From 0ebcdc40cc3bdd9c1bc5117aaaa278555e27f67a Mon Sep 17 00:00:00 2001 From: Steve MacLean Date: Sat, 28 Sep 2019 01:39:00 +0000 Subject: perf map: Fix overlapped map handling [ 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 Tested-by: Brian Robbins Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: Davidlohr Bueso Cc: Eric Saint-Etienne Cc: John Keeping Cc: John Salem Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Song Liu Cc: Stephane Eranian Cc: Tom McDonald Link: http://lore.kernel.org/lkml/BN8PR21MB136270949F22A6A02335C238F7800@BN8PR21MB1362.namprd21.prod.outlook.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- 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 c662fef95d14..df6892596dc2 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -1,4 +1,5 @@ #include "symbol.h" +#include #include #include #include @@ -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); -- cgit v1.2.3