diff options
Diffstat (limited to 'tools/perf/Documentation/perf-dlfilter.txt')
-rw-r--r-- | tools/perf/Documentation/perf-dlfilter.txt | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-dlfilter.txt b/tools/perf/Documentation/perf-dlfilter.txt index fb22e3b31dc5..8887cc20a809 100644 --- a/tools/perf/Documentation/perf-dlfilter.txt +++ b/tools/perf/Documentation/perf-dlfilter.txt @@ -64,6 +64,12 @@ internal filtering. If implemented, 'filter_description' should return a one-line description of the filter, and optionally a longer description. +Do not assume the 'sample' argument is valid (dereferenceable) +after 'filter_event' and 'filter_event_early' return. + +Do not assume data referenced by pointers in struct perf_dlfilter_sample +is valid (dereferenceable) after 'filter_event' and 'filter_event_early' return. + The perf_dlfilter_sample structure ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -150,7 +156,8 @@ struct perf_dlfilter_fns { const char *(*srcline)(void *ctx, __u32 *line_number); struct perf_event_attr *(*attr)(void *ctx); __s32 (*object_code)(void *ctx, __u64 ip, void *buf, __u32 len); - void *(*reserved[120])(void *); + void (*al_cleanup)(void *ctx, struct perf_dlfilter_al *al); + void *(*reserved[119])(void *); }; ---- @@ -161,7 +168,8 @@ struct perf_dlfilter_fns { 'args' returns arguments from --dlarg options. 'resolve_address' provides information about 'address'. al->size must be set -before calling. Returns 0 on success, -1 otherwise. +before calling. Returns 0 on success, -1 otherwise. Call al_cleanup() (if present, +see below) when 'al' data is no longer needed. 'insn' returns instruction bytes and length. @@ -171,6 +179,12 @@ before calling. Returns 0 on success, -1 otherwise. 'object_code' reads object code and returns the number of bytes read. +'al_cleanup' must be called (if present, so check perf_dlfilter_fns.al_cleanup != NULL) +after resolve_address() to free any associated resources. + +Do not assume pointers obtained via perf_dlfilter_fns are valid (dereferenceable) +after 'filter_event' and 'filter_event_early' return. + The perf_dlfilter_al structure ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -197,9 +211,13 @@ struct perf_dlfilter_al { /* Below members are only populated by resolve_ip() */ __u8 filtered; /* true if this sample event will be filtered out */ const char *comm; + void *priv; /* Private data. Do not change */ }; ---- +Do not assume data referenced by pointers in struct perf_dlfilter_al +is valid (dereferenceable) after 'filter_event' and 'filter_event_early' return. + perf_dlfilter_sample flags ~~~~~~~~~~~~~~~~~~~~~~~~~~ |