> -----Original Message----- > From: Pavel Machek [mailto:pa...@ucw.cz] > Sent: Sunday, August 28, 2016 9:15 PM > To: Chen, Yu C > Cc: joeyli; Rafael J. Wysocki; linux...@vger.kernel.org; linux- > ker...@vger.kernel.org > Subject: Re: [PATCH][v6] PM / hibernate: Print the possible panic reason when > resuming with inconsistent e820 map > > On Sun 2016-08-28 13:08:02, Chen, Yu C wrote: > > > -----Original Message----- > > > From: Pavel Machek [mailto:pa...@ucw.cz] > > > Sent: Sunday, August 28, 2016 8:48 PM > > > To: Chen, Yu C > > > Cc: joeyli; Rafael J. Wysocki; linux...@vger.kernel.org; linux- > > > ker...@vger.kernel.org > > > Subject: Re: [PATCH][v6] PM / hibernate: Print the possible panic > > > reason when resuming with inconsistent e820 map > > > > > > On Sun 2016-08-28 10:07:10, Chen Yu wrote: > > > > Hi, > > > > On Fri, Aug 26, 2016 at 09:56:54PM +0200, Pavel Machek wrote: > > > > > Hi! > > > > > > > > > > > > > > What's the progress of this patch? Looks already have > > > > > > > > > experts > > > review it. > > > > > > > > > Why this patch didn't accept? > > > > > > > > This patch is a little overkilled, and I have saved > > > > > > > > another simpler version to only check the md5 hash (as > > > > > > > > people suggested) for > > > it. I can post it later. > > > > > > > > > > > > > > > > > > > > > > I am happy to test and review it. > > > > > > > > > > > > > Here it is. As Rafael is on travel, it would be grateful if > > > > > > you can give some advance on this, thanks! > > > > > > > > > > Better than last one. > > > > > > > > > > > + return -ENOMEM; > > > > > > + > > > > > > + req = ahash_request_alloc(tfm, GFP_ATOMIC); > > > > > > > > > > what context is this called from? GFP_ATOMIC allocations like to > > > > > fail... > > > > > > > > > It is in normal process context, OK, I'll change it to GFP_KERNEL. > > > > > > +static int hibernation_e820_check(void *buf) { > > > > > > + int ret; > > > > > > + char result[MD5_HASH_SIZE] = {0}; > > > > > > + > > > > > > + ret = get_e820_md5(&e820_saved, result); > > > > > > + if (ret) > > > > > > + return ret; > > > > > > + > > > > > > + if (memcmp(result, buf, MD5_HASH_SIZE)) > > > > > > + e820_conflict = true; > > > > > > > > > > Passing return value using global variable is ugly. Can you just > > > > > print the warning and kill the box here? > > > > Do you mean get rid of the panic hooker and just print the warning > > > > here? > > > > > > Yep, I'd do that... (And you probably want to rise the severity). > > Sometime the users might not be able to see the warning during > > resume(too fast) and got a system panic later, so I was thinking if it > > might help user to see the warning in panic too, how about this: > > > > if (memcmp(result, buf, MD5_DIGEST_SIZE)) { > > pr_err("PM: e820 map conflict detected!\n"); > > register_die_notifier(&hibernation_die_notifier); > > } > > So we can print warning in hibernation_die_notifier without introducing a > global variable? > > > > Actually, I'd kill the machine right away. > > if (memcmp(result, buf, MD5_DIGEST_SIZE)) { > pr_err("PM: e820 map conflict detected!\n"); > panic("BIOS is playing funny tricks with us.\n"); > } > OK, this is more reasonable, will take this one.
Thanks, Yu
