Re: [PATCH 1/4] perf map: fix overlapped map handling
On Sat, Sep 28, 2019 at 01:39:00AM +, Steve MacLean wrote: SNIP > 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: 25 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. > > Tested-by: Brian Robbins > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Mark Rutland > Cc: Alexander Shishkin > Cc: Jiri Olsa > Cc: Namhyung Kim > Cc: Stephane Eranian > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Steve MacLean Acked-by: Jiri Olsa thanks, jirka > --- > 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 5b83ed1..eec9b28 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 > #include > #include > #include > @@ -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); > -- > 2.7.4
[PATCH 1/4] 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: 25 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. Tested-by: Brian Robbins Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Cc: linux-kernel@vger.kernel.org Signed-off-by: Steve MacLean --- 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 5b83ed1..eec9b28 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 #include #include #include @@ -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); -- 2.7.4