From: Steven Rostedt <rostedt@kernel.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Namhyung Kim <namhyung@kernel.org>,
Takaya Saeki <takayas@google.com>,
Tom Zanussi <zanussi@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ian Rogers <irogers@google.com>,
Douglas Raillard <douglas.raillard@arm.com>
Subject: [PATCH v2 8/8] tracing: Show printable characters in syscall arrays
Date: Tue, 23 Sep 2025 09:05:05 -0400 [thread overview]
Message-ID: <20250923130714.766397031@kernel.org> (raw)
In-Reply-To: 20250923130457.901085554@kernel.org
From: Steven Rostedt <rostedt@goodmis.org>
When displaying the contents of the user space data passed to the kernel,
instead of just showing the array values, also print any printable
content.
Instead of just:
bash-1113 [003] ..... 3433.290654: sys_write(fd: 2, buf: 0x555a8deeddb0 (72:6f:6f:74:40:64:65:62:69:61:6e:2d:78:38:36:2d:36:34:3a:7e:23:20), count: 0x16)
Display:
bash-1113 [003] ..... 3433.290654: sys_write(fd: 2, buf: 0x555a8deeddb0 (72:6f:6f:74:40:64:65:62:69:61:6e:2d:78:38:36:2d:36:34:3a:7e:23:20) "root@debian-x86-64:~# ", count: 0x16)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace_syscalls.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 367e10096c6f..0625a32f01dd 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -155,6 +155,8 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
trace_seq_printf(s, "%s(", entry->name);
for (i = 0; i < entry->nb_args; i++) {
+ bool printable = false;
+ char *str;
if (trace_seq_has_overflowed(s))
goto end;
@@ -193,8 +195,11 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
val = trace->args[entry->user_arg_size];
+ str = ptr;
trace_seq_puts(s, " (");
for (int x = 0; x < len; x++, ptr++) {
+ if (isascii(*ptr) && isprint(*ptr))
+ printable = true;
if (x)
trace_seq_putc(s, ':');
trace_seq_printf(s, "%02x", *ptr);
@@ -203,6 +208,22 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
trace_seq_printf(s, ", %s", EXTRA);
trace_seq_putc(s, ')');
+
+ /* If nothing is printable, don't bother printing anything */
+ if (!printable)
+ continue;
+
+ trace_seq_puts(s, " \"");
+ for (int x = 0; x < len; x++) {
+ if (isascii(str[x]) && isprint(str[x]))
+ trace_seq_putc(s, str[x]);
+ else
+ trace_seq_putc(s, '.');
+ }
+ if (len < val)
+ trace_seq_printf(s, "\"%s", EXTRA);
+ else
+ trace_seq_putc(s, '"');
}
trace_seq_putc(s, ')');
--
2.50.1
prev parent reply other threads:[~2025-09-23 13:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-23 13:04 [PATCH v2 0/8] tracing: Show contents of syscall trace event user space fields Steven Rostedt
2025-09-23 13:04 ` [PATCH v2 1/8] tracing: Replace syscall RCU pointer assignment with READ/WRITE_ONCE() Steven Rostedt
2025-09-23 13:04 ` [PATCH v2 2/8] tracing: Have syscall trace events show "0x" for values greater than 10 Steven Rostedt
2025-09-23 13:05 ` [PATCH v2 3/8] tracing: Have syscall trace events read user space string Steven Rostedt
2025-09-25 7:26 ` Peter Zijlstra
2025-09-25 11:15 ` Steven Rostedt
2025-09-27 14:43 ` Steven Rostedt
2025-09-23 13:05 ` [PATCH v2 4/8] tracing: Have system call events record user array data Steven Rostedt
2025-09-23 13:05 ` [PATCH v2 5/8] tracing: Display some syscall arrays as strings Steven Rostedt
2025-09-23 13:05 ` [PATCH v2 6/8] tracing: Allow syscall trace events to read more than one user parameter Steven Rostedt
2025-09-23 13:05 ` [PATCH v2 7/8] tracing: Add syscall_user_buf_size to limit amount written Steven Rostedt
2025-09-24 9:49 ` kernel test robot
2025-09-23 13:05 ` Steven Rostedt [this message]
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