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Filename Latest commit message Latest commit date
Adrian Hunter 854216d7ec perf intel-pt: Fix sample instruction bytes
commit c954eb72b31a9dc56c99b450253ec5b121add320 upstream.

The decoder reports the current instruction if it was decoded. In some
cases the current instruction is not decoded, in which case the instruction
bytes length must be set to zero. Ensure that is always done.

Note perf script can anyway get the instruction bytes for any samples where
they are not present.

Also note, that there is a redundant "ptq->insn_len = 0" statement which is
not removed until a subsequent patch in order to make this patch apply
cleanly to stable branches.

Example:

A machne that supports TSX is required. It will have flag "rtm". Kernel
parameter tsx=on may be required.

 # for w in `cat /proc/cpuinfo | grep -m1 flags `;do echo $w | grep rtm ; done
 rtm

Test program:

 #include <stdio.h>
 #include <immintrin.h>

 int main()
 {
        int x = 0;

        if (_xbegin() == _XBEGIN_STARTED) {
                x = 1;
                _xabort(1);
        } else {
                printf("x = %d\n", x);
        }
        return 0;
 }

Compile with -mrtm i.e.

 gcc -Wall -Wextra -mrtm xabort.c -o xabort

Record:

 perf record -e intel_pt/cyc/u --filter 'filter main @ ./xabort' ./xabort

Before:

 # perf script --itrace=xe -F+flags,+insn,-period --xed --ns
          xabort  1478 [007] 92161.431348581:   transactions:   x                              400b81 main+0x14 (/root/xabort)          mov $0xffffffff, %eax
          xabort  1478 [007] 92161.431348624:   transactions:   tx abrt                        400b93 main+0x26 (/root/xabort)          mov $0xffffffff, %eax

After:

 # perf script --itrace=xe -F+flags,+insn,-period --xed --ns
          xabort  1478 [007] 92161.431348581:   transactions:   x                              400b81 main+0x14 (/root/xabort)          xbegin 0x6
          xabort  1478 [007] 92161.431348624:   transactions:   tx abrt                        400b93 main+0x26 (/root/xabort)          xabort $0x1

Fixes: faaa87680b ("perf intel-pt/bts: Report instruction bytes and length in sample")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210519074515.9262-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-03 08:59:00 +02:00
arch openrisc: Fix a memory leak 2021-05-26 12:05:14 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation tweewide: Fix most Shebang lines 2021-05-22 11:38:30 +02:00
drivers iommu/vt-d: Fix sysfs leak in alloc_iommu() 2021-06-03 08:59:00 +02:00
fs NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return() 2021-06-03 08:59:00 +02:00
include NFC: nci: fix memory leak in nci_allocate_device 2021-05-28 13:10:27 +02:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-04-10 13:34:32 +02:00
ipc
kernel bpf: No need to simulate speculative domain for immediates 2021-05-28 13:10:26 +02:00
lib lib: stackdepot: turn depot_lock spinlock to raw_spinlock 2021-05-22 11:38:30 +02:00
LICENSES
mm mm/hugetlb: fix F_SEAL_FUTURE_WRITE 2021-05-19 10:08:29 +02:00
net NFC: nci: fix memory leak in nci_allocate_device 2021-05-28 13:10:27 +02:00
samples samples/bpf: Fix broken tracex1 due to kprobe argument change 2021-05-19 10:08:23 +02:00
scripts scripts: switch explicitly to Python 3 2021-05-22 11:38:30 +02:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ALSA: usb-audio: scarlett2: Improve driver startup messages 2021-06-03 08:59:00 +02:00
tools perf intel-pt: Fix sample instruction bytes 2021-06-03 08:59:00 +02:00
usr
virt KVM: arm64: Initialize VCPU mdcr_el2 before loading it 2021-05-22 11:38:30 +02:00
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Kconfig
MAINTAINERS
Makefile Linux 5.4.123 2021-05-28 13:10:27 +02:00
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.