From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Shuah Khan <shuah@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: [PATCH v3 4/5] tracing/probes: Extend max length of argument string
Date: Tue, 14 Jul 2026 10:10:04 +0900 [thread overview]
Message-ID: <178399140457.27810.11387684872148824707.stgit@devnote2> (raw)
In-Reply-To: <178399136606.27810.4469135881050354189.stgit@devnote2>
From: Masami Hiramatsu <mhiramat@kernel.org>
To support BTF argument parsing (such as accessing fields within nested
structures via typecasting), the maximum argument string length needs
to be extended. Extend MAX_ARGSTR_LEN from 63 to 255.
Since MAX_ARGSTR_LEN was previously reused to format command heads in
trace_*probe_match_command_head() functions, introduce a dedicated
MAX_COMMON_HEAD_LEN (63) macro for matching command heads and switch
these functions to use the new macro.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Make the MAX_ARGSTR_LEN to 255 instead of 256.
---
kernel/trace/trace_fprobe.c | 2 +-
kernel/trace/trace_kprobe.c | 2 +-
kernel/trace/trace_probe.h | 3 ++-
kernel/trace/trace_uprobe.c | 2 +-
.../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 2 +-
.../ftrace/test.d/dynevent/tprobe_syntax_errors.tc | 2 +-
.../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 2 +-
7 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 536781cd4c47..5638a90e61cc 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -238,7 +238,7 @@ static bool trace_fprobe_is_busy(struct dyn_event *ev)
static bool trace_fprobe_match_command_head(struct trace_fprobe *tf,
int argc, const char **argv)
{
- char buf[MAX_ARGSTR_LEN + 1];
+ char buf[MAX_COMMON_HEAD_LEN + 1];
if (!argc)
return true;
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index cfa807d8e760..cc24e992732c 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -149,7 +149,7 @@ static bool trace_kprobe_is_busy(struct dyn_event *ev)
static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
int argc, const char **argv)
{
- char buf[MAX_ARGSTR_LEN + 1];
+ char buf[MAX_COMMON_HEAD_LEN + 1];
if (!argc)
return true;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index e64e323244a5..e6d427910c4f 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -32,7 +32,8 @@
#include "trace_output.h"
#define MAX_TRACE_ARGS 128
-#define MAX_ARGSTR_LEN 63
+#define MAX_ARGSTR_LEN 255
+#define MAX_COMMON_HEAD_LEN 63
#define MAX_ARRAY_LEN 64
#define MAX_ARG_NAME_LEN 32
#define MAX_BTF_ARGS_LEN 128
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index b2e264a4b96c..67bd8fd91e3e 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -281,7 +281,7 @@ static bool trace_uprobe_is_busy(struct dyn_event *ev)
static bool trace_uprobe_match_command_head(struct trace_uprobe *tu,
int argc, const char **argv)
{
- char buf[MAX_ARGSTR_LEN + 1];
+ char buf[MAX_COMMON_HEAD_LEN + 1];
int len;
if (!argc)
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
index e9d7e6919c7f..984ab94df213 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
@@ -75,7 +75,7 @@ check_error 'f vfs_read ^arg123456789012345678901234567890=@11' # ARG_NAME_TOO_L
check_error 'f vfs_read ^=@11' # NO_ARG_NAME
check_error 'f vfs_read ^var.1=@11' # BAD_ARG_NAME
check_error 'f vfs_read var1=@11 ^var1=@12' # USED_ARG_NAME
-check_error 'f vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))' # ARG_TOO_LONG
+check_error 'f vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))))))))))))))))))))))' # ARG_TOO_LONG
check_error 'f vfs_read arg1=^' # NO_ARG_BODY
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc
index ffe8ffef4027..2d0905b2c8b7 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc
@@ -61,7 +61,7 @@ check_error 't kfree ^arg123456789012345678901234567890=@11' # ARG_NAME_TOO_LOG
check_error 't kfree ^=@11' # NO_ARG_NAME
check_error 't kfree ^var.1=@11' # BAD_ARG_NAME
check_error 't kfree var1=@11 ^var1=@12' # USED_ARG_NAME
-check_error 't kfree ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))' # ARG_TOO_LONG
+check_error 't kfree ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))))))))))))))))))))))' # ARG_TOO_LONG
check_error 't kfree arg1=^' # NO_ARG_BODY
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
index 21ce8414459f..d28f63b7e8a9 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
@@ -71,7 +71,7 @@ check_error 'p vfs_read ^arg123456789012345678901234567890=@11' # ARG_NAME_TOO_L
check_error 'p vfs_read ^=@11' # NO_ARG_NAME
check_error 'p vfs_read ^var.1=@11' # BAD_ARG_NAME
check_error 'p vfs_read var1=@11 ^var1=@12' # USED_ARG_NAME
-check_error 'p vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))' # ARG_TOO_LONG
+check_error 'p vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))))))))))))))))))))))' # ARG_TOO_LONG
check_error 'p vfs_read arg1=^' # NO_ARG_BODY
# instruction boundary check is valid on x86 (at this moment)
next prev parent reply other threads:[~2026-07-14 1:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-14 1:09 [PATCH v3 0/5] tracing/probes: Clean up and refactor argument parser Masami Hiramatsu (Google)
2026-07-14 1:09 ` [PATCH v3 1/5] tracing/probes: Refactor parse_probe_vars() Masami Hiramatsu (Google)
2026-07-14 1:09 ` [PATCH v3 2/5] tracing/probes: Refactor parse_probe_arg() Masami Hiramatsu (Google)
2026-07-14 1:09 ` [PATCH v3 3/5] tracing/probes: Sort ERRORS list in trace_probe.h alphabetically Masami Hiramatsu (Google)
2026-07-14 1:10 ` Masami Hiramatsu (Google) [this message]
2026-07-14 1:10 ` [PATCH v3 5/5] tracing/probes: Eliminate recursion in parse_probe_arg() Masami Hiramatsu (Google)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=178399140457.27810.11387684872148824707.stgit@devnote2 \
--to=mhiramat@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=rostedt@goodmis.org \
--cc=shuah@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.