From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7492257848; Tue, 21 Oct 2025 00:52:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761007933; cv=none; b=MPDI9nCe00kKvvtmdgXOEwH3ZFmP83dxtnOUJiRapSIbs8nTZFVlx//MkUAH+rTS13AUQD/tmFWojLaSA/WnPswh6f1814wPliJ+qX7Mpq5aCGGPpxGpd9UlU1xthP41HAaC6HZLRL4eqUGhlNMhT4FPmDiTbEE9muLeNexb18A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761007933; c=relaxed/simple; bh=UQDz1VR9VWyasMtuZd7MP4v+qxsLEjU3f+GwlGCWrEA=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=PgfVU3OYue0PgcX38B2fchCDeImFE6VhDvJbhu54jz7w7KPjfoPcGz07qpUWOGkV/H6Y9qnm37SOFINVJ8xzvvNCxWHToG+9NxHpqgnn/xZtr5UR9S78cY04efjLSCswNdF9JHowUok3TG7pOzdlMqaQPh90lskcWoy0S9G4wj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e1BYNdW2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="e1BYNdW2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5A93C2BCB2; Tue, 21 Oct 2025 00:52:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761007933; bh=UQDz1VR9VWyasMtuZd7MP4v+qxsLEjU3f+GwlGCWrEA=; h=Date:From:To:Cc:Subject:References:From; b=e1BYNdW2eTIA8pAi7ppSc3M+++VcaSBgPZgNB8MlKpLQJBBh4bNB9fpWvKDjRSoe8 /yNv2xj8MXe393oPf/AFV1kU/TZXyedT0Tq2xHUt6Ox4ov8m4XPPiBqrIWebyP2fJ2 2A41U662vfx1Y24xGlTU0oqLCgIcszgtkj+iEeFD/iD/RtkH1RN7uyZCH6Uh8c7TR8 c73lv7IZlCQwaooeTb7Iva8nEWst+8lZR7AdxPmk/mXlMOddJH/zekWW0A9xKh330l 8k/sQlX15uNKDiT8q4a5/WuXVFXngEIdt7W7+vTK0VfGtrhhO7G1LPz1jqmC/QolV9 BHSgtkRvcfvtQ== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1vB0c6-000000020BK-2LUX; Mon, 20 Oct 2025 20:52:34 -0400 Message-ID: <20251021005234.413066934@kernel.org> User-Agent: quilt/0.68 Date: Mon, 20 Oct 2025 20:52:08 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Peter Zijlstra , Namhyung Kim , Takaya Saeki , Tom Zanussi , Thomas Gleixner , Ian Rogers , Douglas Raillard , Arnaldo Carvalho de Melo , Jiri Olsa , Adrian Hunter , Ingo Molnar Subject: [PATCH v4 13/13] tracing: Have persistent ring buffer print syscalls normally References: <20251021005155.705735078@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Steven Rostedt 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) --- Changes since v3: https://lore.kernel.org/20251015173550.225723717@kernel.org - Fixed up the code to determine if it's a syscall event or not when CONFIG_FTRACE_SYSCALLS is not defined (kernel test robot) kernel/trace/trace.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2aee9a3088f4..a765792d3428 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -4219,6 +4220,22 @@ static void test_cpu_buff_start(struct trace_iterator *iter) iter->cpu); } +#ifdef CONFIG_FTRACE_SYSCALLS +static bool is_syscall_event(struct trace_event *event) +{ + return (event->funcs == &enter_syscall_print_funcs) || + (event->funcs == &exit_syscall_print_funcs); + +} +#define syscall_buf_size CONFIG_TRACE_SYSCALL_BUF_SIZE_DEFAULT +#else +static inline bool is_syscall_event(struct trace_event *event) +{ + return false; +} +#define syscall_buf_size 0 +#endif /* CONFIG_FTRACE_SYSCALLS */ + static enum print_line_t print_trace_fmt(struct trace_iterator *iter) { struct trace_array *tr = iter->tr; @@ -4251,10 +4268,12 @@ 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) && + !is_syscall_event(event)) return print_event_fields(iter, event); - + } return event->funcs->trace(iter, sym_flags, event); } @@ -11436,7 +11455,7 @@ __init static int tracer_alloc_buffers(void) global_trace.flags = TRACE_ARRAY_FL_GLOBAL; - global_trace.syscall_buf_sz = CONFIG_TRACE_SYSCALL_BUF_SIZE_DEFAULT; + global_trace.syscall_buf_sz = syscall_buf_size; INIT_LIST_HEAD(&global_trace.systems); INIT_LIST_HEAD(&global_trace.events); -- 2.51.0