On Thu, Aug 13, 2020 at 9:08 AM lijiang <lijiang@xxxxxxxxxx> wrote:
>
> 在 2020年08月13日 16:33, David Wysochanski 写道:
> > Hi Lianbo
> >
> > On Sat, Aug 8, 2020 at 10:46 PM lijiang <lijiang@xxxxxxxxxx> wrote:
> >>
> >> 在 2020年08月07日 00:00, crash-utility-request@xxxxxxxxxx 写道:
> >>> Message: 5
> >>> Date: Thu, 6 Aug 2020 09:30:22 -0400
> >>> From: Dave Wysochanski <dwysocha@xxxxxxxxxx>
> >>> To: crash-utility@xxxxxxxxxx
> >>> Subject: [PATCH v3] Fix "log" command when crash is
> >>> started with "--minimal" option
> >>> Message-ID: <20200806133022.2127538-1-dwysocha@xxxxxxxxxx>
> >>>
> >>> 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@xxxxxxxxxx>
> >>> Reviewed-by: Wang Long <w@xxxxxxxxxxxxx>
> >>> Tested-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
> >>> ---
> >>> 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:
> >>
> > Sure I can resubmit a fixup of v4 patch once there are no more changes needed.
> >
> >> + 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?
> >>
> >
> > If you use WARNING it will not fix the infinite loop / CPU spin at
> > 100%. You have to CTRL-C the crash program to get the prompt back.
> > So I do not think this is a good idea.
> >
> How did you reproduce it? Can you help to confirm if you have applied the correct patch
> as below?
>
> [root@intel-sharkbay-mb-03 crash]# git diff kernel.c
> diff --git a/kernel.c b/kernel.c
> index 5ed6021..6375b24 100644
> --- a/kernel.c
> +++ b/kernel.c
> @@ -4939,13 +4939,20 @@ cmd_log(void)
> if (argerrs)
> cmd_usage(pc->curcmd, SYNOPSIS);
>
> - if (kt->boot_date.tv_sec == 0) {
> - ulonglong uptime_jiffies;
> - ulong uptime_sec;
> - get_uptime(NULL, &uptime_jiffies);
> - uptime_sec = (uptime_jiffies)/(ulonglong)machdep->hz;
> - kt->boot_date.tv_sec = kt->date.tv_sec - uptime_sec;
> - kt->boot_date.tv_nsec = 0;
> + 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) {
> + ulonglong uptime_jiffies;
> + ulong uptime_sec;
> + get_uptime(NULL, &uptime_jiffies);
> + uptime_sec = (uptime_jiffies)/(ulonglong)machdep->hz;
> + kt->boot_date.tv_sec = kt->date.tv_sec - uptime_sec;
> + kt->boot_date.tv_nsec = 0;
> + }
> }
>
> if (msg_flags & SHOW_LOG_AUDIT) {
>
>
> I didn't see any problems, it's strange, this is my test steps.
>
You are right - I missed the 'return;' in your patch. The WARNING is fine.
How do you want to handle this? Do you want to take the original header
and add your signed-off-by line and commit your patch? Or do you want
me to resubmit with review-by or signed-off-by lines?
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