Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers

[Christophe Leroy]

Le 12/09/2019 Ã 17:36, Christophe Leroy a ÃcritÂ:
> Le 12/09/2019 Ã 17:00, Christophe Leroy a ÃcritÂ:
> > On 09/12/2019 06:02 AM, Anshuman Khandual wrote:
> > > This adds a test module which will validate architecture page table 
> > > helpers
> > > and accessors regarding compliance with generic MM semantics 
> > > expectations.
> > > This will help various architectures in validating changes to the 
> > > existing
> > > page table helpers or addition of new ones.
> > >
> > > Test page table and memory pages creating it's entries at various 
> > > level are
> > > all allocated from system memory with required alignments. If memory 
> > > pages
> > > with required size and alignment could not be allocated, then all 
> > > depending
> > > individual tests are skipped.
> >
> > Build failure on powerpc book3s/32. This is because asm/highmem.h is 
> > missing. It can't be included from asm/book3s/32/pgtable.h because it 
> > creates circular dependency. So it has to be included from 
> > mm/arch_pgtable_test.c
>
> In fact it is <linux/highmem.h> that needs to be added, adding 
> <asm/highmem.h> directly provokes build failure at link time.

I get the following failure,

[    0.704685] ------------[ cut here ]------------
[    0.709239] initcall arch_pgtable_tests_init+0x0/0x228 returned with 
preemption imbalance
[    0.717539] WARNING: CPU: 0 PID: 1 at init/main.c:952 
do_one_initcall+0x18c/0x1d4
[    0.724922] CPU: 0 PID: 1 Comm: swapper Not tainted 
5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307
[    0.734070] NIP:  c070e674 LR: c070e674 CTR: c001292c
[    0.739084] REGS: df4a5dd0 TRAP: 0700   Not tainted 
(5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty)
[    0.747975] MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 28000222  XER: 00000000
[    0.754628]
[    0.754628] GPR00: c070e674 df4a5e88 df4a0000 0000004e 0000000a 
00000000 000000ca 38207265
[    0.754628] GPR08: 00001032 00000800 00000000 00000000 22000422 
00000000 c0004a7c 00000000
[    0.754628] GPR16: 00000000 00000000 00000000 00000000 00000000 
c0810000 c0800000 c0816f30
[    0.754628] GPR24: c070dc20 c074702c 00000006 0000009c 00000000 
c0724494 c074e140 00000000
[    0.789339] NIP [c070e674] do_one_initcall+0x18c/0x1d4
[    0.794435] LR [c070e674] do_one_initcall+0x18c/0x1d4
[    0.799437] Call Trace:
[    0.801867] [df4a5e88] [c070e674] do_one_initcall+0x18c/0x1d4 
(unreliable)
[    0.808694] [df4a5ee8] [c070e8c0] kernel_init_freeable+0x204/0x2dc
[    0.814830] [df4a5f28] [c0004a94] kernel_init+0x18/0x110
[    0.820107] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c
[    0.826220] Instruction dump:
[    0.829161] 4beb1069 7d2000a6 61298000 7d200124 89210008 2f890000 
41be0048 3c60c06a
[    0.836849] 38a10008 7fa4eb78 3863cacc 4b915115 <0fe00000> 4800002c 
81220070 712a0004
[    0.844723] ---[ end trace 969d686308d40b33 ]---

Then starting init fails:

[    3.894074] Run /init as init process
[    3.898403] Failed to execute /init (error -14)
[    3.903009] Run /sbin/init as init process
[    3.907172] Run /etc/init as init process
[    3.911251] Run /bin/init as init process
[    3.915513] Run /bin/sh as init process
[    3.919471] Starting init: /bin/sh exists but couldn't execute it 
(error -14)
[    3.926732] Kernel panic - not syncing: No working init found.  Try 
passing init= option to kernel. See Linux 
Documentation/admin-guide/init.rst for guidance.
[    3.940864] CPU: 0 PID: 1 Comm: init Tainted: G        W 
5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307
[    3.951165] Call Trace:
[    3.953617] [df4a5ec8] [c002392c] panic+0x12c/0x320 (unreliable)
[    3.959621] [df4a5f28] [c0004b8c] rootfs_mount+0x0/0x2c
[    3.964849] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c


Christophe