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authorSteve MacLean <Steve.MacLean@microsoft.com>2019-09-28 01:39:00 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-09-30 17:29:46 -0300
commitee212d6ea20887c0ef352be8563ca13dbf965906 (patch)
tree058c7947e7b4cc70a2befc58966b0fa488aae9ee
parent0d0e5ecec6116db6031829299e74cc71240c9ff3 (diff)
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>
-rw-r--r--tools/perf/util/map.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 5b83ed1ebbd6..eec9b282c047 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include "symbol.h"
+#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
@@ -850,6 +851,8 @@ static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp
}
after->start = map->end;
+ after->pgoff += map->end - pos->start;
+ assert(pos->map_ip(pos, map->end) == after->map_ip(after, map->end));
__map_groups__insert(pos->groups, after);
if (verbose >= 2 && !use_browser)
map__fprintf(after, fp);