From f1e8f25980968f7c18f1eb977bd1d5fd716325a5 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Mon, 20 Mar 2023 14:16:18 +0800 Subject: [PATCH] perf kvm: Reference count 'struct kvm_info' hists__add_entry_ops() doesn't allocate a new histogram entry if it has an existing entry for a KVM event, in this case, find_create_kvm_event() allocates a 'struct kvm_info' but it's not used by any histograms and never freed. To fix the memory leak, this patch first introduces a refcnt and a set of functions for refcnt operations on 'struct kvm_info'. When the data structure is not anymore used (the refcnt hits zero) kvm_info__zput() will free the memory used. Committer: Provide a nop version of kvm_info__zput() to be used when HAVE_KVM_STAT_SUPPORT isn't defined as it is used unconditionally in hists__findnew_entry() and hist_entry__delete(). Signed-off-by: Leo Yan Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230320061619.29520-2-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-kvm.c | 3 +-- tools/perf/util/hist.c | 5 +++++ tools/perf/util/kvm-stat.h | 40 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c index 4c205df5106f5..1e1cb5a9d0a2d 100644 --- a/tools/perf/builtin-kvm.c +++ b/tools/perf/builtin-kvm.c @@ -768,7 +768,6 @@ static void kvm_he_free(void *he) { struct kvm_event *kvm_ev; - free(((struct hist_entry *)he)->kvm_info); kvm_ev = container_of(he, struct kvm_event, he); free(kvm_ev); } @@ -788,7 +787,7 @@ static struct kvm_event *find_create_kvm_event(struct perf_kvm_stat *kvm, BUG_ON(key->key == INVALID_KEY); - ki = zalloc(sizeof(*ki)); + ki = kvm_info__new(); if (!ki) { pr_err("Failed to allocate kvm info\n"); return NULL; diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c index 0c11f50abfecf..b339ff863fe2b 100644 --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -628,6 +628,8 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists, block_info__zput(entry->block_info); + kvm_info__zput(entry->kvm_info); + /* If the map of an existing hist_entry has * become out-of-date due to an exec() or * similar, update it. Otherwise we will @@ -1324,6 +1326,9 @@ void hist_entry__delete(struct hist_entry *he) if (he->block_info) block_info__zput(he->block_info); + if (he->kvm_info) + kvm_info__zput(he->kvm_info); + zfree(&he->res_samples); zfree(&he->stat_acc); free_srcline(he->srcline); diff --git a/tools/perf/util/kvm-stat.h b/tools/perf/util/kvm-stat.h index bc6c8e38ef500..3e9ac754c3d1f 100644 --- a/tools/perf/util/kvm-stat.h +++ b/tools/perf/util/kvm-stat.h @@ -10,6 +10,9 @@ #include "symbol.h" #include "record.h" +#include +#include + #define KVM_EVENT_NAME_LEN 40 struct evsel; @@ -25,6 +28,7 @@ struct event_key { struct kvm_info { char name[KVM_EVENT_NAME_LEN]; + refcount_t refcnt; }; struct kvm_event_stats { @@ -145,6 +149,42 @@ extern const char *vcpu_id_str; extern const char *kvm_exit_reason; extern const char *kvm_entry_trace; extern const char *kvm_exit_trace; + +static inline struct kvm_info *kvm_info__get(struct kvm_info *ki) +{ + if (ki) + refcount_inc(&ki->refcnt); + return ki; +} + +static inline void kvm_info__put(struct kvm_info *ki) +{ + if (ki && refcount_dec_and_test(&ki->refcnt)) + free(ki); +} + +static inline void __kvm_info__zput(struct kvm_info **ki) +{ + kvm_info__put(*ki); + *ki = NULL; +} + +#define kvm_info__zput(ki) __kvm_info__zput(&ki) + +static inline struct kvm_info *kvm_info__new(void) +{ + struct kvm_info *ki; + + ki = zalloc(sizeof(*ki)); + if (ki) + refcount_set(&ki->refcnt, 1); + + return ki; +} + +#else /* HAVE_KVM_STAT_SUPPORT */ +// We use this unconditionally in hists__findnew_entry() and hist_entry__delete() +#define kvm_info__zput(ki) do { } while (0) #endif /* HAVE_KVM_STAT_SUPPORT */ extern int kvm_add_default_arch_event(int *argc, const char **argv); -- 2.30.2