From: Steve MacLean Steve.MacLean@microsoft.com
[ Upstream commit ee212d6ea20887c0ef352be8563ca13dbf965906 ]
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@BN8PR21MB... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/map.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index c662fef95d144..df6892596dc27 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -1,4 +1,5 @@ #include "symbol.h" +#include <assert.h> #include <errno.h> #include <inttypes.h> #include <limits.h> @@ -716,6 +717,8 @@ 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) map__fprintf(after, fp);