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 v7 vs v6:
1. Squash [1/8] to [3/8] patches into 1 patch;
2. Split readme_msg[] into each patch;
Diff v6 vs v5:
1. Add const for 'bufsize' in PATCH [1];
2. Move PATCH 'tracing/probes: support '%pd/%pD' type for fprobe' after
PATCH "tracing/probes: support '%pd' type for print struct dentry's name".
3. Add requires '"%pd/%pD":README' for testcase.
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 (5):
tracing/probes: support '%pd' type for print struct dentry's name
tracing/probes: support '%pD' type for print struct file's name
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 | 40 ++++++++++++
8 files changed, 164 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
Hi Ye,
On Wed, 20 Mar 2024 21:29:19 +0800
Ye Bin <[email protected]> wrote:
> 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.
Thanks for update! This series looks good to me.
Acked-by: Masami Hiramatsu (Google) <[email protected]>
Let me pick this and test.
Thank you!
>
> Diff v7 vs v6:
> 1. Squash [1/8] to [3/8] patches into 1 patch;
> 2. Split readme_msg[] into each patch;
>
> Diff v6 vs v5:
> 1. Add const for 'bufsize' in PATCH [1];
> 2. Move PATCH 'tracing/probes: support '%pd/%pD' type for fprobe' after
> PATCH "tracing/probes: support '%pd' type for print struct dentry's name".
> 3. Add requires '"%pd/%pD":README' for testcase.
>
> 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 (5):
> tracing/probes: support '%pd' type for print struct dentry's name
> tracing/probes: support '%pD' type for print struct file's name
> 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 | 40 ++++++++++++
> 8 files changed, 164 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
>
>
--
Masami Hiramatsu (Google) <[email protected]>
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 <[email protected]>
---
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