On Thu, Nov 9, 2017 at 4:46 PM, Thomas Gleixner <[email protected]> wrote: > On Fri, 10 Nov 2017, Arnd Bergmann wrote: >> On Fri, Nov 10, 2017 at 12:00 AM, Thomas Gleixner <[email protected]> wrote: >> > Hmm, no. None of the regular accessor functions can be called from NMI >> > context safely. >> >> Right, that's what I mean: it must not get called from NMI context, but it >> currently is, at least for this case: >> >> NMI handler: >> something bad >> panic() >> kmsg_dump() >> pstore_dump() >> pstore_record_init() >> __getnstimeofday() >> >> I should probably add that to the changelog text ;-) > > Indeed.
Er, so, is this safe to call there? I've had to fix this a few times now, so if using ktime_get_real_fast_ns() can be used here (and doesn't return 0) then this is easily an improvement over the existing "maybe read 0" case pstore has now. -Kees -- Kees Cook Pixel Security
