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

-----Original Message----- > From: crash-utility-bounces(a)redhat.com <crash-utility-bounces(a)redhat.com&gt; On Behalf Of lijiang > Sent: Friday, August 14, 2020 8:31 AM > To: David Wysochanski <dwysocha(a)redhat.com&gt; > Cc: Discussion list for crash utility usage, maintenance and development <crash-utility(a)redhat.com&gt; > Subject: Re: [Crash-utility] Crash-utility Digest, Vol 179, Issue 4 > > 在 2020年08月13日 22:58, David Wysochanski 写道: > > 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. > > > Thanks for your confirmation. > > > 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? > > > No, please do not add my signed-off-by and review-by line. > > If you and Kazu have no objection, you could post it again with the above changes. No objection. I can ack a new one with the above change.

Thanks, Kazu > Otherwise Kazu can help to merge your last patch, because it can also work. > > Thanks. > Lianbo > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility