From patchwork Sat Oct 22 06:38:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13015826 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03C67C433FE for ; Sat, 22 Oct 2022 06:39:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230027AbiJVGjA (ORCPT ); Sat, 22 Oct 2022 02:39:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230122AbiJVGi6 (ORCPT ); Sat, 22 Oct 2022 02:38:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1797255C43; Fri, 21 Oct 2022 23:38:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7C7A86097D; Sat, 22 Oct 2022 06:38:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2F26C433D7; Sat, 22 Oct 2022 06:38:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666420733; bh=WGd7MguF1z0D6oWt6GAI3yTYToO9aCCfZ4K/PbFF5kE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cqk2LUkwk6JEdi5QNc1slgy3b/JaoNbFQgmRR+qG4ZjToKCVTh+f5xM3NhxFlYGiY uwfDV8SdmPQDmGgDo3Mek0ZeY6BeWsw/uyBT2VTmS7x1fiK7pkBb7z67Wjsl/c1Ef+ jUgL966wiQ6/zwvyYMyZfXBHNxxo9cDmZflLvdh8pzRhsmxQmfz2x/SJynbJdEeZOM V+jKIsnv7p3PiefCBxa+Y6Xz7ov1Fa5OrSBuzj61d5EyvqN3Nn7tIT3VQhDeuZ+Elx 5VzAz0pTgRPyui1tilJ1aO3OFeS2eDLfm1zUGqekhr/iQSy6v1Px5w/kCBnsIIr4ir /DyvSacpJzb8A== From: "Masami Hiramatsu (Google)" To: LKML Cc: Steven Rostedt , Linux Trace Kernel , Masami Hiramatsu , Primiano Tucci Subject: [PATCH 1/2] tracing/probes: Add symstr type for dynamic events Date: Sat, 22 Oct 2022 15:38:50 +0900 Message-Id: <166642073074.718058.9841757174640040227.stgit@mhiramat.roam.corp.google.com> X-Mailer: git-send-email 2.38.0.135.g90850a2211-goog In-Reply-To: <166642072204.718058.1479401089273534841.stgit@mhiramat.roam.corp.google.com> References: <166642072204.718058.1479401089273534841.stgit@mhiramat.roam.corp.google.com> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Add 'symstr' type for storing the kernel symbol as a string data instead of the symbol address. This allows us to filter the events by wildcard symbol name. e.g. # echo 'e:wqfunc workqueue.workqueue_execute_start symname=$function:symstr' >> dynamic_events # cat events/eprobes/wqfunc/format name: wqfunc ID: 2110 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:__data_loc char[] symname; offset:8; size:4; signed:1; print fmt: " symname=\"%s\"", __get_str(symname) Note that there is already 'symbol' type which just change the print format (so it still stores the symbol address in the tracing ring buffer.) On the other hand, 'symstr' type stores the actual "symbol+offset/size" data as a string. Signed-off-by: Masami Hiramatsu (Google) --- Documentation/trace/kprobetrace.rst | 8 ++++-- kernel/trace/trace.c | 2 + kernel/trace/trace_probe.c | 44 ++++++++++++++++++++++----------- kernel/trace/trace_probe.h | 16 ++++++++---- kernel/trace/trace_probe_tmpl.h | 47 +++++++++++++++++++++++++++++++++-- 5 files changed, 91 insertions(+), 26 deletions(-) diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index 4274cc6a2f94..08a2a6a3782f 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -58,8 +58,8 @@ Synopsis of kprobe_events NAME=FETCHARG : Set NAME as the argument name of FETCHARG. FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types - (x8/x16/x32/x64), "string", "ustring" and bitfield - are supported. + (x8/x16/x32/x64), "string", "ustring", "symbol", "symstr" + and bitfield are supported. (\*1) only for the probe on function entry (offs == 0). (\*2) only for return probe. @@ -96,6 +96,10 @@ offset, and container-size (usually 32). The syntax is:: Symbol type('symbol') is an alias of u32 or u64 type (depends on BITS_PER_LONG) which shows given pointer in "symbol+offset" style. +On the other hand, symbol-string type ('symstr') converts the given address to +"symbol+offset/symbolsize" style and stores it as a null-terminated string. +With 'symstr' type, you can filter the event with wildcard pattern of the +symbols, and you don't need to solve symbol name by yourself. For $comm, the default type is "string"; any other type is invalid. .. _user_mem_access: diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 47a44b055a1d..80aae336cc19 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5608,7 +5608,7 @@ static const char readme_msg[] = "\t +|-[u](), \\imm-value, \\\"imm-string\"\n" "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n" "\t b@/, ustring,\n" - "\t \\[\\]\n" + "\t symstr, \\[\\]\n" #ifdef CONFIG_HIST_TRIGGERS "\t field: ;\n" "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n" diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 36dff277de46..dfec4af857b4 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -76,9 +76,11 @@ const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\""; /* Fetch type information table */ static const struct fetch_type probe_fetch_types[] = { /* Special types */ - __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, + __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1, "__data_loc char[]"), - __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, + __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1, + "__data_loc char[]"), + __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1, "__data_loc char[]"), /* Basic types */ ASSIGN_FETCH_TYPE(u8, u8, 0), @@ -662,16 +664,26 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, ret = -EINVAL; /* Store operation */ - if (!strcmp(parg->type->name, "string") || - !strcmp(parg->type->name, "ustring")) { - if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF && - code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM && - code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) { - trace_probe_log_err(offset + (t ? (t - arg) : 0), - BAD_STRING); - goto fail; + if (parg->type->is_string) { + if (!strcmp(parg->type->name, "symstr")) { + if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK && + code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG && + code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) { + trace_probe_log_err(offset + (t ? (t - arg) : 0), + BAD_SYMSTRING); + goto fail; + } + } else { + if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF && + code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM && + code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) { + trace_probe_log_err(offset + (t ? (t - arg) : 0), + BAD_STRING); + goto fail; + } } - if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || + if (!strcmp(parg->type->name, "symstr") || + (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG || parg->count) { /* @@ -679,6 +691,8 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, * must be kept, and if parg->count != 0, this is an * array of string pointers instead of string address * itself. + * For the symstr, it doesn't need to dereference, thus + * it just get the value. */ code++; if (code->op != FETCH_OP_NOP) { @@ -690,6 +704,8 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, if (!strcmp(parg->type->name, "ustring") || code->op == FETCH_OP_UDEREF) code->op = FETCH_OP_ST_USTRING; + else if (!strcmp(parg->type->name, "symstr")) + code->op = FETCH_OP_ST_SYMSTR; else code->op = FETCH_OP_ST_STRING; code->size = parg->type->size; @@ -919,8 +935,7 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, for (i = 0; i < tp->nr_args; i++) { parg = tp->args + i; if (parg->count) { - if ((strcmp(parg->type->name, "string") == 0) || - (strcmp(parg->type->name, "ustring") == 0)) + if (parg->type->is_string) fmt = ", __get_str(%s[%d])"; else fmt = ", REC->%s[%d]"; @@ -928,8 +943,7 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, pos += snprintf(buf + pos, LEN_OR_ZERO, fmt, parg->name, j); } else { - if ((strcmp(parg->type->name, "string") == 0) || - (strcmp(parg->type->name, "ustring") == 0)) + if (parg->type->is_string) fmt = ", __get_str(%s)"; else fmt = ", REC->%s"; diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index de38f1c03776..0838b74f403b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -98,6 +98,7 @@ enum fetch_op { FETCH_OP_ST_UMEM, /* Mem: .offset, .size */ FETCH_OP_ST_STRING, /* String: .offset, .size */ FETCH_OP_ST_USTRING, /* User String: .offset, .size */ + FETCH_OP_ST_SYMSTR, /* Kernel Symbol String: .offset, .size */ // Stage 4 (modify) op FETCH_OP_MOD_BF, /* Bitfield: .basesize, .lshift, .rshift */ // Stage 5 (loop) op @@ -133,7 +134,8 @@ struct fetch_insn { struct fetch_type { const char *name; /* Name of type */ size_t size; /* Byte size of type */ - int is_signed; /* Signed flag */ + bool is_signed; /* Signed flag */ + bool is_string; /* String flag */ print_type_func_t print; /* Print functions */ const char *fmt; /* Format string */ const char *fmttype; /* Name in format file */ @@ -177,16 +179,19 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(symbol); #define _ADDR_FETCH_TYPE(t) __ADDR_FETCH_TYPE(t) #define ADDR_FETCH_TYPE _ADDR_FETCH_TYPE(BITS_PER_LONG) -#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \ - {.name = _name, \ +#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, str, _fmttype) \ + {.name = _name, \ .size = _size, \ - .is_signed = sign, \ + .is_signed = (bool)sign, \ + .is_string = (bool)str, \ .print = PRINT_TYPE_FUNC_NAME(ptype), \ .fmt = PRINT_TYPE_FMT_NAME(ptype), \ .fmttype = _fmttype, \ } + +/* Non string types can use these macros */ #define _ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \ - __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, #_fmttype) + __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, 0, #_fmttype) #define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \ _ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, ptype) @@ -431,6 +436,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(ARRAY_TOO_BIG, "Array number is too big"), \ C(BAD_TYPE, "Unknown type is specified"), \ C(BAD_STRING, "String accepts only memory argument"), \ + C(BAD_SYMSTRING, "Symbol String doesn't accept data/userdata"), \ C(BAD_BITFIELD, "Invalid bitfield"), \ C(ARG_NAME_TOO_LONG, "Argument name is too long"), \ C(NO_ARG_NAME, "Argument name is not specified"), \ diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index b3bdb8ddb862..d57a3143929a 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -67,6 +67,37 @@ probe_mem_read(void *dest, void *src, size_t size); static nokprobe_inline int probe_mem_read_user(void *dest, void *src, size_t size); +static nokprobe_inline int +fetch_store_symstrlen(unsigned long addr) +{ + char namebuf[KSYM_SYMBOL_LEN]; + int ret; + + ret = sprint_symbol(namebuf, addr); + if (ret < 0) + return 0; + + return strlen(namebuf) + 1; +} + +/* + * Fetch a null-terminated symbol string + offset. Caller MUST set *(u32 *)buf + * with max length and relative data location. + */ +static nokprobe_inline int +fetch_store_symstring(unsigned long addr, void *dest, void *base) +{ + int maxlen = get_loc_len(*(u32 *)dest); + void *__dest; + + if (unlikely(!maxlen)) + return -ENOMEM; + + __dest = get_loc_data(dest, base); + + return sprint_symbol(__dest, addr); +} + /* From the 2nd stage, routine is same */ static nokprobe_inline int process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, @@ -99,16 +130,22 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, stage3: /* 3rd stage: store value to buffer */ if (unlikely(!dest)) { - if (code->op == FETCH_OP_ST_STRING) { + switch (code->op) { + case FETCH_OP_ST_STRING: ret = fetch_store_strlen(val + code->offset); code++; goto array; - } else if (code->op == FETCH_OP_ST_USTRING) { + case FETCH_OP_ST_USTRING: ret += fetch_store_strlen_user(val + code->offset); code++; goto array; - } else + case FETCH_OP_ST_SYMSTR: + ret += fetch_store_symstrlen(val + code->offset); + code++; + goto array; + default: return -EILSEQ; + } } switch (code->op) { @@ -129,6 +166,10 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, loc = *(u32 *)dest; ret = fetch_store_string_user(val + code->offset, dest, base); break; + case FETCH_OP_ST_SYMSTR: + loc = *(u32 *)dest; + ret = fetch_store_symstring(val + code->offset, dest, base); + break; default: return -EILSEQ; }