linux/tools
John Garry fc96ec4d5d perf metricgroup: Fix find_evsel_group() event selector
The following command segfaults on my x86 broadwell:

  $ ./perf stat  -M frontend_bound,retiring,backend_bound,bad_speculation sleep 1
  WARNING: grouped events cpus do not match, disabling group:
    anon group { raw 0x10e }
    anon group { raw 0x10e }
  perf: util/evsel.c:1596: get_group_fd: Assertion `!(!leader->core.fd)' failed.
  Aborted (core dumped)

The issue shows itself as a use-after-free in evlist__check_cpu_maps(),
whereby the leader of an event selector (evsel) has been deleted (yet we
still attempt to verify for an evsel).

Fundamentally the problem comes from metricgroup__setup_events() ->
find_evsel_group(), and has developed from the previous fix attempt in
commit 9c880c24cb ("perf metricgroup: Fix for metrics containing
duration_time").

The problem now is that the logic in checking if an evsel is in the same
group is subtly broken for the "cycles" event. For the "cycles" event,
the pmu_name is NULL; however the logic in find_evsel_group() may set an
event matched against "cycles" as used, when it should not be.

This leads to a condition where an evsel is set, yet its leader is not.

Fix the check for evsel pmu_name by not matching evsels when either has a
NULL pmu_name.

There is still a pre-existing metric issue whereby the ordering of the
metrics may break the 'stat' function, as discussed at:
https://lore.kernel.org/lkml/49c6fccb-b716-1bf0-18a6-cace1cdb66b9@huawei.com/

Fixes: 9c880c24cb ("perf metricgroup: Fix for metrics containing duration_time")
Signed-off-by: John Garry <john.garry@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> # On a Thinkpad T450S
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/1623335580-187317-2-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-06-19 10:06:46 -03:00
..
accounting
arch tools headers cpufeatures: Sync with the kernel sources 2021-06-11 12:54:24 -03:00
bootconfig tools/bootconfig: Fix a build error accroding to undefined fallthrough 2021-06-08 16:44:00 -04:00
bpf bpftool: Add sock_release help info for cgroup attach/prog load command 2021-05-25 16:18:32 +02:00
build tools build: Fix quiet cmd indentation 2021-05-17 12:10:03 +09:00
cgroup tools/cgroup/slabinfo.py: updated to work on current kernel 2021-04-23 14:42:40 -07:00
debugging tools: Fix a typo in kernel-chktaint 2021-04-08 11:41:22 -06:00
edid
firewire
firmware
gpio tools: gpio-utils: fix various kernel-doc warnings 2021-03-26 14:56:19 +01:00
hv
iio iio: event_monitor: Enable events before monitoring 2021-03-25 19:13:52 +00:00
include ARM fixes: 2021-05-29 06:02:25 -10:00
io_uring
kvm/kvm_stat tools/kvm_stat: Fix documentation typo 2021-05-07 06:06:22 -04:00
laptop
leds
lib libbpf: Fixes incorrect rx_ring_setup_done 2021-06-07 17:44:03 -07:00
memory-model doc: update rcu_dereference.rst reference 2021-04-06 14:45:04 +02:00
objtool objtool: Only rewrite unconditional retpoline thunk calls 2021-06-11 08:53:06 +02:00
pci
pcmcia
perf perf metricgroup: Fix find_evsel_group() event selector 2021-06-19 10:06:46 -03:00
power Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2021-05-05 12:24:29 -07:00
scripts tools build: Fix quiet cmd indentation 2021-05-17 12:10:03 +09:00
spi spi: tools: make a symbolic link to the header file spi.h 2021-04-22 16:30:39 +01:00
testing Networking fixes for 5.13-rc7, including fixes from wireless, bpf, 2021-06-18 18:55:29 -07:00
thermal/tmon tools: do not include scripts/Kbuild.include 2021-04-25 05:26:13 +09:00
time
tracing tools/latency-collector: Remove unneeded semicolon 2021-03-18 12:58:26 -04:00
usb treewide: remove editor modelines and cruft 2021-05-07 00:26:34 -07:00
virtio
vm
wmi
Makefile tracing/tools: Add the latency-collector to tools directory 2021-02-12 11:52:59 -05:00