On Wed, Aug 8, 2018 at 11:53 PM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: > On 08/08/2018 11:18 AM, Hari Vyas wrote: >> On Tue, Aug 7, 2018 at 5:57 PM, Greg KH <greg@xxxxxxxxx> wrote: >>> On Tue, Aug 07, 2018 at 04:33:48PM +0530, Hari Vyas wrote: >>>> bad_mode() handler is called for invalid or undefined >>>> instruction in el1 level or when irq,fiq,sync or error >>>> situation happen in el1 or el0 level. >>>> >>>> As per latest code, above abnormal situation may not result in >>>> panic always due to die() call if user mode is determined at >>>> that moment. That will just result in kill of current process >>>> and panic will be avoided which it must not. >>>> >>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=200637 >>>> Signed-off-by: Hari Vyas <hari.vyas@xxxxxxxxxxxx> >>>> --- >>>> arch/arm64/kernel/traps.c | 1 - >>>> 1 file changed, 1 deletion(-) >>>> >>>> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c >>>> index d399d45..716ee73 100644 >>>> --- a/arch/arm64/kernel/traps.c >>>> +++ b/arch/arm64/kernel/traps.c >>>> @@ -621,7 +621,6 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) >>>> handler[reason], smp_processor_id(), esr, >>>> esr_get_class_string(esr)); >>>> >>>> - die("Oops - bad mode", regs, 0); >>>> local_daif_mask(); >>>> panic("bad mode"); >>>> } >>>> -- >>>> 1.9.1 >>> >>> <formletter> >>> >>> This is not the correct way to submit patches for inclusion in the >>> stable kernel tree. Please read: >>> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html >>> for how to do this properly. >>> >>> </formletter> >> >> Thanks. Probably my mistake to include stable kernel list for regular >> minor patch. >> In any case, will take care about it along with arm maintainers and >> developers review comments which I am awaiting. > > Also, if this is a real fix, then providing an appropriate Fixes: tag > would help understand when this broke, and how far back this needs to be > backported to. This of course, assumes that your patch is the right > course of action. > -- As far as I know, bad mode was earlier(linux 3.14 onwards) also not resulting in panic always. Trap-exception framework is recently changed some time back but this concern remains same. I am also awaiting a response from ARM maintainers before proceeding. Just to be more clear, this concern was pointed out in one of my previous-and-some-what-relative patch about console-verbose level restoration issue. > Florian
