linux/tools
Steve MacLean ee212d6ea2 perf map: Fix overlapped map handling
Whenever an mmap/mmap2 event occurs, the map tree must be updated to add a new
entry. If a new map overlaps a previous map, the overlapped section of the
previous map is effectively unmapped, but the non-overlapping sections are
still valid.

maps__fixup_overlappings() is responsible for creating any new map entries from
the previously overlapped map. It optionally creates a before and an after map.

When creating the after map the existing code failed to adjust the map.pgoff.
This meant the new after map would incorrectly calculate the file offset
for the ip. This results in incorrect symbol name resolution for any ip in the
after region.

Make maps__fixup_overlappings() correctly populate map.pgoff.

Add an assert that new mapping matches old mapping at the beginning of
the after map.

Committer-testing:

Validated correct parsing of libcoreclr.so symbols from .NET Core 3.0 preview9
(which didn't strip symbols).

Preparation:

  ~/dotnet3.0-preview9/dotnet new webapi -o perfSymbol
  cd perfSymbol
  ~/dotnet3.0-preview9/dotnet publish
  perf record ~/dotnet3.0-preview9/dotnet \
      bin/Debug/netcoreapp3.0/publish/perfSymbol.dll
  ^C

Before:

  perf script --show-mmap-events 2>&1 | grep -e MMAP -e unknown |\
     grep libcoreclr.so | head -n 4
        dotnet  1907 373352.698780: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615726000(0x768000) @ 0 08:02 5510620 765057155]: \
            r-xp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701091: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615974000(0x1000) @ 0x24e000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701241: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615c42000(0x1000) @ 0x51c000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.705249:     250000 cpu-clock: \
             7fe6159a1f99 [unknown] \
             (.../3.0.0-preview9-19423-09/libcoreclr.so)

After:

  perf script --show-mmap-events 2>&1 | grep -e MMAP -e unknown |\
     grep libcoreclr.so | head -n 4
        dotnet  1907 373352.698780: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615726000(0x768000) @ 0 08:02 5510620 765057155]: \
            r-xp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701091: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615974000(0x1000) @ 0x24e000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701241: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615c42000(0x1000) @ 0x51c000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so

All the [unknown] symbols were resolved.

Signed-off-by: Steve MacLean <Steve.MacLean@Microsoft.com>
Tested-by: Brian Robbins <brianrob@microsoft.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Cc: John Keeping <john@metanate.com>
Cc: John Salem <josalem@microsoft.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom McDonald <thomas.mcdonald@microsoft.com>
Link: http://lore.kernel.org/lkml/BN8PR21MB136270949F22A6A02335C238F7800@BN8PR21MB1362.namprd21.prod.outlook.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-09-30 17:29:46 -03:00
..
accounting
arch tools headers kvm: Sync kvm headers with the kernel sources 2019-09-30 17:29:30 -03:00
bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2019-09-06 16:49:17 +02:00
build tools build: Add capability-related feature detection 2019-08-12 17:14:14 -03:00
cgroup iocost_monitor: Report debt 2019-09-10 12:31:39 -06:00
debugging
firewire treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
firmware Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
gpio Bulk GPIO changes for the v5.3 kernel cycle: 2019-07-09 09:07:00 -07:00
hv - First round of vmbus hibernation support from Dexuan Cui. 2019-09-24 12:36:31 -07:00
iio tools: iio: add .gitignore 2019-08-18 20:45:57 +01:00
include tools headers kvm: Sync kvm headers with the kernel sources 2019-09-30 17:29:30 -03:00
io_uring tools/io_uring: sync with liburing 2019-05-23 10:25:26 -06:00
kvm/kvm_stat treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499 2019-06-19 17:09:53 +02:00
laptop treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
leds leds: core: Add support for composing LED class device names 2019-07-25 20:07:52 +02:00
lib libsubcmd: Make _FORTIFY_SOURCE defines dependent on the feature 2019-09-27 09:26:14 -03:00
memory-model tools/memory-model: Update the informal documentation 2019-08-09 10:28:57 -07:00
nfsd
objtool Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-16 17:06:21 -07:00
pci pci-v5.3-changes 2019-07-15 20:44:49 -07:00
pcmcia treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 247 2019-06-19 17:09:08 +02:00
perf perf map: Fix overlapped map handling 2019-09-30 17:29:46 -03:00
power platform-drivers-x86 for v5.4-2 2019-09-24 12:39:40 -07:00
scripts perf build: Do not use -Wshadow on gcc < 4.8 2019-07-23 09:04:54 -03:00
spi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 178 2019-05-30 11:29:19 -07:00
testing linux-kselftest-5.4-rc1.1 2019-09-26 12:25:15 -07:00
thermal/tmon treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 89 2019-05-24 17:37:52 +02:00
time treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
usb usbip: tools: fix GCC8 warning for strncpy 2019-07-25 18:12:20 +02:00
virtio treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482 2019-06-19 17:09:52 +02:00
vm tools/vm/slabinfo: add sorting info to help menu 2019-07-12 11:05:46 -07:00
wmi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
Makefile tools: Keep list of tools in alphabetical order 2019-08-14 10:59:59 -03:00