On 2024/1/23 22:40, Masami Hiramatsu (Google) wrote:
On Tue, 23 Jan 2024 17:21:35 +0800
Ye Bin <yebi...@huawei.com> wrote:
Similar to '%pd' for printk, use '%pd' for print struct dentry's name.
Signed-off-by: Ye Bin <yebi...@huawei.com>
---
kernel/trace/trace_kprobe.c | 6 ++++++
kernel/trace/trace_probe.h | 1 +
2 files changed, 7 insertions(+)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index c4c6e0e0068b..00b74530fbad 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[MAX_DENTRY_ARGS_LEN];
Hmm, no, I don't like to expand stack anymore. Please allocate it
from heap.
Do I need to change the other buffers on the stacks to allocate memory
from heap?
struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
switch (argv[0][0]) {
@@ -930,6 +931,11 @@ static int __trace_kprobe_create(int argc, const char
*argv[])
argv = new_argv;
}
+ ret = traceprobe_expand_dentry_args(argc, argv, dbuf,
+ MAX_DENTRY_ARGS_LEN);
+ if (ret)
+ goto out;
And calling this here will not cover the trace_fprobe.
Could you call this from traceprobe_expand_meta_args() instead of
calling it directly from trace_kprobe? Then it can be used from
fprobe_event too.
Thank you,
At first I wanted to implement the extension logic in
traceprobe_expand_meta_args(),
but I found that the code was difficult to understand when I started
writing. If fprobe_event
wants to support this function, is traceprobe_expand_dentry_args() also
called? Or re-encapsulate
an interface to include the logic of different extensions. In this way,
the same buffer is used for
the entire extension process, and the extension function needs to return
the information about
the length of the buffer.
+
/* setup a probe */
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
argc, is_return);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 553371a4e0b1..d9c053824975 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
Why do you think
I determined this value according to the extreme case that a parameter
is expanded to occupy
64 bytes, and a maximum of four such large parameters are supported.
#define MAX_STRING_SIZE PATH_MAX
#define MAX_ARG_BUF_LEN (MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
--
2.31.1
