsel->id[1] = id    -> out of bound access
   evsel->ids   = 2

To fix this issue, we will use evlist__open() and evlist__close() pair
functions to prepare and cleanup context for evlist; so 'evsel->id' and
'evsel->ids' can be initialized properly when invoke do_test() and avoid
the out of bounds memory access.

Fixes: ee74701ed8 ("perf tests: Add test to check backward ring buffer")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: stable@vger.kernel.org # v4.10+
Link: http://lore.kernel.org/lkml/20191107020244.2427-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17 19:56:23 +01:00
Documentation USB: documentation: flags on usb-storage versus UAS 2019-12-17 19:55:32 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch s390/mm: properly clear _PAGE_NOEXEC bit when it is not supported 2019-12-17 19:56:16 +01:00
block blk-mq: avoid sysfs buffer overflow with too many CPU cores 2019-12-17 19:56:14 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: user - fix memory leak in crypto_reportstat 2019-12-13 08:43:11 +01:00
drivers cpuidle: use first valid target residency as poll time 2019-12-17 19:56:23 +01:00
fs erofs: zero out when listxattr is called with no xattr 2019-12-17 19:56:23 +01:00
include media: cec.h: CEC_OP_REC_FLAG_ values were swapped 2019-12-17 19:56:20 +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 cgroup: pids: use atomic64_t for pids->limit 2019-12-17 19:56:15 +01:00
lib lib: raid6: fix awk build warnings 2019-12-17 19:56:09 +01:00
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-11-22 09:11:18 -08:00
net rfkill: allocate static minor 2019-12-13 08:43:18 +01:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts arm64 fix for -rc8 / final 2019-11-15 09:14:23 -08:00
security efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN 2019-10-31 09:40:21 +01:00
sound ASoC: fsl_audmix: Add spin lock to protect tdms 2019-12-17 19:56:14 +01:00
tools perf tests: Fix out of bounds memory access 2019-12-17 19:56:23 +01:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM: arm/arm64: vgic: Don't rely on the wrong pending table 2019-12-13 08:43:00 +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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4.3 2019-12-13 08:43:32 +01:00
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.