We faced segmentation fault on perf top -G at very high sampling rate due to a corrupted callchain. While the root cause was not revealed (I failed to figure it out), this patch tries to protect us from the segfault on such cases.
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| @@ -555,6 +555,8 @@ enum perf_event_type { · 554 unmodified lines | |||
| 555 | PERF_RECORD_MAX, /* non-ABI */ | 555 | PERF_RECORD_MAX, /* non-ABI */ |
| 556 | }; | 556 | }; |
| 557 | 557 | ||
| 558 | #define PERF_MAX_STACK_DEPTH 255 | ||
| 559 | |||
| 558 | enum perf_callchain_context { | 560 | enum perf_callchain_context { |
| 559 | PERF_CONTEXT_HV = (__u64)-32, | 561 | PERF_CONTEXT_HV = (__u64)-32, |
| 560 | PERF_CONTEXT_KERNEL = (__u64)-128, | 562 | PERF_CONTEXT_KERNEL = (__u64)-128, |
| @@ -609,8 +611,6 @@ struct perf_guest_info_callbacks { · 48 unmodified lines | |||
| 609 | #include <linux/sysfs.h> | 611 | #include <linux/sysfs.h> |
| 610 | #include <asm/local.h> | 612 | #include <asm/local.h> |
| 611 | 613 | ||
| 612 | #define PERF_MAX_STACK_DEPTH 255 | ||
| 613 | |||
| 614 | struct perf_callchain_entry { | 614 | struct perf_callchain_entry { |
| 615 | __u64 nr; | 615 | __u64 nr; |
| 616 | __u64 ip[PERF_MAX_STACK_DEPTH]; | 616 | __u64 ip[PERF_MAX_STACK_DEPTH]; |