diff options
Diffstat (limited to 'kernel/trace/trace_probe.c')
| -rw-r--r-- | kernel/trace/trace_probe.c | 79 |
1 files changed, 45 insertions, 34 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 16a5e368e7b7..2eeecb6c95ee 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -770,6 +770,10 @@ static int check_prepare_btf_string_fetch(char *typename, #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API +/* + * Add the entry code to store the 'argnum'th parameter and return the offset + * in the entry data buffer where the data will be stored. + */ static int __store_entry_arg(struct trace_probe *tp, int argnum) { struct probe_entry_arg *earg = tp->entry_arg; @@ -793,6 +797,20 @@ static int __store_entry_arg(struct trace_probe *tp, int argnum) tp->entry_arg = earg; } + /* + * The entry code array is repeating the pair of + * [FETCH_OP_ARG(argnum)][FETCH_OP_ST_EDATA(offset of entry data buffer)] + * and the rest of entries are filled with [FETCH_OP_END]. + * + * To reduce the redundant function parameter fetching, we scan the entry + * code array to find the FETCH_OP_ARG which already fetches the 'argnum' + * parameter. If it doesn't match, update 'offset' to find the last + * offset. + * If we find the FETCH_OP_END without matching FETCH_OP_ARG entry, we + * will save the entry with FETCH_OP_ARG and FETCH_OP_ST_EDATA, and + * return data offset so that caller can find the data offset in the entry + * data buffer. + */ offset = 0; for (i = 0; i < earg->size - 1; i++) { switch (earg->code[i].op) { @@ -826,6 +844,16 @@ int traceprobe_get_entry_data_size(struct trace_probe *tp) if (!earg) return 0; + /* + * earg->code[] array has an operation sequence which is run in + * the entry handler. + * The sequence stopped by FETCH_OP_END and each data stored in + * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA + * stores the data at the data buffer + its offset, and all data are + * "unsigned long" size. The offset must be increased when a data is + * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the + * code array. + */ for (i = 0; i < earg->size; i++) { switch (earg->code[i].op) { case FETCH_OP_END: @@ -1409,7 +1437,7 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, struct traceprobe_parse_context *ctx) { struct fetch_insn *code, *tmp = NULL; - char *type, *arg; + char *type, *arg __free(kfree) = NULL; int ret, len; len = strlen(argv); @@ -1426,22 +1454,16 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, return -ENOMEM; parg->comm = kstrdup(arg, GFP_KERNEL); - if (!parg->comm) { - ret = -ENOMEM; - goto out; - } + if (!parg->comm) + return -ENOMEM; type = parse_probe_arg_type(arg, parg, ctx); - if (IS_ERR(type)) { - ret = PTR_ERR(type); - goto out; - } + if (IS_ERR(type)) + return PTR_ERR(type); code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL); - if (!code) { - ret = -ENOMEM; - goto out; - } + if (!code) + return -ENOMEM; code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; ctx->last_type = NULL; @@ -1497,8 +1519,6 @@ fail: kfree(code->data); } kfree(tmp); -out: - kfree(arg); return ret; } @@ -1668,7 +1688,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[], { const struct btf_param *params = NULL; int i, j, n, used, ret, args_idx = -1; - const char **new_argv = NULL; + const char **new_argv __free(kfree) = NULL; ret = argv_has_var_arg(argc, argv, &args_idx, ctx); if (ret < 0) @@ -1707,7 +1727,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[], ret = sprint_nth_btf_arg(n, "", buf + used, bufsize - used, ctx); if (ret < 0) - goto error; + return ERR_PTR(ret); new_argv[j++] = buf + used; used += ret + 1; @@ -1721,25 +1741,20 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[], n = simple_strtoul(argv[i] + 4, &type, 10); if (type && !(*type == ':' || *type == '\0')) { trace_probe_log_err(0, BAD_VAR); - ret = -ENOENT; - goto error; + return ERR_PTR(-ENOENT); } /* Note: $argN starts from $arg1 */ ret = sprint_nth_btf_arg(n - 1, type, buf + used, bufsize - used, ctx); if (ret < 0) - goto error; + return ERR_PTR(ret); new_argv[j++] = buf + used; used += ret + 1; } else new_argv[j++] = argv[i]; } - return new_argv; - -error: - kfree(new_argv); - return ERR_PTR(ret); + return_ptr(new_argv); } /* @buf: *buf must be equal to NULL. Caller must to free *buf */ @@ -1747,14 +1762,14 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf) { int i, used, ret; const int bufsize = MAX_DENTRY_ARGS_LEN; - char *tmpbuf = NULL; + char *tmpbuf __free(kfree) = NULL; if (*buf) return -EINVAL; used = 0; for (i = 0; i < argc; i++) { - char *tmp; + char *tmp __free(kfree) = NULL; char *equal; size_t arg_len; @@ -1769,7 +1784,7 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf) tmp = kstrdup(argv[i], GFP_KERNEL); if (!tmp) - goto nomem; + return -ENOMEM; equal = strchr(tmp, '='); if (equal) @@ -1790,18 +1805,14 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf) offsetof(struct file, f_path.dentry), equal ? equal + 1 : tmp); - kfree(tmp); if (ret >= bufsize - used) - goto nomem; + return -ENOMEM; argv[i] = tmpbuf + used; used += ret + 1; } - *buf = tmpbuf; + *buf = no_free_ptr(tmpbuf); return 0; -nomem: - kfree(tmpbuf); - return -ENOMEM; } void traceprobe_finish_parse(struct traceprobe_parse_context *ctx) |