On 05-03 01:29, Rafael J. Wysocki wrote: > On Thursday, May 02, 2013 08:32:30 PM Jonas Heinrich wrote: > > On 05-02 02:45, Rafael J. Wysocki wrote: > > > On Wednesday, May 01, 2013 11:55:10 AM H. Peter Anvin wrote: > > > > On 05/01/2013 11:51 AM, Jonas Heinrich wrote: > > > > > Well, you could give me instructions on how to debug this (I'll do > > > > > everything ;)) or I could ship you the Thinkpad T43. I guess this > > > > > would worth the effort since this bug is somehow critical. > > > > > > > > > > Best regards, Jonas > > > > > > > > I'll put together a debug patch unless I can trick Rafael into doing > > > > it first... > > > > > > I'm afraid that code has changed quite a bit since I looked at it last > > > time. > > > [Jarkko Sakkinen seems to have worked on it lately, CCed.] > > > > > > Jonas, I wonder what happens if you drop the first hunk of the patch (it > > > just > > > uses a different register, which shouldn't matter)? Does it still help > > > then? > > > > Hello Rafel, first of all, thank you for helping me out :) > > You're right, the patch still solves the suspend bug, after removing the > > first > > hunk of the patch and applying it (see attachement: > > suspendfix_first_hunk_dropped.patch). > > > > > > > > If so, there are still a few things you can do to it, e.g: > > > (1) drop the > > > > > > - btl $WAKEUP_BEHAVIOR_RESTORE_CR4, %edi > > > - jnc 1f > > > > > > > Still works :) (used suspendfix_1.patch) > > > > > lines, > > > (2) drop the > > > > > > - btl $WAKEUP_BEHAVIOR_RESTORE_EFER, %edi > > > - jnc 1f > > > > > > lines, > > > > Still works :) (used suspendfix_2.patch) > > > > > (3) drop the > > > > > > + jecxz 1f > > > > > > > Still works :) (used suspendfix_3.patch) > > > > > line, > > > (4) drop the > > > > > > + movl %eax, %ecx > > > + orl %edx, %ecx > > > + jz 1f > > > > > > > At this point, the bug reoccurs (used suspendfix_4.patch)! > > But that doesn't mean these lines are the only critical, because the more > > minimal patch > > > > @@ -119,6 +119,9 @@ > > jnc 1f > > movl pmode_efer, %eax > > movl pmode_efer + 4, %edx > > + movl %eax, %ecx > > + orl %edx, %ecx > > + jz 1f > > movl $MSR_EFER, %ecx > > wrmsr > > 1: > > > > > > with removing this part > > > > - movl pmode_cr4, %eax > > - movl %eax, %cr4 > > + movl pmode_cr4, %ecx > > + movl %ecx, %cr4 > > > > also doesn't fix the issue (see suspendfix_5.patch). > > > > > lines and see what the minimal patch needed for things to work again is. > > > > > > > So the most minimal working patch is suspendfix_3.patch. > > Thanks for doing that detective work! > > The only explanation of why this particular patch can help that seems viable > to > us at the moment is that we have a memory corruption in the code region > modified > by it and the patch simply changes the alignment of the instructions that > don't > get corrupted. > > It looks like this may be verified by putting a bunch of nops into the region > in question, so can you please check if the attached patch helps too?
Unfortunately, your attached patch doesn't seem to fix the bug. Hope you still have some ideas to address this issue :) - Jonas > > Rafael > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center.
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