diff --git a/Documentation/trace/eprobetrace.rst b/Documentation/trace/eprobetrace.rst index 89b5157..fe36025 100644 --- a/Documentation/trace/eprobetrace.rst +++ b/Documentation/trace/eprobetrace.rst @@ -46,6 +46,10 @@ Synopsis of eprobe_events (x8/x16/x32/x64), VFS layer common type(%pd/%pD), "char", "string", "ustring", "symbol", "symstr" and "bitfield" are supported. + (STRUCT)FIELD->MEMBER[->MEMBER] : If BTF is supported, typecast FIELD to + a pointer to STRUCT and then derference the pointer defined by + ->MEMBER. Note that when this is used, the FIELD name does not + need to be prefixed with a '$'. Types ----- diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 44c22d4..fd1caa1 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -332,6 +332,23 @@ static int parse_trace_event_arg(char *arg, struct fetch_insn *code, return -ENOENT; } +static int parse_trace_event(char *arg, struct fetch_insn *code, + struct traceprobe_parse_context *ctx) +{ + int ret; + + if (code->data) + return -EFAULT; + ret = parse_trace_event_arg(arg, code, ctx); + if (!ret) + return 0; + if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { + code->op = FETCH_OP_COMM; + return 0; + } + return -EINVAL; +} + #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS static u32 btf_type_int(const struct btf_type *t) @@ -376,11 +393,16 @@ static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type) && BTF_INT_BITS(intdata) == 8; } +static struct btf *ctx_btf(struct traceprobe_parse_context *ctx) +{ + return ctx->struct_btf ? : ctx->btf; +} + static int check_prepare_btf_string_fetch(char *typename, struct fetch_insn **pcode, struct traceprobe_parse_context *ctx) { - struct btf *btf = ctx->btf; + struct btf *btf = ctx_btf(ctx); if (!btf || !ctx->last_type) return 0; @@ -506,6 +528,15 @@ static int query_btf_context(struct traceprobe_parse_context *ctx) return 0; } +static void clear_struct_btf(struct traceprobe_parse_context *ctx) +{ + if (ctx->struct_btf) { + btf_put(ctx->struct_btf); + ctx->struct_btf = NULL; + ctx->last_struct = NULL; + } +} + static void clear_btf_context(struct traceprobe_parse_context *ctx) { if (ctx->btf) { @@ -554,22 +585,29 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type, struct fetch_insn *code = *pcode; const struct btf_member *field; u32 bitoffs, anon_offs; + bool is_struct = ctx->struct_btf != NULL; + struct btf *btf = ctx_btf(ctx); char *next; int is_ptr; s32 tid; do { - /* Outer loop for solving arrow operator ('->') */ - if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) { - trace_probe_log_err(ctx->offset, NO_PTR_STRCT); - return -EINVAL; - } - /* Convert a struct pointer type to a struct type */ - type = btf_type_skip_modifiers(ctx->btf, type->type, &tid); - if (!type) { - trace_probe_log_err(ctx->offset, BAD_BTF_TID); - return -EINVAL; + if (!is_struct) { + /* Outer loop for solving arrow operator ('->') */ + if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) { + trace_probe_log_err(ctx->offset, NO_PTR_STRCT); + return -EINVAL; + } + + /* Convert a struct pointer type to a struct type */ + type = btf_type_skip_modifiers(btf, type->type, &tid); + if (!type) { + trace_probe_log_err(ctx->offset, BAD_BTF_TID); + return -EINVAL; + } } + /* Only the first type can skip being a pointer */ + is_struct = false; bitoffs = 0; do { @@ -580,7 +618,7 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type, return is_ptr; anon_offs = 0; - field = btf_find_struct_member(ctx->btf, type, fieldname, + field = btf_find_struct_member(btf, type, fieldname, &anon_offs); if (IS_ERR(field)) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); @@ -602,7 +640,7 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type, ctx->last_bitsize = 0; } - type = btf_type_skip_modifiers(ctx->btf, field->type, &tid); + type = btf_type_skip_modifiers(btf, field->type, &tid); if (!type) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return -EINVAL; @@ -640,7 +678,7 @@ static int parse_btf_arg(char *varname, int i, is_ptr, ret; u32 tid; - if (WARN_ON_ONCE(!ctx->funcname)) + if (WARN_ON_ONCE(!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT))) return -EINVAL; is_ptr = split_next_field(varname, &field, ctx); @@ -653,6 +691,19 @@ static int parse_btf_arg(char *varname, return -EOPNOTSUPP; } + if (ctx->flags & TPARG_FL_TEVENT) { + ret = parse_trace_event(varname, code, ctx); + if (ret < 0) { + trace_probe_log_err(ctx->offset, BAD_ATTACH_ARG); + return ret; + } + /* TEVENT is only here via a typecast */ + if (WARN_ON_ONCE(ctx->struct_btf == NULL)) + return -EINVAL; + type = ctx->last_struct; + goto found_type; + } + if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) { code->op = FETCH_OP_RETVAL; /* Check whether the function return type is not void */ @@ -709,6 +760,7 @@ static int parse_btf_arg(char *varname, found: type = btf_type_skip_modifiers(ctx->btf, tid, &tid); +found_type: if (!type) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return -EINVAL; @@ -727,7 +779,7 @@ found: static const struct fetch_type *find_fetch_type_from_btf_type( struct traceprobe_parse_context *ctx) { - struct btf *btf = ctx->btf; + struct btf *btf = ctx_btf(ctx); const char *typestr = NULL; if (btf && ctx->last_type) @@ -758,7 +810,67 @@ static int parse_btf_bitfield(struct fetch_insn **pcode, return 0; } -#else +static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx) +{ + struct btf *btf = NULL; + int id; + + /* A struct_btf should only be used by a single argument */ + if (WARN_ON_ONCE(ctx->struct_btf)) { + btf_put(ctx->struct_btf); + ctx->struct_btf = NULL; + } + + id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf); + if (id < 0) + return id; + ctx->struct_btf = btf; + ctx->last_struct = btf_type_by_id(ctx->struct_btf, id); + return 0; +} + +static int handle_typecast(char *arg, struct fetch_insn **pcode, + struct fetch_insn *end, + struct traceprobe_parse_context *ctx) +{ + char *tmp; + int ret; + + /* Currently this only works for eprobes */ + if (!(ctx->flags & TPARG_FL_TEVENT)) { + trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT); + return -EINVAL; + } + + tmp = strchr(arg, ')'); + if (!tmp) { + trace_probe_log_err(ctx->offset + strlen(arg), + DEREF_OPEN_BRACE); + return -EINVAL; + } + *tmp = '\0'; + ret = query_btf_struct(arg + 1, ctx); + *tmp = ')'; + + if (ret < 0) { + trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT); + return -EINVAL; + } + + tmp++; + + ctx->offset += tmp - arg; + ret = parse_btf_arg(tmp, pcode, end, ctx); + return ret; +} + +#else /* !CONFIG_PROBE_EVENTS_BTF_ARGS */ + +static void clear_struct_btf(struct traceprobe_parse_context *ctx) +{ + ctx->struct_btf = NULL; +} + static void clear_btf_context(struct traceprobe_parse_context *ctx) { ctx->btf = NULL; @@ -794,7 +906,15 @@ static int check_prepare_btf_string_fetch(char *typename, return 0; } -#endif +static int handle_typecast(char *arg, struct fetch_insn **pcode, + struct fetch_insn *end, + struct traceprobe_parse_context *ctx) +{ + trace_probe_log_err(ctx->offset, NOSUP_BTFARG); + return -EOPNOTSUPP; +} + +#endif /* CONFIG_PROBE_EVENTS_BTF_ARGS */ #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API @@ -838,15 +958,10 @@ static int __store_entry_arg(struct trace_probe *tp, int argnum) int i, offset, last_offset = 0; if (!earg) { - earg = kzalloc_obj(*tp->entry_arg); + earg = kzalloc_flex(*earg, code, 2 * tp->nr_args + 1); if (!earg) return -ENOMEM; earg->size = 2 * tp->nr_args + 1; - earg->code = kzalloc_objs(struct fetch_insn, earg->size); - if (!earg->code) { - kfree(earg); - return -ENOMEM; - } /* Fill the code buffer with 'end' to simplify it */ for (i = 0; i < earg->size; i++) earg->code[i].op = FETCH_OP_END; @@ -953,16 +1068,9 @@ static int parse_probe_vars(char *orig_arg, const struct fetch_type *t, int len; if (ctx->flags & TPARG_FL_TEVENT) { - if (code->data) - return -EFAULT; - ret = parse_trace_event_arg(arg, code, ctx); - if (!ret) - return 0; - if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { - code->op = FETCH_OP_COMM; - return 0; - } - goto inval; + if (parse_trace_event(arg, code, ctx) < 0) + goto inval; + return 0; } if (str_has_prefix(arg, "retval")) { @@ -1229,6 +1337,9 @@ parse_probe_arg(char *arg, const struct fetch_type *type, code->op = FETCH_OP_IMM; } break; + case '(': + ret = handle_typecast(arg, pcode, end, ctx); + break; default: if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */ if (!tparg_is_function_entry(ctx->flags) && @@ -1561,6 +1672,9 @@ fail: } kfree(tmp); + /* struct_btf should not be passed to other arguments */ + clear_struct_btf(ctx); + return ret; } @@ -2049,7 +2163,6 @@ void trace_probe_cleanup(struct trace_probe *tp) traceprobe_free_probe_arg(&tp->args[i]); if (tp->entry_arg) { - kfree(tp->entry_arg->code); kfree(tp->entry_arg); tp->entry_arg = NULL; } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 262d870..15758cc 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -238,8 +238,8 @@ struct probe_arg { }; struct probe_entry_arg { - struct fetch_insn *code; unsigned int size; /* The entry data size */ + struct fetch_insn code[] __counted_by(size); }; struct trace_uprobe_filter { @@ -422,7 +422,9 @@ struct traceprobe_parse_context { const struct btf_param *params; /* Parameter of the function */ s32 nr_params; /* The number of the parameters */ struct btf *btf; /* The BTF to be used */ + struct btf *struct_btf; /* The BTF to be used for structs */ const struct btf_type *last_type; /* Saved type */ + const struct btf_type *last_struct; /* Saved structure */ u32 last_bitoffs; /* Saved bitoffs */ u32 last_bitsize; /* Saved bitsize */ struct trace_probe *tp; @@ -563,7 +565,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"),\ C(TOO_MANY_ARGS, "Too many arguments are specified"), \ C(TOO_MANY_EARGS, "Too many entry arguments specified"), \ - C(EVENT_TOO_BIG, "Event too big (too many fields?)"), + C(EVENT_TOO_BIG, "Event too big (too many fields?)"), \ + C(TYPECAST_NOT_EVENT, "Typecasts are only for eprobe fields"), #undef C #define C(a, b) TP_ERR_##a diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 2cabf8a..c274346 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -912,7 +912,7 @@ static int uprobe_buffer_enable(void) { int ret = 0; - BUG_ON(!mutex_is_locked(&event_mutex)); + lockdep_assert_held(&event_mutex); if (uprobe_buffer_refcnt++ == 0) { ret = uprobe_buffer_init(); @@ -927,7 +927,7 @@ static void uprobe_buffer_disable(void) { int cpu; - BUG_ON(!mutex_is_locked(&event_mutex)); + lockdep_assert_held(&event_mutex); if (--uprobe_buffer_refcnt == 0) { for_each_possible_cpu(cpu) @@ -979,6 +979,7 @@ static struct uprobe_cpu_buffer *prepare_uprobe_buffer(struct trace_uprobe *tu, ucb = uprobe_buffer_get(); ucb->dsize = tu->tp.size + dsize; + BUILD_BUG_ON(MAX_UCB_BUFFER_SIZE < MAX_PROBE_EVENT_SIZE); if (WARN_ON_ONCE(ucb->dsize > MAX_UCB_BUFFER_SIZE)) { ucb->dsize = MAX_UCB_BUFFER_SIZE; dsize = MAX_UCB_BUFFER_SIZE - tu->tp.size;