From: Michael Ellerman <mpe@ellerman•id.au>
To: Dmitry Safonov <dima@arista•com>, linux-kernel@vger•kernel.org
Cc: Petr Mladek <pmladek@suse•com>, Dmitry Safonov <dima@arista•com>,
Tetsuo Handa <penguin-kernel@I-love•SAKURA.ne.jp>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Dmitry Safonov <0x7f454c46@gmail•com>,
Steven Rostedt <rostedt@goodmis•org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail•com>,
Paul Mackerras <paulus@samba•org>, Jiri Slaby <jslaby@suse•com>,
Andrew Morton <akpm@linux-foundation•org>,
linuxppc-dev@lists•ozlabs.org, Ingo Molnar <mingo@kernel•org>
Subject: Re: [PATCH 26/50] powerpc: Add show_stack_loglvl()
Date: Wed, 06 Nov 2019 20:52:52 +1100 [thread overview]
Message-ID: <8736f172mj.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20191106030542.868541-27-dima@arista.com>
Dmitry Safonov <dima@arista•com> writes:
> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
Yes, I've had bug reports where the stacktrace is missing, which is
annoying. Thanks for trying to fix the problem.
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
>
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
>
> Introduce show_stack_loglvl(), that eventually will substitute
> show_stack().
>
> Cc: Benjamin Herrenschmidt <benh@kernel•crashing.org>
> Cc: Michael Ellerman <mpe@ellerman•id.au>
> Cc: Paul Mackerras <paulus@samba•org>
> Cc: linuxppc-dev@lists•ozlabs.org
> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
> Signed-off-by: Dmitry Safonov <dima@arista•com>
> ---
> arch/powerpc/kernel/process.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
This looks good to me.
Acked-by: Michael Ellerman <mpe@ellerman•id.au> (powerpc)
cheers
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 639ceae7da9d..34b46680a196 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -2028,7 +2028,8 @@ unsigned long get_wchan(struct task_struct *p)
>
> static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
>
> -void show_stack(struct task_struct *tsk, unsigned long *stack)
> +void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
> + const char *loglvl)
> {
> unsigned long sp, ip, lr, newsp;
> int count = 0;
> @@ -2053,7 +2054,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
> }
>
> lr = 0;
> - printk("Call Trace:\n");
> + printk("%sCall Trace:\n", loglvl);
> do {
> if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
> break;
> @@ -2062,7 +2063,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
> newsp = stack[0];
> ip = stack[STACK_FRAME_LR_SAVE];
> if (!firstframe || ip != lr) {
> - printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
> + printk("%s["REG"] ["REG"] %pS",
> + loglvl, sp, ip, (void *)ip);
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> ret_addr = ftrace_graph_ret_addr(current,
> &ftrace_idx, ip, stack);
> @@ -2084,8 +2086,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
> struct pt_regs *regs = (struct pt_regs *)
> (sp + STACK_FRAME_OVERHEAD);
> lr = regs->link;
> - printk("--- interrupt: %lx at %pS\n LR = %pS\n",
> - regs->trap, (void *)regs->nip, (void *)lr);
> + printk("%s--- interrupt: %lx at %pS\n LR = %pS\n",
> + loglvl, regs->trap,
> + (void *)regs->nip, (void *)lr);
> firstframe = 1;
> }
>
> @@ -2095,6 +2098,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
> put_task_stack(tsk);
> }
>
> +void show_stack(struct task_struct *tsk, unsigned long *stack)
> +{
> + show_stack_loglvl(tsk, stack, KERN_DEFAULT);
> +}
> +
> #ifdef CONFIG_PPC64
> /* Called with hard IRQs off */
> void notrace __ppc64_runlatch_on(void)
> --
> 2.23.0
next prev parent reply other threads:[~2019-11-06 9:55 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 3:04 [PATCH 00/50] Add log level to show_stack() Dmitry Safonov
2019-11-06 3:05 ` [PATCH 26/50] powerpc: Add show_stack_loglvl() Dmitry Safonov
2019-11-06 9:52 ` Michael Ellerman [this message]
2019-11-06 16:01 ` Dmitry Safonov
2019-11-06 8:35 ` [PATCH 00/50] Add log level to show_stack() Petr Mladek
2019-11-06 16:12 ` Dmitry Safonov
2019-11-08 10:37 ` Sergey Senozhatsky
2019-11-08 13:04 ` Petr Mladek
2019-11-11 1:23 ` Sergey Senozhatsky
2019-11-11 9:12 ` Petr Mladek
2019-11-12 4:44 ` Sergey Senozhatsky
2019-11-12 4:57 ` Sergey Senozhatsky
2019-11-12 8:35 ` Petr Mladek
2019-11-12 10:12 ` Sergey Senozhatsky
2019-11-13 1:23 ` Sergey Senozhatsky
2019-11-13 2:25 ` Dmitry Safonov
2019-11-13 6:33 ` Sergey Senozhatsky
2019-11-13 8:47 ` Petr Mladek
2019-11-13 16:24 ` Steven Rostedt
2019-11-13 16:40 ` Dmitry Safonov
2019-11-15 0:50 ` Sergey Senozhatsky
2019-11-13 15:32 ` Steven Rostedt
2019-11-11 19:47 ` Dmitry Safonov
2019-11-12 2:17 ` Sergey Senozhatsky
2019-11-12 2:40 ` Dmitry Safonov
2019-11-12 4:25 ` Sergey Senozhatsky
2019-11-13 2:41 ` Dmitry Safonov
2019-11-13 2:51 ` Sergey Senozhatsky
2019-11-13 15:39 ` Steven Rostedt
2019-11-15 3:36 ` Sergey Senozhatsky
2019-11-06 9:20 ` Peter Zijlstra
2019-11-06 16:27 ` Dmitry Safonov
2019-11-06 20:34 ` Peter Zijlstra
2019-11-06 23:25 ` Russell King - ARM Linux admin
2019-11-13 15:44 ` Steven Rostedt
2019-11-08 16:28 ` Dmitry Safonov
2019-11-08 17:30 ` Russell King - ARM Linux admin
2019-11-08 21:08 ` Dmitry Safonov
2019-11-13 15:41 ` Steven Rostedt
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