[PATCH v5 0/8] support '%pd' and '%pD' for print file name

[PATCH v5 0/8] support '%pd' and '%pD' for print file name

[Ye Bin]

During fault locating, the file name needs to be printed based on the
dentry/file address. The offset needs to be calculated each time, which
is troublesome. Similar to printk, kprobe supports printing file names
for dentry/file addresses.

Diff v5 vs v4:
1. Use glob_match() instead of str_has_suffix(), so remove the first patch;
2. Allocate buffer from heap for expand dentry;
3. Support "%pd/%pD" print type for fprobe;
4. Use $arg1 instead of origin register in test case;
5. Add test case for fprobe;

Diff v4 vs v3:
1. Use "argv[i][idx + 3] == 'd'" instead of "argv[i][strlen(argv[i]) - 1] == 'd'"
to judge print format in PATCH[4/7];

Diff v3 vs v2:
1. Return the index of where the suffix was found in str_has_suffix();

Diff v2 vs v1:
1. Use "%pd/%pD" print format instead of "pd/pD" print format;
2. Add "%pd/%pD" in README;
3. Expand "%pd/%pD" argument before parameter parsing;
4. Add more detail information in ftrace documentation;
5. Add test cases for new print format in selftests/ftrace;

Ye Bin (8):
  tracing/probes: add traceprobe_expand_dentry_args() helper
  tracing/probes: support '%pd' type for print struct dentry's name
  tracing/probes: support '%pD' type for print struct file's name
  tracing/probes: support '%pd/%pD' type for fprobe
  tracing: add new type "%pd/%pD" in readme_msg[]
  Documentation: tracing: add new type '%pd' and '%pD' for kprobe
  selftests/ftrace: add kprobe test cases for VFS type "%pd" and "%pD"
  selftests/ftrace: add fprobe test cases for VFS type "%pd" and "%pD"

 Documentation/trace/kprobetrace.rst           |  8 ++-
 kernel/trace/trace.c                          |  2 +-
 kernel/trace/trace_fprobe.c                   |  6 ++
 kernel/trace/trace_kprobe.c                   |  6 ++
 kernel/trace/trace_probe.c                    | 63 +++++++++++++++++++
 kernel/trace/trace_probe.h                    |  2 +
 .../ftrace/test.d/dynevent/fprobe_args_vfs.tc | 40 ++++++++++++
 .../ftrace/test.d/kprobe/kprobe_args_vfs.tc   | 43 +++++++++++++
 8 files changed, 167 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_args_vfs.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc

-- 
2.31.1

[PATCH v5 1/8] tracing/probes: add traceprobe_expand_dentry_args() helper

[Ye Bin]

Add traceprobe_expand_dentry_args() to expand dentry args. this API is
prepare to support "%pd" print format for kprobe.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 kernel/trace/trace_probe.c | 50 ++++++++++++++++++++++++++++++++++++++
 kernel/trace/trace_probe.h |  2 ++
 2 files changed, 52 insertions(+)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 4dc74d73fc1d..0c1caf0f474a 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1565,6 +1565,56 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
 	return ERR_PTR(ret);
 }
 
+/* @buf: *buf must be equal to NULL. Caller must to free *buf */
+int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
+{
+	int i, used, ret;
+	int bufsize = MAX_DENTRY_ARGS_LEN;
+	char *tmpbuf = NULL;
+
+	if (*buf)
+		return -EINVAL;
+
+	used = 0;
+	for (i = 0; i < argc; i++) {
+		if (glob_match("*:%pd", argv[i])) {
+			char *tmp;
+			char *equal;
+
+			if (!tmpbuf) {
+				tmpbuf = kmalloc(bufsize, GFP_KERNEL);
+				if (!tmpbuf)
+					return -ENOMEM;
+			}
+
+			tmp = kstrdup(argv[i], GFP_KERNEL);
+			if (!tmp)
+				goto nomem;
+
+			equal = strchr(tmp, '=');
+			if (equal)
+				*equal = '\0';
+			tmp[strlen(argv[i]) - 4] = '\0';
+			ret = snprintf(tmpbuf + used, bufsize - used,
+				       "%s%s+0x0(+0x%zx(%s)):string",
+				       equal ? tmp : "", equal ? "=" : "",
+				       offsetof(struct dentry, d_name.name),
+				       equal ? equal + 1 : tmp);
+			kfree(tmp);
+			if (ret >= bufsize - used)
+				goto nomem;
+			argv[i] = tmpbuf + used;
+			used += ret + 1;
+		}
+	}
+
+	*buf = tmpbuf;
+	return 0;
+nomem:
+	kfree(tmpbuf);
+	return -ENOMEM;
+}
+
 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
 {
 	clear_btf_context(ctx);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 850d9ecb6765..5800513439f3 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -34,6 +34,7 @@
 #define MAX_ARRAY_LEN		64
 #define MAX_ARG_NAME_LEN	32
 #define MAX_BTF_ARGS_LEN	128
+#define MAX_DENTRY_ARGS_LEN	256
 #define MAX_STRING_SIZE		PATH_MAX
 #define MAX_ARG_BUF_LEN		(MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
 
@@ -402,6 +403,7 @@ extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
 					 int *new_argc, char *buf, int bufsize,
 					 struct traceprobe_parse_context *ctx);
+extern int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf);
 
 extern int traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
-- 
2.31.1

[PATCH v5 2/8] tracing/probes: support '%pd' type for print struct dentry's name

[Ye Bin]

Similar to '%pd' for printk, use '%pd' for print struct dentry's name.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 kernel/trace/trace_kprobe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index c4c6e0e0068b..7cbb43740b4f 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -779,6 +779,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 	char buf[MAX_EVENT_NAME_LEN];
 	char gbuf[MAX_EVENT_NAME_LEN];
 	char abuf[MAX_BTF_ARGS_LEN];
+	char *dbuf = NULL;
 	struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 
 	switch (argv[0][0]) {
@@ -930,6 +931,10 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 		argv = new_argv;
 	}
 
+	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
+	if (ret)
+		goto out;
+
 	/* setup a probe */
 	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 				argc, is_return);
@@ -971,6 +976,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 	trace_probe_log_clear();
 	kfree(new_argv);
 	kfree(symbol);
+	kfree(dbuf);
 	return ret;
 
 parse_error:
-- 
2.31.1

[PATCH v5 3/8] tracing/probes: support '%pD' type for print struct file's name

[Ye Bin]

Similar to '%pD' for printk, use '%pD' for print struct file's name.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 kernel/trace/trace_probe.c | 57 +++++++++++++++++++++++---------------
 1 file changed, 35 insertions(+), 22 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 0c1caf0f474a..5ac7b0193dd8 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -12,6 +12,7 @@
 #define pr_fmt(fmt)	"trace_probe: " fmt
 
 #include <linux/bpf.h>
+#include <linux/fs.h>
 #include "trace_btf.h"
 
 #include "trace_probe.h"
@@ -1577,35 +1578,47 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
 
 	used = 0;
 	for (i = 0; i < argc; i++) {
-		if (glob_match("*:%pd", argv[i])) {
-			char *tmp;
-			char *equal;
-
-			if (!tmpbuf) {
-				tmpbuf = kmalloc(bufsize, GFP_KERNEL);
-				if (!tmpbuf)
-					return -ENOMEM;
-			}
+		char *tmp;
+		char *equal;
+		size_t arg_len;
 
-			tmp = kstrdup(argv[i], GFP_KERNEL);
-			if (!tmp)
-				goto nomem;
+		if (!glob_match("*:%p[dD]", argv[i]))
+			continue;
 
-			equal = strchr(tmp, '=');
-			if (equal)
-				*equal = '\0';
-			tmp[strlen(argv[i]) - 4] = '\0';
+		if (!tmpbuf) {
+			tmpbuf = kmalloc(bufsize, GFP_KERNEL);
+			if (!tmpbuf)
+				return -ENOMEM;
+		}
+
+		tmp = kstrdup(argv[i], GFP_KERNEL);
+		if (!tmp)
+			goto nomem;
+
+		equal = strchr(tmp, '=');
+		if (equal)
+			*equal = '\0';
+		arg_len = strlen(argv[i]);
+		tmp[arg_len - 4] = '\0';
+		if (argv[i][arg_len - 1] == 'd')
 			ret = snprintf(tmpbuf + used, bufsize - used,
 				       "%s%s+0x0(+0x%zx(%s)):string",
 				       equal ? tmp : "", equal ? "=" : "",
 				       offsetof(struct dentry, d_name.name),
 				       equal ? equal + 1 : tmp);
-			kfree(tmp);
-			if (ret >= bufsize - used)
-				goto nomem;
-			argv[i] = tmpbuf + used;
-			used += ret + 1;
-		}
+		else
+			ret = snprintf(tmpbuf + used, bufsize - used,
+				       "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
+				       equal ? tmp : "", equal ? "=" : "",
+				       offsetof(struct dentry, d_name.name),
+				       offsetof(struct file, f_path.dentry),
+				       equal ? equal + 1 : tmp);
+
+		kfree(tmp);
+		if (ret >= bufsize - used)
+			goto nomem;
+		argv[i] = tmpbuf + used;
+		used += ret + 1;
 	}
 
 	*buf = tmpbuf;
-- 
2.31.1

[PATCH v5 4/8] tracing/probes: support '%pd/%pD' type for fprobe

[Ye Bin]

Support print type '%pd/%pD' for print dentry's or file's name.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 kernel/trace/trace_fprobe.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 7d2ddbcfa377..988d68e906ad 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -976,6 +976,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	char gbuf[MAX_EVENT_NAME_LEN];
 	char sbuf[KSYM_NAME_LEN];
 	char abuf[MAX_BTF_ARGS_LEN];
+	char *dbuf = NULL;
 	bool is_tracepoint = false;
 	struct tracepoint *tpoint = NULL;
 	struct traceprobe_parse_context ctx = {
@@ -1086,6 +1087,10 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 		argv = new_argv;
 	}
 
+	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
+	if (ret)
+		goto out;
+
 	/* setup a probe */
 	tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
 				argc, is_return);
@@ -1131,6 +1136,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	trace_probe_log_clear();
 	kfree(new_argv);
 	kfree(symbol);
+	kfree(dbuf);
 	return ret;
 
 parse_error:
-- 
2.31.1

[PATCH v5 5/8] tracing: add new type "%pd/%pD" in readme_msg[]

[Ye Bin]

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd934e9..13197d3b86bd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5745,7 +5745,7 @@ 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, char, string, symbol,\n"
 	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
-	"\t           symstr, <type>\\[<array-size>\\]\n"
+	"\t           symstr, %pd/%pD <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"
-- 
2.31.1

[PATCH v5 6/8] Documentation: tracing: add new type '%pd' and '%pD' for kprobe

[Ye Bin]

Similar to printk() '%pd' is for fetch dentry's name from struct dentry's
pointer, and '%pD' is for fetch file's name from struct file's pointer.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 Documentation/trace/kprobetrace.rst | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index bf9cecb69fc9..f13f0fc11251 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -58,8 +58,9 @@ 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), "char", "string", "ustring", "symbol", "symstr"
-                  and bitfield are supported.
+		  (x8/x16/x32/x64), VFS layer common type(%pd/%pD), "char",
+                  "string", "ustring", "symbol", "symstr" and bitfield are
+                  supported.
 
   (\*1) only for the probe on function entry (offs == 0). Note, this argument access
         is best effort, because depending on the argument type, it may be passed on
@@ -113,6 +114,9 @@ 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.
 
+VFS layer common type(%pd/%pD) is a special type, which fetches dentry's or
+file's name from struct dentry's address or struct file's address.
+
 .. _user_mem_access:
 
 User Memory Access
-- 
2.31.1

[PATCH v5 7/8] selftests/ftrace: add kprobe test cases for VFS type "%pd" and "%pD"

[Ye Bin]

This patch adds test cases for new print format type "%pd/%pD".The test cases
test the following items:
1. Test README if add "%pd/%pD" type;
2. Test "%pd" type for dput();
3. Test "%pD" type for vfs_read();

This test case require enable CONFIG_HAVE_FUNCTION_ARG_ACCESS_API configuration.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 .../ftrace/test.d/kprobe/kprobe_args_vfs.tc   | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
new file mode 100644
index 000000000000..cf0599b90f1a
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
@@ -0,0 +1,43 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe event VFS type argument
+# requires: kprobe_events
+
+: "Test argument %pd/%pD in README"
+grep -q "%pd/%pD" README
+
+: "Test argument %pd with name"
+echo 'p:testprobe dput name=$arg1:%pd' > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+grep -q "1" events/kprobes/testprobe/enable
+echo 0 > events/kprobes/testprobe/enable
+grep "dput" trace | grep -q "enable"
+echo "" > kprobe_events
+echo "" > trace
+
+: "Test argument %pd without name"
+echo 'p:testprobe dput $arg1:%pd' > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+grep -q "1" events/kprobes/testprobe/enable
+echo 0 > events/kprobes/testprobe/enable
+grep "dput" trace | grep -q "enable"
+echo "" > kprobe_events
+echo "" > trace
+
+: "Test argument %pD with name"
+echo 'p:testprobe vfs_read name=$arg1:%pD' > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+grep -q "1" events/kprobes/testprobe/enable
+echo 0 > events/kprobes/testprobe/enable
+grep "vfs_read" trace | grep -q "enable"
+echo "" > kprobe_events
+echo "" > trace
+
+: "Test argument %pD without name"
+echo 'p:testprobe vfs_read $arg1:%pD' > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+grep -q "1"  events/kprobes/testprobe/enable
+echo 0 > events/kprobes/testprobe/enable
+grep "vfs_read" trace | grep -q "enable"
+echo "" > kprobe_events
+echo "" > trace
-- 
2.31.1

[PATCH v5 8/8] selftests/ftrace: add fprobe test cases for VFS type "%pd" and "%pD"

[Ye Bin]

This patch adds fprobe test cases for new print format type "%pd/%pD".The
test cases test the following items:
1. Test "%pd" type for dput();
2. Test "%pD" type for vfs_read();

This test case require enable CONFIG_HAVE_FUNCTION_ARG_ACCESS_API configuration.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 .../ftrace/test.d/dynevent/fprobe_args_vfs.tc | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_args_vfs.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_args_vfs.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_args_vfs.tc
new file mode 100644
index 000000000000..0a5baaffc137
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_args_vfs.tc
@@ -0,0 +1,40 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Fprobe event VFS type argument
+# requires: kprobe_events
+
+: "Test argument %pd with name for fprobe"
+echo 'f:testprobe dput name=$arg1:%pd' > dynamic_events
+echo 1 > events/fprobes/testprobe/enable
+grep -q "1" events/fprobes/testprobe/enable
+echo 0 > events/fprobes/testprobe/enable
+grep "dput" trace | grep -q "enable"
+echo "" > dynamic_events
+echo "" > trace
+
+: "Test argument %pd without name for fprobe"
+echo 'f:testprobe dput $arg1:%pd' > dynamic_events
+echo 1 > events/fprobes/testprobe/enable
+grep -q "1" events/fprobes/testprobe/enable
+echo 0 > events/fprobes/testprobe/enable
+grep "dput" trace | grep -q "enable"
+echo "" > dynamic_events
+echo "" > trace
+
+: "Test argument %pD with name for fprobe"
+echo 'f:testprobe vfs_read name=$arg1:%pD' > dynamic_events
+echo 1 > events/fprobes/testprobe/enable
+grep -q "1" events/fprobes/testprobe/enable
+echo 0 > events/fprobes/testprobe/enable
+grep "vfs_read" trace | grep -q "enable"
+echo "" > dynamic_events
+echo "" > trace
+
+: "Test argument %pD without name for fprobe"
+echo 'f:testprobe vfs_read $arg1:%pD' > dynamic_events
+echo 1 > events/fprobes/testprobe/enable
+grep -q "1"  events/fprobes/testprobe/enable
+echo 0 > events/fprobes/testprobe/enable
+grep "vfs_read" trace | grep -q "enable"
+echo "" > dynamic_events
+echo "" > trace
-- 
2.31.1

Re: [PATCH v5 1/8] tracing/probes: add traceprobe_expand_dentry_args() helper

[Masami Hiramatsu]

Hi Ye,

On Thu, 25 Jan 2024 15:39:16 +0800
Ye Bin <yebin10@huawei.com> wrote:

> Add traceprobe_expand_dentry_args() to expand dentry args. this API is
> prepare to support "%pd" print format for kprobe.
> 
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>  kernel/trace/trace_probe.c | 50 ++++++++++++++++++++++++++++++++++++++
>  kernel/trace/trace_probe.h |  2 ++
>  2 files changed, 52 insertions(+)
> 
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index 4dc74d73fc1d..0c1caf0f474a 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -1565,6 +1565,56 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
>  	return ERR_PTR(ret);
>  }
>  
> +/* @buf: *buf must be equal to NULL. Caller must to free *buf */
> +int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
> +{
> +	int i, used, ret;
> +	int bufsize = MAX_DENTRY_ARGS_LEN;

nit: this bufsize is consistent, thus you should use the MAX_DENTRY_ARGS_LEN
     directly. (or add 'const' or maybe you can update bufsize as remaining size)

Thanks,

> +	char *tmpbuf = NULL;
> +
> +	if (*buf)
> +		return -EINVAL;
> +
> +	used = 0;
> +	for (i = 0; i < argc; i++) {
> +		if (glob_match("*:%pd", argv[i])) {
> +			char *tmp;
> +			char *equal;
> +
> +			if (!tmpbuf) {
> +				tmpbuf = kmalloc(bufsize, GFP_KERNEL);
> +				if (!tmpbuf)
> +					return -ENOMEM;
> +			}
> +
> +			tmp = kstrdup(argv[i], GFP_KERNEL);
> +			if (!tmp)
> +				goto nomem;
> +
> +			equal = strchr(tmp, '=');
> +			if (equal)
> +				*equal = '\0';
> +			tmp[strlen(argv[i]) - 4] = '\0';
> +			ret = snprintf(tmpbuf + used, bufsize - used,
> +				       "%s%s+0x0(+0x%zx(%s)):string",
> +				       equal ? tmp : "", equal ? "=" : "",
> +				       offsetof(struct dentry, d_name.name),
> +				       equal ? equal + 1 : tmp);
> +			kfree(tmp);
> +			if (ret >= bufsize - used)
> +				goto nomem;
> +			argv[i] = tmpbuf + used;
> +			used += ret + 1;
> +		}
> +	}
> +
> +	*buf = tmpbuf;
> +	return 0;
> +nomem:
> +	kfree(tmpbuf);
> +	return -ENOMEM;
> +}
> +
>  void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
>  {
>  	clear_btf_context(ctx);
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 850d9ecb6765..5800513439f3 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -34,6 +34,7 @@
>  #define MAX_ARRAY_LEN		64
>  #define MAX_ARG_NAME_LEN	32
>  #define MAX_BTF_ARGS_LEN	128
> +#define MAX_DENTRY_ARGS_LEN	256
>  #define MAX_STRING_SIZE		PATH_MAX
>  #define MAX_ARG_BUF_LEN		(MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
>  
> @@ -402,6 +403,7 @@ extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
>  const char **traceprobe_expand_meta_args(int argc, const char *argv[],
>  					 int *new_argc, char *buf, int bufsize,
>  					 struct traceprobe_parse_context *ctx);
> +extern int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf);
>  
>  extern int traceprobe_update_arg(struct probe_arg *arg);
>  extern void traceprobe_free_probe_arg(struct probe_arg *arg);
> -- 
> 2.31.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v5 4/8] tracing/probes: support '%pd/%pD' type for fprobe

[Masami Hiramatsu]

On Thu, 25 Jan 2024 15:39:19 +0800
Ye Bin <yebin10@huawei.com> wrote:

> Support print type '%pd/%pD' for print dentry's or file's name.
> 

nit: Looks good to me. but the patch ordering seems a bit strange.
This should be next to [2/8].

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you,

> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>  kernel/trace/trace_fprobe.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
> index 7d2ddbcfa377..988d68e906ad 100644
> --- a/kernel/trace/trace_fprobe.c
> +++ b/kernel/trace/trace_fprobe.c
> @@ -976,6 +976,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
>  	char gbuf[MAX_EVENT_NAME_LEN];
>  	char sbuf[KSYM_NAME_LEN];
>  	char abuf[MAX_BTF_ARGS_LEN];
> +	char *dbuf = NULL;
>  	bool is_tracepoint = false;
>  	struct tracepoint *tpoint = NULL;
>  	struct traceprobe_parse_context ctx = {
> @@ -1086,6 +1087,10 @@ static int __trace_fprobe_create(int argc, const char *argv[])
>  		argv = new_argv;
>  	}
>  
> +	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
> +	if (ret)
> +		goto out;
> +
>  	/* setup a probe */
>  	tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
>  				argc, is_return);
> @@ -1131,6 +1136,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
>  	trace_probe_log_clear();
>  	kfree(new_argv);
>  	kfree(symbol);
> +	kfree(dbuf);
>  	return ret;
>  
>  parse_error:
> -- 
> 2.31.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v5 5/8] tracing: add new type "%pd/%pD" in readme_msg[]

[Masami Hiramatsu]

On Thu, 25 Jan 2024 15:39:20 +0800
Ye Bin <yebin10@huawei.com> wrote:

> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>  kernel/trace/trace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 2a7c6fd934e9..13197d3b86bd 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -5745,7 +5745,7 @@ 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, char, string, symbol,\n"
>  	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
> -	"\t           symstr, <type>\\[<array-size>\\]\n"
> +	"\t           symstr, %pd/%pD <type>\\[<array-size>\\]\n"

Almost! you missed the ',' after %pd/%pD. :)

Thank you,


>  #ifdef CONFIG_HIST_TRIGGERS
>  	"\t    field: <stype> <name>;\n"
>  	"\t    stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
> -- 
> 2.31.1
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v5 7/8] selftests/ftrace: add kprobe test cases for VFS type "%pd" and "%pD"

[Masami Hiramatsu]

On Thu, 25 Jan 2024 15:39:22 +0800
Ye Bin <yebin10@huawei.com> wrote:

> This patch adds test cases for new print format type "%pd/%pD".The test cases
> test the following items:
> 1. Test README if add "%pd/%pD" type;
> 2. Test "%pd" type for dput();
> 3. Test "%pD" type for vfs_read();
> 
> This test case require enable CONFIG_HAVE_FUNCTION_ARG_ACCESS_API configuration.
> 
> Signed-off-by: Ye Bin <yebin10@huawei.com>
> ---
>  .../ftrace/test.d/kprobe/kprobe_args_vfs.tc   | 43 +++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
> new file mode 100644
> index 000000000000..cf0599b90f1a
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
> @@ -0,0 +1,43 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Kprobe event VFS type argument
> +# requires: kprobe_events
> +
> +: "Test argument %pd/%pD in README"
> +grep -q "%pd/%pD" README

No. This means, if the kernel doesn't support %pd/%pD, this test fails.
But the latest version of the ftracetest will be used for testing stable
kernels (which will not support this feature).
So you should make test returning 'unsupported' for that case.

You can add a requirement as

# requires: kprobe_events "%pd/%pD":README

(e.g. tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc)

Thank you,

> +
> +: "Test argument %pd with name"
> +echo 'p:testprobe dput name=$arg1:%pd' > kprobe_events
> +echo 1 > events/kprobes/testprobe/enable
> +grep -q "1" events/kprobes/testprobe/enable
> +echo 0 > events/kprobes/testprobe/enable
> +grep "dput" trace | grep -q "enable"
> +echo "" > kprobe_events
> +echo "" > trace
> +
> +: "Test argument %pd without name"
> +echo 'p:testprobe dput $arg1:%pd' > kprobe_events
> +echo 1 > events/kprobes/testprobe/enable
> +grep -q "1" events/kprobes/testprobe/enable
> +echo 0 > events/kprobes/testprobe/enable
> +grep "dput" trace | grep -q "enable"
> +echo "" > kprobe_events
> +echo "" > trace
> +
> +: "Test argument %pD with name"
> +echo 'p:testprobe vfs_read name=$arg1:%pD' > kprobe_events
> +echo 1 > events/kprobes/testprobe/enable
> +grep -q "1" events/kprobes/testprobe/enable
> +echo 0 > events/kprobes/testprobe/enable
> +grep "vfs_read" trace | grep -q "enable"
> +echo "" > kprobe_events
> +echo "" > trace
> +
> +: "Test argument %pD without name"
> +echo 'p:testprobe vfs_read $arg1:%pD' > kprobe_events
> +echo 1 > events/kprobes/testprobe/enable
> +grep -q "1"  events/kprobes/testprobe/enable
> +echo 0 > events/kprobes/testprobe/enable
> +grep "vfs_read" trace | grep -q "enable"
> +echo "" > kprobe_events
> +echo "" > trace
> -- 
> 2.31.1
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>