Re: [PATCHv3 25/50] parisc: Add show_stack_loglvl()
From: Helge Deller
Date: Sat Apr 18 2020 - 16:55:29 EST
On 18.04.20 22:19, Dmitry Safonov wrote:
> 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).
>
> 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: Helge Deller <deller@xxxxxx>
> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> Cc: linux-parisc@xxxxxxxxxxxxxxx
> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@xxxxxxxxxx/T/#u
> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
> ---
> arch/parisc/kernel/traps.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)
Acked-by: Helge Deller <deller@xxxxxx>
Thanks!
Helge
>
> diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
> index 82fc01189488..c2411de3730f 100644
> --- a/arch/parisc/kernel/traps.c
> +++ b/arch/parisc/kernel/traps.c
> @@ -49,7 +49,7 @@
> #include "../math-emu/math-emu.h" /* for handle_fpe() */
>
> static void parisc_show_stack(struct task_struct *task,
> - struct pt_regs *regs);
> + struct pt_regs *regs, const char *loglvl);
>
> static int printbinary(char *buf, unsigned long x, int nbits)
> {
> @@ -155,7 +155,7 @@ void show_regs(struct pt_regs *regs)
> printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
> printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
>
> - parisc_show_stack(current, regs);
> + parisc_show_stack(current, regs, KERN_DEFAULT);
> }
> }
>
> @@ -170,37 +170,43 @@ static DEFINE_RATELIMIT_STATE(_hppa_rs,
> }
>
>
> -static void do_show_stack(struct unwind_frame_info *info)
> +static void do_show_stack(struct unwind_frame_info *info, const char *loglvl)
> {
> int i = 1;
>
> - printk(KERN_CRIT "Backtrace:\n");
> + printk("%sBacktrace:\n", loglvl);
> while (i <= MAX_UNWIND_ENTRIES) {
> if (unwind_once(info) < 0 || info->ip == 0)
> break;
>
> if (__kernel_text_address(info->ip)) {
> - printk(KERN_CRIT " [<" RFMT ">] %pS\n",
> - info->ip, (void *) info->ip);
> + printk("%s [<" RFMT ">] %pS\n",
> + loglvl, info->ip, (void *) info->ip);
> i++;
> }
> }
> - printk(KERN_CRIT "\n");
> + printk("%s\n", loglvl);
> }
>
> static void parisc_show_stack(struct task_struct *task,
> - struct pt_regs *regs)
> + struct pt_regs *regs, const char *loglvl)
> {
> struct unwind_frame_info info;
>
> unwind_frame_init_task(&info, task, regs);
>
> - do_show_stack(&info);
> + do_show_stack(&info, loglvl);
> +}
> +
> +void show_stack_loglvl(struct task_struct *t, unsigned long *sp,
> + const char *loglvl)
> +{
> + parisc_show_stack(t, NULL, loglvl);
> }
>
> void show_stack(struct task_struct *t, unsigned long *sp)
> {
> - parisc_show_stack(t, NULL);
> + show_stack_loglvl(t, sp, KERN_CRIT)
> }
>
> int is_valid_bugaddr(unsigned long iaoq)
> @@ -446,7 +452,7 @@ void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long o
> /* show_stack(NULL, (unsigned long *)regs->gr[30]); */
> struct unwind_frame_info info;
> unwind_frame_init(&info, current, regs);
> - do_show_stack(&info);
> + do_show_stack(&info, KERN_CRIT);
> }
>
> printk("\n");
>