Hi,
I would like to add this bug bit me too. I am on a Dell XPS 13 9350
(Skylake, late 2015 model). So far, all 4.4.0 kernel packages from
Unstable hang at boot (ie 4.4.2-1 through -3). Booting in UEFI mode,
CSM disabled.
I had built my own kernel based on a 4.4.0 config from an earlier
Experimental build (RC8) and updated that on every patchlevel release,
still works fine (on 4.4.3 now).
The efi=noruntime boot argument does the trick for me; the 4.4.2
testing package Ben uploaded however still hangs, just like the 4.5 RC4
package from Experimental.
Can test/provide more info if needed.
Cheers
Stijn Segers
On Tue, 23 Feb 2016 20:17:03 +0100 Alexis Murzeau <amub...@gmail.com>
wrote:
> Hi,
>
> I have the same traceback as Zdravko in Message #121 (NULL pointer
> dereference at RIP=0xffffffff81063682,
__change_page_attr_set_clr+0x242).
>
> If I add "efi=old_map" parameter to kernel cmdline, the kernel boots
> fine.
>
> Also, this might help Norbert to have a traceback printed: using
> "quiet earlyprintk=efi,keep" kernel cmdline options will print only
> the traceback (so it should be faster to get the kernel to the crash
> traceback, if the cause is really a crash).
>
>
> After compiling several kernels, I narrowed down the crash to the
> patch "x86-efi-build-our-own-page-table-structures.patch".
>
> Without this patch, the kernel boots fine (dmesg output in attachment
> dmesg_linux-4.4.2_[...].txt)
>
> With this patch, I get the crash in efi_call (photo of
> "earlyprintk=efi,keep" output in attachment
> traceback_linux-4.4.2_with_patch_[...].jpg).
>
> I also added 4 printk to add information before the crash when
> calling efi_call_phys with efi_phys.set_virtual_address_map (see also
> "additionnal_printk.diff" in attachment). (Not sure if it can help)
>
> When I added these printk, the traceback stop at efi_call
> (__change_page_attr_set_clr isn't anymore in the traceback) but RIP
> is still the same as without these changes.
>
> See also the traceback I get in attachment
> traceback_linux-4.4.2-3_unmodified.jpg with the current 4.4 kernel
> (version 4.4.2-3 unmodified)
>
> Also, let me know if a new bug should be opened for this.
>
> Thanks,
> Alexis Murzeau
