kernel/linux.git/tools/perf/util/session.c, branch v6.1.175

perf session: Fix handling when buffer exceeds 2 GiB

2025-10-19T14:23:06+00:00

[ Upstream commit c17dda8013495d8132c976cbf349be9949d0fbd1 ] If a user specifies an AUX buffer larger than 2 GiB, the returned size may exceed 0x80000000. Since the err variable is defined as a signed 32-bit integer, such a value overflows and becomes negative. As a result, the perf record command reports an error: 0x146e8 [0x30]: failed to process type: 71 [Unknown error 183711232] Change the type of the err variable to a signed 64-bit integer to accommodate large buffer sizes correctly. Fixes: d5652d865ea734a1 ("perf session: Add ability to skip 4GiB or more") Reported-by: Tamas Zsoldos Signed-off-by: Leo Yan Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Link: https://lore.kernel.org/r/20250808-perf_fix_big_buffer_size-v1-1-45f45444a9a4@arm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf inject: Fix leader sampling inserting additional samples

2024-10-17T13:21:01+00:00

[ Upstream commit 79bcd34e0f3da39fda841406ccc957405e724852 ] The processing of leader samples would turn an individual sample with a group of read values into multiple samples. 'perf inject' would pass through the additional samples increasing the output data file size: $ perf record -g -e "{instructions,cycles}:S" -o perf.orig.data true $ perf script -D -i perf.orig.data | sed -e 's/perf.orig.data/perf.data/g' > orig.txt $ perf inject -i perf.orig.data -o perf.new.data $ perf script -D -i perf.new.data | sed -e 's/perf.new.data/perf.data/g' > new.txt $ diff -u orig.txt new.txt --- orig.txt 2024-07-29 14:29:40.606576769 -0700 +++ new.txt 2024-07-29 14:30:04.142737434 -0700 ... -0xc550@perf.data [0x30]: event: 3 +0xc550@perf.data [0xd0]: event: 9 +. +. ... raw event: size 208 bytes +. 0000: 09 00 00 00 01 00 d0 00 fc 72 01 86 ff ff ff ff .........r...... +. 0010: 74 7d 2c 00 74 7d 2c 00 fb c3 79 f9 ba d5 05 00 t},.t},...y..... +. 0020: e6 cb 1a 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ +. 0030: 02 00 00 00 00 00 00 00 76 01 00 00 00 00 00 00 ........v....... +. 0040: e6 cb 1a 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ +. 0050: 62 18 00 00 00 00 00 00 f6 cb 1a 00 00 00 00 00 b............... +. 0060: 00 00 00 00 00 00 00 00 0c 00 00 00 00 00 00 00 ................ +. 0070: 80 ff ff ff ff ff ff ff fc 72 01 86 ff ff ff ff .........r...... +. 0080: f3 0e 6e 85 ff ff ff ff 0c cb 7f 85 ff ff ff ff ..n............. +. 0090: bc f2 87 85 ff ff ff ff 44 af 7f 85 ff ff ff ff ........D....... +. 00a0: bd be 7f 85 ff ff ff ff 26 d0 7f 85 ff ff ff ff ........&....... +. 00b0: 6d a4 ff 85 ff ff ff ff ea 00 20 86 ff ff ff ff m......... ..... +. 00c0: 00 fe ff ff ff ff ff ff 57 14 4f 43 fc 7e 00 00 ........W.OC.~.. + +1642373909693435 0xc550 [0xd0]: PERF_RECORD_SAMPLE(IP, 0x1): 2915700/2915700: 0xffffffff860172fc period: 1 addr: 0 +... FP chain: nr:12 +..... 0: ffffffffffffff80 +..... 1: ffffffff860172fc +..... 2: ffffffff856e0ef3 +..... 3: ffffffff857fcb0c +..... 4: ffffffff8587f2bc +..... 5: ffffffff857faf44 +..... 6: ffffffff857fbebd +..... 7: ffffffff857fd026 +..... 8: ffffffff85ffa46d +..... 9: ffffffff862000ea +..... 10: fffffffffffffe00 +..... 11: 00007efc434f1457 +... sample_read: +.... group nr 2 +..... id 00000000001acbe6, value 0000000000000176, lost 0 +..... id 00000000001acbf6, value 0000000000001862, lost 0 + +0xc620@perf.data [0x30]: event: 3 ... This behavior is incorrect as in the case above 'perf inject' should have done nothing. Fix this behavior by disabling separating samples for a tool that requests it. Only request this for `perf inject` so as to not affect other perf tools. With the patch and the test above there are no differences between the orig.txt and new.txt. Fixes: e4caec0d1af3d608 ("perf evsel: Add PERF_SAMPLE_READ sample related processing") Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ingo Molnar Cc: Jiri Olsa Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240729220620.2957754-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf cpumap: Add range data encoding

2022-10-04T11:55:21+00:00

Often cpumaps encode a range of all CPUs, add a compact encoding that doesn't require a bit mask or list of all CPUs. Signed-off-by: Ian Rogers Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexey Bayduraev Cc: Athira Jajeev Cc: Colin Ian King Cc: Dave Marchevsky Cc: German Gomez Cc: Gustavo A. R. Silva Cc: Ingo Molnar Cc: James Clark Cc: Kees Kook Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Riccardo Mancini Cc: Song Liu Cc: Stephane Eranian Link: https://lore.kernel.org/r/20220614143353.1559597-7-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Extend branch type classification

2022-10-04T11:55:20+00:00

This updates the perf tool with generic branch type classification with new ABI extender place holder i.e PERF_BR_EXTEND_ABI, the new 4 bit branch type field i.e perf_branch_entry.new_type, new generic page fault related branch types and some arch specific branch types as added earlier in the kernel. Committer note: Add an extra entry to the branch_type_name array to cope with PERF_BR_EXTEND_ABI, to address build warnings on some compiler/systems, like: 75 8.89 ubuntu:20.04-x-powerpc64el : FAIL gcc version 10.3.0 (Ubuntu 10.3.0-1ubuntu1~20.04) inlined from 'branch_type_stat_display' at util/branch.c:152:4: /usr/powerpc64le-linux-gnu/include/bits/stdio2.h:100:10: error: '%8s' directive argument is null [-Werror=format-overflow=] 100 | return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 101 | __va_arg_pack ()); | ~~~~~~~~~~~~~~~~~ Signed-off-by: Anshuman Khandual Cc: Alexander Shishkin Cc: Catalin Marinas Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Robin Murphy Cc: Stephen Rothwell Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20220824044822.70230-7-anshuman.khandual@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Support reading PERF_FORMAT_LOST

2022-08-19T18:56:56+00:00

The recent kernel added lost count can be read from either read(2) or ring buffer data with PERF_SAMPLE_READ. As it's a variable length data we need to access it according to the format info. But for perf tools use cases, PERF_FORMAT_ID is always set. So we can only check PERF_FORMAT_LOST bit to determine the data format. Add sample_read_value_size() and next_sample_read_value() helpers to make it a bit easier to access. Use them in all places where it reads the struct sample_read_value. Signed-off-by: Namhyung Kim Acked-by: Jiri Olsa Cc: Ian Rogers Cc: Ingo Molnar Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20220819003644.508916-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf cpumap: Fix alignment for masks in event encoding

2022-08-19T18:30:28+00:00

A mask encoding of a cpu map is laid out as: u16 nr u16 long_size unsigned long mask[]; However, the mask may be 8-byte aligned meaning there is a 4-byte pad after long_size. This means 32-bit and 64-bit builds see the mask as being at different offsets. On top of this the structure is in the byte data[] encoded as: u16 type char data[] This means the mask's struct isn't the required 4 or 8 byte aligned, but is offset by 2. Consequently the long reads and writes are causing undefined behavior as the alignment is broken. Fix the mask struct by creating explicit 32 and 64-bit variants, use a union to avoid data[] and casts; the struct must be packed so the layout matches the existing perf.data layout. Taking an address of a member of a packed struct breaks alignment so pass the packed perf_record_cpu_map_data to functions, so they can access variables with the right alignment. As the 64-bit version has 4 bytes of padding, optimizing writing to only write the 32-bit version. Committer notes: Disable warnings about 'packed' that break the build in some arches like riscv64, but just around that specific struct. Signed-off-by: Ian Rogers Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexey Bayduraev Cc: Athira Jajeev Cc: Colin Ian King Cc: Dave Marchevsky Cc: German Gomez Cc: Gustavo A. R. Silva Cc: Ingo Molnar Cc: James Clark Cc: Kees Kook Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Riccardo Mancini Cc: Song Liu Cc: Stephane Eranian Link: https://lore.kernel.org/r/20220614143353.1559597-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Automatically use guest kcore_dir if present

2022-07-20T14:08:37+00:00

When registering a guest machine using machine_pid from the id index, check perf.data for a matching kcore_dir subdirectory and set the kallsyms file name accordingly. If set, use it to find the machine's kernel symbols and object code (from kcore). Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220711093218.10967-23-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf auxtrace: Add machine_pid and vcpu to auxtrace_error

2022-07-20T14:08:17+00:00

Add machine_pid and vcpu to struct perf_record_auxtrace_error. The existing fmt member is used to identify the new format. The new members make it possible to easily differentiate errors from guest machines. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220711093218.10967-18-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf session: Use sample->machine_pid to find guest machine

2022-07-20T14:08:08+00:00

If machine_pid is set, use it to find the guest machine. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220711093218.10967-15-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add guest_cpu to hypervisor threads

2022-07-20T14:08:04+00:00

It is possible to know which guest machine was running at a point in time based on the PID of the currently running host thread. That is, perf identifies guest machines by the PID of the hypervisor. To determine the guest CPU, put it on the hypervisor (QEMU) thread for that VCPU. This is done when processing the id_index which provides the necessary information. Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220711093218.10967-13-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo