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

On Thu, Aug 13, 2020 at 9:08 AM lijiang <lijiang(a)redhat.com&gt; 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(a)redhat.com&gt; wrote: >>> >>> 在 2020年08月07日 00:00, crash-utility-request(a)redhat.com 写道: >>>> Message: 5 >>>> Date: Thu, 6 Aug 2020 09:30:22 -0400 >>>> From: Dave Wysochanski <dwysocha(a)redhat.com&gt; >>>> To: crash-utility(a)redhat.com >>>> Subject: [Crash-utility] [PATCH v3] Fix "log" command when crash is >>>> started with "--minimal" option >>>> Message-ID: <20200806133022.2127538-1-dwysocha(a)redhat.com&gt; >>>> >>>> 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(a)redhat.com&gt; >>>> Reviewed-by: Wang Long <w(a)laoqinren.net&gt; >>>> Tested-by: Mathias Krause <minipli(a)grsecurity.net&gt; >>>> --- >>>> 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?