On Thu, Aug 07, 2014 at 10:00:25AM +0200, Pavel Machek wrote: > Hi! > > > > When the machine doesn't well handle the e820 persistent when hibernate > > > resuming, then it may causes page fault when writing image to snapshot > > > buffer: > > > > > > [ 17.929495] BUG: unable to handle kernel paging request at > > > ffff880069d4f000 > > > [ 17.933469] IP: [<ffffffff810a1cf0>] load_image_lzo+0x810/0xe40 > > > [ 17.933469] PGD 2194067 PUD 77ffff067 PMD 2197067 PTE 0 > > > [ 17.933469] Oops: 0002 [#1] SMP [...] > > > [ 8.933534] PM: Failed to load hibernation image, recovering. > > > > > > v2: > > > + removed empty check of nosave_regions list. > > > + fixed the typo of "region" in code for error message and patch comment. > > > > > > Cc: "Rafael J. Wysocki" <r...@rjwysocki.net> > > > Cc: Len Brown <len.br...@intel.com> > > > Cc: Takashi Iwai <ti...@suse.de> > > > Acked-by: Pavel Machek <pa...@ucw.cz> > > > Signed-off-by: Lee, Chun-Yi <j...@suse.com> > > > > I discussed with Vojtech Pavlik for this patch, he raised a situation is: > > > > Maybe e820 changed but image kernel original pages do not fall into new > > e820 region. > > Then the hibernate will recovery success, but later kernel drivers may got > > problem > > when accessing memory. > > > > My idea is hashing the start/end pfn of each nosave region sequentially, > > put this > > nosave region digest to hibernate header then compare e820 digest in > > check_header() > > when hibernate resuming. > > > > I am developing patch, then we don't need check unsafe page should not in > > unsave(e820) > > regions. > > Actually, if you are doing such a check... it makes sense to check for > _all_ the regions, nosave or not. If e820 map changed at all, it is > not safe to resume. > Pavel
Currently nosave region only called register by e820 code, so hibernate's nosave region included e820 reserved, ACPI data and ACPI NVS region. I thought hashing the start/end pfn of above regions is enough. Regards Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
