From: Steven Rostedt <rostedt@kernel.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-perf-users@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>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Ingo Molnar <mingo@redhat.com>
Subject: [PATCH v3 13/13] tracing: Have persistent ring buffer print syscalls normally
Date: Wed, 15 Oct 2025 13:32:27 -0400 [thread overview]
Message-ID: <20251015173550.225723717@kernel.org> (raw)
In-Reply-To: 20251015173214.760495866@kernel.org
From: Steven Rostedt <rostedt@goodmis.org>
The persistent ring buffer from a previous boot has to be careful printing
events as the print formats of random events can have pointers to strings
and such that are not available.
Ftrace static events (like the function tracer event) are stable and are
printed normally.
System call event formats are also stable. Allow them to be printed
normally as well:
Instead of:
<...>-1 [005] ...1. 57.240405: sys_enter_waitid: __syscall_nr=0xf7 (247) which=0x1 (1) upid=0x499 (1177) infop=0x7ffd5294d690 (140725988939408) options=0x5 (5) ru=0x0 (0)
<...>-1 [005] ...1. 57.240433: sys_exit_waitid: __syscall_nr=0xf7 (247) ret=0x0 (0)
<...>-1 [005] ...1. 57.240437: sys_enter_rt_sigprocmask: __syscall_nr=0xe (14) how=0x2 (2) nset=0x7ffd5294d7c0 (140725988939712) oset=0x0 (0) sigsetsize=0x8 (8)
<...>-1 [005] ...1. 57.240438: sys_exit_rt_sigprocmask: __syscall_nr=0xe (14) ret=0x0 (0)
<...>-1 [005] ...1. 57.240442: sys_enter_close: __syscall_nr=0x3 (3) fd=0x4 (4)
<...>-1 [005] ...1. 57.240463: sys_exit_close: __syscall_nr=0x3 (3) ret=0x0 (0)
<...>-1 [005] ...1. 57.240485: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param
<...>-1 [005] ...1. 57.240555: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154)
<...>-1 [005] ...1. 57.240571: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param
<...>-1 [005] ...1. 57.240620: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154)
<...>-1 [005] ...1. 57.240629: sys_enter_writev: __syscall_nr=0x14 (20) fd=0x3 (3) vec=0x7ffd5294ce50 (140725988937296) vlen=0x7 (7)
<...>-1 [005] ...1. 57.242281: sys_exit_writev: __syscall_nr=0x14 (20) ret=0x24 (36)
<...>-1 [005] ...1. 57.242286: sys_enter_reboot: __syscall_nr=0xa9 (169) magic1=0xfee1dead (4276215469) magic2=0x28121969 (672274793) cmd=0x1234567 (19088743) arg=0x0 (0)
Have:
<...>-1 [000] ...1. 91.446011: sys_waitid(which: 1, upid: 0x4d2, infop: 0x7ffdccdadfd0, options: 5, ru: 0)
<...>-1 [000] ...1. 91.446042: sys_waitid -> 0x0
<...>-1 [000] ...1. 91.446045: sys_rt_sigprocmask(how: 2, nset: 0x7ffdccdae100, oset: 0, sigsetsize: 8)
<...>-1 [000] ...1. 91.446047: sys_rt_sigprocmask -> 0x0
<...>-1 [000] ...1. 91.446051: sys_close(fd: 4)
<...>-1 [000] ...1. 91.446073: sys_close -> 0x0
<...>-1 [000] ...1. 91.446095: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC)
<...>-1 [000] ...1. 91.446165: sys_openat -> 0xfffffffffffffffe
<...>-1 [000] ...1. 91.446182: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC)
<...>-1 [000] ...1. 91.446233: sys_openat -> 0xfffffffffffffffe
<...>-1 [000] ...1. 91.446242: sys_writev(fd: 3, vec: 0x7ffdccdad790, vlen: 7)
<...>-1 [000] ...1. 91.447877: sys_writev -> 0x24
<...>-1 [000] ...1. 91.447883: sys_reboot(magic1: 0xfee1dead, magic2: 0x28121969, cmd: 0x1234567, arg: 0)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2aee9a3088f4..98d8a33d03ff 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -20,6 +20,7 @@
#include <linux/security.h>
#include <linux/seq_file.h>
#include <linux/irqflags.h>
+#include <linux/syscalls.h>
#include <linux/debugfs.h>
#include <linux/tracefs.h>
#include <linux/pagemap.h>
@@ -4251,10 +4252,13 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
* safe to use if the array has delta offsets
* Force printing via the fields.
*/
- if ((tr->text_delta) &&
- event->type > __TRACE_LAST_TYPE)
+ if ((tr->text_delta)) {
+ /* ftrace and system call events are still OK */
+ if ((event->type > __TRACE_LAST_TYPE) &&
+ (event->funcs != &enter_syscall_print_funcs) &&
+ (event->funcs != &exit_syscall_print_funcs))
return print_event_fields(iter, event);
-
+ }
return event->funcs->trace(iter, sym_flags, event);
}
--
2.51.0
next prev parent reply other threads:[~2025-10-15 17:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-15 17:32 [PATCH v3 00/13] tracing: Show contents of syscall trace event user space fields Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 01/13] tracing: Make trace_user_fault_read() exposed to rest of tracing Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 02/13] tracing: Have syscall trace events read user space string Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 03/13] perf: tracing: Simplify perf_sysenter_enable/disable() with guards Steven Rostedt
2025-10-16 11:05 ` kernel test robot
2025-10-15 17:32 ` [PATCH v3 04/13] perf: tracing: Have perf system calls read user space Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 05/13] tracing: Have system call events record user array data Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 06/13] tracing: Display some syscall arrays as strings Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 07/13] tracing: Allow syscall trace events to read more than one user parameter Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 08/13] tracing: Add a config and syscall_user_buf_size file to limit amount written Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 09/13] tracing: Show printable characters in syscall arrays Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 10/13] tracing: Add trace_seq_pop() and seq_buf_pop() Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 11/13] tracing: Add parsing of flags to the sys_enter_openat trace event Steven Rostedt
2025-10-15 17:32 ` [PATCH v3 12/13] tracing: Check for printable characters when printing field dyn strings Steven Rostedt
2025-10-20 12:19 ` Douglas Raillard
2025-10-20 18:47 ` Steven Rostedt
2025-10-15 17:32 ` Steven Rostedt [this message]
2025-10-16 10:33 ` [PATCH v3 13/13] tracing: Have persistent ring buffer print syscalls normally kernel test robot
2025-10-16 11:36 ` kernel test robot
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