On Tue, 23 Jan 2024 17:21:35 +0800Do I need to change the other buffers on the stacks to allocate memory from heap?
Ye Bin <yebin10@xxxxxxxxxx> wrote:
Similar to '%pd' for printk, use '%pd' for print struct dentry's name.Hmm, no, I don't like to expand stack anymore. Please allocate it
Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
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];
from heap.
At first I wanted to implement the extension logic in traceprobe_expand_meta_args(),struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };And calling this here will not cover the trace_fprobe.
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;
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,
I determined this value according to the extreme case that a parameter is expanded to occupy+Why do you think
/* 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
#define MAX_STRING_SIZE PATH_MAX
#define MAX_ARG_BUF_LEN (MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
--
2.31.1