[Crash-utility] Crash-utility Digest, Vol 179, Issue 4

[lijiang]

在 2020年08月07日 00:00, crash-utility-request at redhat.com 写道:
> Message: 5
> Date: Thu,  6 Aug 2020 09:30:22 -0400
> From: Dave Wysochanski <dwysocha at redhat.com>
> To: crash-utility at redhat.com
> Subject: [Crash-utility] [PATCH v3] Fix "log" command when crash is
> 	started	with "--minimal" option
> Message-ID: <20200806133022.2127538-1-dwysocha at redhat.com>
> 
> Commit c86250bce29f introduced the useful '-T' option to print the
> log timestamp in human-readable form.  However, this option does
> not work when crash is invoked with '--minimal' mode, and if tried,
> crash will spin at 100% and continuously crash at a divide by 0
> because machdep->hz == 0.
> 
> Fix this by disallowing this option in minimal mode.  In addition,
> only calculate the logic to calculate kt->boot_date.tv_sec
> when this option is enabled.
> 
Hi, Dave Wysochanski

Thank you for the patch.

> Fixes: c86250bce29f ("Introduction of the "log -T" option...")
> Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
> Reviewed-by: Wang Long <w at laoqinren.net>
> Tested-by: Mathias Krause <minipli at grsecurity.net>
> ---
>  kernel.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel.c b/kernel.c
> index 5ed6021..95119f3 100644
> --- a/kernel.c
> +++ b/kernel.c
> @@ -4939,7 +4939,10 @@ cmd_log(void)
>          if (argerrs)
>                  cmd_usage(pc->curcmd, SYNOPSIS);
>  
> -	if (kt->boot_date.tv_sec == 0) {
> +	if (msg_flags & SHOW_LOG_CTIME && pc->flags & MINIMAL_MODE)
> +		error(FATAL, "log: option 'T' not available in minimal mode\n");
> +
> +	if (msg_flags & SHOW_LOG_CTIME && kt->boot_date.tv_sec == 0) {

The above two 'if' statements have the same checking condition, would you mind putting them together
as a statement block? E.g:

+       if (msg_flags & SHOW_LOG_CTIME) {
+               if (pc->flags & MINIMAL_MODE) {
+                       error(WARNING, "the option '-T' not available in minimal mode\n");
+                       return;
+               }
+
+               if (kt->boot_date.tv_sec == 0) {
...
+               }
        }

In addition, might it be more reasonable to issue a warning instead of a fatal error?

Thanks.
Lianbo

>  		ulonglong uptime_jiffies;
>  		ulong  uptime_sec;
>  		get_uptime(NULL, &uptime_jiffies);
> -- 2.27.0