Re: [PATCH 2/2] s390: mm: Fix secure storage access exception handling

Christian Borntraeger
2021-01-20T14:40:02Z

On 20.01.21 14:42, Heiko Carstens wrote:
> On Tue, Jan 19, 2021 at 11:25:01AM +0100, Christian Borntraeger wrote:
>>> + if (user_mode(regs)) {
>>> + send_sig(SIGSEGV, current, 0);
>>> + return;
>>> + } else
>>> + panic("Unexpected PGM 0x3d with TEID bit 61=0");
>>
>> use BUG instead of panic? That would kill this process, but it allows
>> people to maybe save unaffected data.
>
> It would kill the process, and most likely lead to deadlock'ed
> system. But with all the "good" debug information being lost, which
> wouldn't be the case with panic().
> I really don't think this is a good idea.
>

My understanding is that Linus hates panic for anything that might be able
to continue to run. With BUG the admin can decide via panic_on_oops if
debugging data or runtime data is more important. But mm is more on your
side, so if you insist on panic we can keep it.