From: Dmitry Safonov <dima@arista.com>
To: linux-kernel@vger.kernel.org
Cc: Dmitry Safonov <0x7f454c46@gmail.com>,
Dmitry Safonov <dima@arista.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jann Horn <jannh@google.com>, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org
Subject: [PATCH 0/3] x86/dumpstack: Print registers with the same log level as the backtrace
Date: Tue, 23 Jun 2020 17:29:55 +0100 [thread overview]
Message-ID: <20200623162958.331051-1-dima@arista.com> (raw)
show_trace_log_lvl() provides x86 platform-specific way to unwind
backtrace with a given log level. Unfortunately, registers dump(s) are
not printed with the same log level - instead, KERN_DEFAULT is always
used.
Arista's switches uses quite common setup with rsyslog, where only
urgent messages goes to console (console_log_level=KERN_ERR), everything
else goes into /var/log/ as the console baud-rate often is indecently
slow (9600 bps).
Backtrace dumps without registers printed have proven to be as useful as
morning standups. Furthermore, in order to introduce KERN_UNSUPPRESSED
(which I believe is still the most elegant way to fix raciness of sysrq[1])
the log level should be passed down the stack to register dumping
functions. Besides, I have a potential use-case for printing traces
with KERN_DEBUG level [2] (where registers dump shouldn't appear with
higher log level than the backtrace).
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/
[2]: https://lore.kernel.org/linux-doc/20190724170249.9644-1-dima@arista.com/
Dmitry Safonov (3):
x86/dumpstack: Add log_lvl to show_iret_regs()
x86/dumpstack: Add log_lvl to __show_regs()
x86/dumpstack: Show registers dump with trace's log level
arch/x86/include/asm/kdebug.h | 5 ++--
arch/x86/kernel/dumpstack.c | 23 +++++++++-------
arch/x86/kernel/process_32.c | 29 ++++++++++----------
arch/x86/kernel/process_64.c | 51 ++++++++++++++++++-----------------
4 files changed, 57 insertions(+), 51 deletions(-)
--
2.27.0
next reply other threads:[~2020-06-23 16:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 16:29 Dmitry Safonov [this message]
2020-06-23 16:29 ` [PATCH 1/3] x86/dumpstack: Add log_lvl to show_iret_regs() Dmitry Safonov
2020-06-23 16:29 ` [PATCH 2/3] x86/dumpstack: Add log_lvl to __show_regs() Dmitry Safonov
2020-06-23 16:45 ` Jann Horn
2020-06-25 16:42 ` Dmitry Safonov
2020-06-23 16:29 ` [PATCH 3/3] x86/dumpstack: Show registers dump with trace's log level Dmitry Safonov
2020-06-24 6:50 ` [PATCH 0/3] x86/dumpstack: Print registers with the same log level as the backtrace Petr Mladek
2020-06-25 16:41 ` Dmitry Safonov
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