[BUG] v4.12 breaks pxa25x

Russell King - ARM Linux [off-list ref] writes:

On Mon, Jul 17, 2017 at 08:41:03AM +0200, Robert Jarzmik wrote:

quoted

[    0.000000] Unhandled fault: alignment exception (0x003) at 0xc06f82cd
[    0.000000] pgd = c0004000
[    0.000000] [c06f82cd] *pgd=a060040e(bad)
[    0.000000] Internal error: : 3 [#1] ARM
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.12.0-11927-g6bf3d68 #4582
[    0.000000] Hardware name: Intel DBPXA250 Development Platform (aka Lubbock)
[    0.000000] task: c06f6fd8 task.stack: c06f2000
[    0.000000] PC is at __flush_whole_cache+0x4/0x60
[    0.000000] LR is at paging_init+0x4b4/0x590
[    0.000000] pc : [<c0019e24>]    lr : [<c049d274>]    psr: 600000d3
[    0.000000] sp : c06f3f38  ip : 00000000  fp : c0700000
[    0.000000] r10: a4000000  r9 : c06f82c0  r8 : c0723540
[    0.000000] r7 : fe100000  r6 : fe200000  r5 : c06f82a0  r4 : c0705ef4
[    0.000000] r3 : 00000000  r2 : 00000004  r1 : c06f82cd  r0 : c06f82c0

Looks like the .data section has become misaligned somehow.  r1 is the
address of "clean_addr" which is clearly not 32-bit aligned.

Please can you check in System.map to see what's immediately before it?

Sure, it like this :
c06f22c8 D user_pmd_table
c06f22cc d __warned.19178
c06f22cd d clean_addr

And I have no idea how to link that __warned.19178 with the WARN_xxx() statement ...

This bisection I made points me to :
# first bad commit: [799c43415442414b1032580c47684cb709dfed6d] kbuild: thin archives make default for all archs

Reverting this commit makes my kernel boot again.

--
Robert