kernel.git/tools/perf/util/intel-pt.c, branch linux-5.10.y

perf intel-pt: Fix segfault in intel_pt_print_info() with uClibc

2022-10-26T11:25:54Z

commit 5a3d47071f0ced0431ef82a5fb6bd077ed9493db upstream. uClibc segfaulted because NULL was passed as the format to fprintf(). That happened because one of the format strings was missing and intel_pt_print_info() didn't check that before calling fprintf(). Add the missing format string, and check format is not NULL before calling fprintf(). Fixes: 11fa7cb86b56d361 ("perf tools: Pass Intel PT information for decoding MTC and CYC") Signed-off-by: Adrian Hunter Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20221012082259.22394-2-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf intel-pt: Fix error timestamp setting on the decoder error path

2021-12-17T09:14:42Z

commit 6665b8e4836caa8023cbc7e53733acd234969c8c upstream. An error timestamp shows the last known timestamp for the queue, but this is not updated on the error path. Fix by setting it. Fixes: f4aa081949e7b6 ("perf tools: Add Intel PT decoder") Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: stable@vger.kernel.org # v5.15+ Link: https://lore.kernel.org/r/20211210162303.2288710-8-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo [Adrian: Backport to v5.10] Signed-off-by: Adrian Hunter Signed-off-by: Greg Kroah-Hartman

perf intel-pt: Fix sample instruction bytes

2021-06-03T07:00:27Z

commit c954eb72b31a9dc56c99b450253ec5b121add320 upstream. The decoder reports the current instruction if it was decoded. In some cases the current instruction is not decoded, in which case the instruction bytes length must be set to zero. Ensure that is always done. Note perf script can anyway get the instruction bytes for any samples where they are not present. Also note, that there is a redundant "ptq->insn_len = 0" statement which is not removed until a subsequent patch in order to make this patch apply cleanly to stable branches. Example: A machne that supports TSX is required. It will have flag "rtm". Kernel parameter tsx=on may be required. # for w in `cat /proc/cpuinfo | grep -m1 flags `;do echo $w | grep rtm ; done rtm Test program: #include #include int main() { int x = 0; if (_xbegin() == _XBEGIN_STARTED) { x = 1; _xabort(1); } else { printf("x = %d\n", x); } return 0; } Compile with -mrtm i.e. gcc -Wall -Wextra -mrtm xabort.c -o xabort Record: perf record -e intel_pt/cyc/u --filter 'filter main @ ./xabort' ./xabort Before: # perf script --itrace=xe -F+flags,+insn,-period --xed --ns xabort 1478 [007] 92161.431348581: transactions: x 400b81 main+0x14 (/root/xabort) mov $0xffffffff, %eax xabort 1478 [007] 92161.431348624: transactions: tx abrt 400b93 main+0x26 (/root/xabort) mov $0xffffffff, %eax After: # perf script --itrace=xe -F+flags,+insn,-period --xed --ns xabort 1478 [007] 92161.431348581: transactions: x 400b81 main+0x14 (/root/xabort) xbegin 0x6 xabort 1478 [007] 92161.431348624: transactions: tx abrt 400b93 main+0x26 (/root/xabort) xabort $0x1 Fixes: faaa87680b25d ("perf intel-pt/bts: Report instruction bytes and length in sample") Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/20210519074515.9262-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf intel-pt: Fix IPC with CYC threshold

2021-03-04T10:38:09Z

[ Upstream commit 6af4b60033e0ce0332fcdf256c965ad41942821a ] The code assumed every CYC-eligible packet has a CYC packet, which is not the case when CYC thresholds are used. Fix by checking if a CYC packet is actually present in that case. Fixes: 5b1dc0fd1da06 ("perf intel-pt: Add support for samples to contain IPC ratio") Signed-off-by: Adrian Hunter Reviewed-by: Andi Kleen Cc: Jiri Olsa Link: https://lore.kernel.org/r/20210205175350.23817-4-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf intel-pt: Fix premature IPC

2021-03-04T10:38:09Z

[ Upstream commit 20aa39708a5999b7921b27482a756766272286ac ] The code assumed a change in cycle count means accurate IPC. That is not correct, for example when sampling both branches and instructions, or at a FUP packet (which is not CYC-eligible) address. Fix by using an explicit flag to indicate when IPC can be sampled. Fixes: 5b1dc0fd1da06 ("perf intel-pt: Add support for samples to contain IPC ratio") Signed-off-by: Adrian Hunter Reviewed-by: Andi Kleen Cc: Jiri Olsa Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/20210205175350.23817-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin

perf intel-pt: Fix "context_switch event has no tid" error

2020-09-17T19:08:43Z

A context_switch event can have no tid because pids can be detached from a task while the task is still running (in do_exit()). Note this won't happen with per-task contexts because then tracing stops at perf_event_exit_task() If a task with no tid gets preempted, or a dying task gets preempted and its parent releases it, when it subsequently gets switched back in, Intel PT will not be able to determine what task is running and prints an error "context_switch event has no tid". However, it is not really an error because the task is in kernel space and the decoder can continue to decode successfully. Fix by changing the error to be only a logged message, and make allowance for tid == -1. Example: Using 5.9-rc4 with Preemptible Kernel (Low-Latency Desktop) e.g. $ uname -r 5.9.0-rc4 $ grep PREEMPT .config # CONFIG_PREEMPT_NONE is not set # CONFIG_PREEMPT_VOLUNTARY is not set CONFIG_PREEMPT=y CONFIG_PREEMPT_COUNT=y CONFIG_PREEMPTION=y CONFIG_PREEMPT_RCU=y CONFIG_PREEMPT_NOTIFIERS=y CONFIG_DRM_I915_PREEMPT_TIMEOUT=640 CONFIG_DEBUG_PREEMPT=y # CONFIG_PREEMPT_TRACER is not set # CONFIG_PREEMPTIRQ_DELAY_TEST is not set Before: $ cat forkit.c #include #include #include int main() { pid_t child; int status = 0; child = fork(); if (child == 0) return 123; wait(&status); return 0; } $ gcc -o forkit forkit.c $ sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k & [1] 11016 $ taskset 2 ./forkit $ sudo pkill perf $ [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 17.262 MB perf.data ] [1]+ Terminated sudo ~/bin/perf record --kcore -a -m,64M -e intel_pt/cyc/k $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit context_switch event has no tid taskset 11019 [001] 66663.270045029: 1 instructions:k: ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms]) taskset 11019 [001] 66663.270201816: 1 instructions:k: ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms]) forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019 forkit 11019 [001] 66663.270420028: 1 instructions:k: ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms]) forkit 11019 [001] 66663.270648704: 1 instructions:k: ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms]) forkit 11019 [001] 66663.270833163: 1 instructions:k: ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms]) forkit 11019 [001] 66663.271092359: 1 instructions:k: ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms]) forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019) forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 11020/11020 forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019 forkit 11020 [001] 66663.271312066: 1 instructions:k: ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms]) forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019) forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11019/11019 forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11020/11020 forkit 11019 [001] 66663.271517241: 1 instructions:k: ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms]) forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386) After: $ sudo ~/bin/perf script --show-task-events --show-switch-events --itrace=iqqe-o -C 1 --ns | grep -C 2 forkit taskset 11019 [001] 66663.270045029: 1 instructions:k: ffffffffb1d9f844 strnlen_user+0xb4 ([kernel.kallsyms]) taskset 11019 [001] 66663.270201816: 1 instructions:k: ffffffffb1a83121 unmap_page_range+0x561 ([kernel.kallsyms]) forkit 11019 [001] 66663.270327553: PERF_RECORD_COMM exec: forkit:11019/11019 forkit 11019 [001] 66663.270420028: 1 instructions:k: ffffffffb1db9537 __clear_user+0x27 ([kernel.kallsyms]) forkit 11019 [001] 66663.270648704: 1 instructions:k: ffffffffb18829e6 do_user_addr_fault+0xf6 ([kernel.kallsyms]) forkit 11019 [001] 66663.270833163: 1 instructions:k: ffffffffb230a825 irqentry_exit_to_user_mode+0x15 ([kernel.kallsyms]) forkit 11019 [001] 66663.271092359: 1 instructions:k: ffffffffb1aea3d9 lock_page_memcg+0x9 ([kernel.kallsyms]) forkit 11019 [001] 66663.271207092: PERF_RECORD_FORK(11020:11020):(11019:11019) forkit 11019 [001] 66663.271234775: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 11020/11020 forkit 11020 [001] 66663.271238407: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019 forkit 11020 [001] 66663.271312066: 1 instructions:k: ffffffffb1a88140 handle_mm_fault+0x10 ([kernel.kallsyms]) forkit 11020 [001] 66663.271476225: PERF_RECORD_EXIT(11020:11020):(11019:11019) forkit 11020 [001] 66663.271497488: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt next pid/tid: 11019/11019 forkit 11019 [001] 66663.271500523: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11020/11020 forkit 11019 [001] 66663.271517241: 1 instructions:k: ffffffffb24012cd error_entry+0x6d ([kernel.kallsyms]) forkit 11019 [001] 66663.271664080: PERF_RECORD_EXIT(11019:11019):(1386:1386) forkit 11019 [001] 66663.271688752: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: -1/-1 :-1 -1 [001] 66663.271692086: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 11019/11019 :-1 -1 [001] 66663.271707466: 1 instructions:k: ffffffffb18eb096 update_load_avg+0x306 ([kernel.kallsyms]) Fixes: 86c2786994bd7c ("perf intel-pt: Add support for PERF_RECORD_SWITCH") Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Yu-cheng Yu Link: http://lore.kernel.org/lkml/20200909084923.9096-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Fix corrupt data after perf inject from

2020-09-01T15:15:52Z

Commit 42bbabed09ce6208 ("perf tools: Add hw_idx in struct branch_stack") changed the format of branch stacks in perf samples. When samples use this new format, a flag must be set in the corresponding event. Synthesized branch stacks generated from Intel PT were using the new format, but not setting the event attribute, leading to consumers seeing corrupt data. This patch fixes the issue by setting the event attribute to indicate use of the new format. Fixes: 42bbabed09ce6208 ("perf tools: Add hw_idx in struct branch_stack") Signed-off-by: Al Grant Acked-by: Adrian Hunter Reviewed-by: Mathieu Poirier Cc: Alexander Shishkin Cc: Andi Kleen Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse Cc: linux-arm-kernel@lists.infradead.org Link: http://lore.kernel.org/lkml/20200819084751.17686-2-leo.yan@linaro.org Signed-off-by: Leo Yan Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add support for decoding FUP/TIP only

2020-08-06T12:02:14Z

Use the new itrace 'q' option to add support for a mode of decoding that ignores TNT, does not walk object code, but gets the ip from FUP and TIP packets. Example: $ perf record -e intel_pt//u grep -rI pudding drivers [ perf record: Woken up 52 times to write data ] [ perf record: Captured and wrote 57.870 MB perf.data ] $ time perf script --itrace=bi | wc -l 58948289 real 1m23.863s user 1m23.251s sys 0m7.452s $ time perf script --itrace=biq | wc -l 3385694 real 0m4.453s user 0m4.455s sys 0m0.328s Signed-off-by: Adrian Hunter Reviewed-by: Andi Kleen Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20200710151104.15137-12-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Time filter logged perf events

2020-08-06T11:23:19Z

Change the debug logging (when used with the --time option) to time filter logged perf events, but allow that to be overridden by using "d+a" instead of plain "d". That can reduce the size of the log file. Signed-off-by: Adrian Hunter Reviewed-by: Andi Kleen Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20200710151104.15137-10-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Use itrace debug log flags to suppress some messages

2020-08-06T11:23:00Z

The "d" option may be followed by flags which affect what debug messages will or will not be logged. Each flag must be preceded by either '+' or '-'. The flags support by Intel PT are: -a Suppress logging of perf events Suppressing perf events is useful for decreasing the size of the log. Signed-off-by: Adrian Hunter Reviewed-by: Andi Kleen Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20200710151104.15137-9-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo