* [PATCH v2 1/2] tracing/probes: Add symstr type for dynamic events
2022-10-26 15:48 [PATCH v2 0/2] tracing/probes: Add 'symstr' type for probes Masami Hiramatsu (Google)
@ 2022-10-26 15:48 ` Masami Hiramatsu (Google)
2022-10-26 15:48 ` [PATCH v2 2/2] tracing/probes: Reject symbol/symstr type for uprobe Masami Hiramatsu (Google)
1 sibling, 0 replies; 3+ messages in thread
From: Masami Hiramatsu (Google) @ 2022-10-26 15:48 UTC (permalink / raw)
To: LKML; +Cc: Steven Rostedt, Linux Trace Kernel, Masami Hiramatsu,
Primiano Tucci
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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) <mhiramat@kernel.org>
---
Changes in v2:
- Remove redundant strlen().
---
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]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
"\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
"\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
- "\t <type>\\[<array-size>\\]\n"
+ "\t symstr, <type>\\[<array-size>\\]\n"
#ifdef CONFIG_HIST_TRIGGERS
"\t field: <stype> <name>;\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..5cea672243f6 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 ret + 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;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v2 2/2] tracing/probes: Reject symbol/symstr type for uprobe
2022-10-26 15:48 [PATCH v2 0/2] tracing/probes: Add 'symstr' type for probes Masami Hiramatsu (Google)
2022-10-26 15:48 ` [PATCH v2 1/2] tracing/probes: Add symstr type for dynamic events Masami Hiramatsu (Google)
@ 2022-10-26 15:48 ` Masami Hiramatsu (Google)
1 sibling, 0 replies; 3+ messages in thread
From: Masami Hiramatsu (Google) @ 2022-10-26 15:48 UTC (permalink / raw)
To: LKML; +Cc: Steven Rostedt, Linux Trace Kernel, Masami Hiramatsu,
Primiano Tucci
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Since uprobe's argument must contain the user-space data, that
should not be converted to kernel symbols. Reject if user
specifies these types on uprobe events. e.g.
/sys/kernel/debug/tracing # echo 'p /bin/sh:10 %ax:symbol' >> uprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # echo 'p /bin/sh:10 %ax:symstr' >> uprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # cat error_log
[ 1783.134883] trace_uprobe: error: Unknown type is specified
Command: p /bin/sh:10 %ax:symbol
^
[ 1792.201120] trace_uprobe: error: Unknown type is specified
Command: p /bin/sh:10 %ax:symstr
^
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Fixes indentation.
---
kernel/trace/trace_probe.c | 21 ++++++++++++--------
kernel/trace/trace_probe.h | 3 ++-
kernel/trace/trace_uprobe.c | 3 ++-
.../ftrace/test.d/kprobe/uprobe_syntax_errors.tc | 5 +++++
4 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index dfec4af857b4..960bb7693a84 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -100,10 +100,15 @@ static const struct fetch_type probe_fetch_types[] = {
ASSIGN_FETCH_TYPE_END
};
-static const struct fetch_type *find_fetch_type(const char *type)
+static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
{
int i;
+ /* Reject the symbol/symstr for uprobes */
+ if (type && (flags & TPARG_FL_USER) &&
+ (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
+ return NULL;
+
if (!type)
type = DEFAULT_FETCH_TYPE_STR;
@@ -121,13 +126,13 @@ static const struct fetch_type *find_fetch_type(const char *type)
switch (bs) {
case 8:
- return find_fetch_type("u8");
+ return find_fetch_type("u8", flags);
case 16:
- return find_fetch_type("u16");
+ return find_fetch_type("u16", flags);
case 32:
- return find_fetch_type("u32");
+ return find_fetch_type("u32", flags);
case 64:
- return find_fetch_type("u64");
+ return find_fetch_type("u64", flags);
default:
goto fail;
}
@@ -480,7 +485,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
DEREF_OPEN_BRACE);
return -EINVAL;
} else {
- const struct fetch_type *t2 = find_fetch_type(NULL);
+ const struct fetch_type *t2 = find_fetch_type(NULL, flags);
*tmp = '\0';
ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
@@ -632,9 +637,9 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
/* The type of $comm must be "string", and not an array. */
if (parg->count || (t && strcmp(t, "string")))
goto out;
- parg->type = find_fetch_type("string");
+ parg->type = find_fetch_type("string", flags);
} else
- parg->type = find_fetch_type(t);
+ parg->type = find_fetch_type(t, flags);
if (!parg->type) {
trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
goto out;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 0838b74f403b..23acfd1c3812 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -358,7 +358,8 @@ int trace_probe_create(const char *raw_command, int (*createfn)(int, const char
#define TPARG_FL_KERNEL BIT(1)
#define TPARG_FL_FENTRY BIT(2)
#define TPARG_FL_TPOINT BIT(3)
-#define TPARG_FL_MASK GENMASK(3, 0)
+#define TPARG_FL_USER BIT(4)
+#define TPARG_FL_MASK GENMASK(4, 0)
extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
const char *argv, unsigned int flags);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index fb58e86dd117..8d64b6553aed 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -691,7 +691,8 @@ static int __trace_uprobe_create(int argc, const char **argv)
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
trace_probe_log_set_index(i + 2);
ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
- is_return ? TPARG_FL_RETURN : 0);
+ (is_return ? TPARG_FL_RETURN : 0) |
+ TPARG_FL_USER);
if (ret)
goto error;
}
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
index f5e3f9e4a01f..c817158b99db 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
@@ -23,4 +23,9 @@ check_error 'p /bin/sh:10^%hoge' # BAD_ADDR_SUFFIX
check_error 'p /bin/sh:10(10)^%return' # BAD_REFCNT_SUFFIX
fi
+# symstr is not supported by uprobe
+if grep -q ".*symstr.*" README; then
+check_error 'p /bin/sh:10 $stack0:^symstr' # BAD_TYPE
+fi
+
exit 0
^ permalink raw reply related [flat|nested] 3+ messages in thread