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<div class="moz-cite-prefix">On 1/26/2016 9:43 PM, Dan Williams
wrote:<br>
</div>
<blockquote
cite="mid:CAPcyv4hmVKWjWG+q9v0Kx9M=GKG+HD0mwaGmAkf2we_GkpV7SA@mail.gmail.com"
type="cite">
<pre wrap="">On Mon, Jan 25, 2016 at 12:35 PM, Julian Margetson <a class="moz-txt-link-rfc2396E" href="mailto:runaway@candw.ms"><runaway@candw.ms></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">On 1/25/2016 3:20 PM, Dan Williams wrote:
</pre>
</blockquote>
<pre wrap="">[..]
</pre>
<blockquote type="cite">
<pre wrap="">Hmm, this commit could only cause a behavior change if it modifies the
value of the pfn as seen by insert_pfn(). Can you try the attached
debug patch to see if that assumption is being violated?
Had to manually delete the lines in the second part of the patch.
</pre>
</blockquote>
<pre wrap="">
Sorry about that I had based direct on that failing commit rather than
4.5-rc1. A reflowed version in the attached.
</pre>
<blockquote type="cite">
<pre wrap="">[ 42.557813] Oops: Machine check, sig: 7 [#1]
[ 42.562350] PREEMPT Canyonlands
[ 42.565692] Modules linked in:
[ 42.568933] CPU: 0 PID: 495 Comm: Xorg Tainted: G W
4.5.0-rc1-Sam460ex #1
[ 42.577291] task: ee3adcc0 ti: ee260000 task.ti: ee260000
[ 42.582984] NIP: 1ff72480 LR: 1ff72404 CTR: 1ff724d0
[ 42.588220] REGS: ee261f10 TRAP: 0214 Tainted: G W
(4.5.0-rc1-Sam460ex)
[ 42.596663] MSR: 0002d000 <CE,EE,PR,ME> CR: 24004242 XER: 00000000
[ 42.603512]
GPR00: 1f436134 bfc4dac0 b79cb6f0 b718dffc b69a4008 00000780 00000004
00000000
GPR08: 00000000 b718dffc 00000000 bfc4da70 1ff72404 2080dff4 00000000
00000780
GPR16: 00000000 00000020 00000000 00000000 00001e00 20aaa620 00000438
b69a4008
GPR24: 00000780 bfc4db18 20a94760 b718e000 b718e000 b69a4008 2007aff4
00001e00
[ 42.635363] NIP [1ff72480] 0x1ff72480
[ 42.639225] LR [1ff72404] 0x1ff72404
[ 42.642991] Call Trace:
[ 42.798393] ---[ end trace 8fcfa5f0e9942055 ]---
</pre>
</blockquote>
<pre wrap="">
I'm not familiar with powerpc crash dumps, so there's not much
information I can glean from this. Any folks on the cc can translate
a powerpc "Machine check"?
I'm down to looking a differences between the passing and failing
case. Can you print out the value the pte entry and the in
insert_pfn, like the following:
diff --git a/mm/memory.c b/mm/memory.c
index 30991f83d0bf..c44e387130b2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1521,6 +1521,8 @@ static int insert_pfn(struct vm_area_struct
*vma, unsigned long addr,
entry = pte_mkdevmap(pfn_t_pte(pfn, prot));
else
entry = pte_mkspecial(pfn_t_pte(pfn, prot));
+ pr_info("%s: entry: %#llx pfn: %#lx\n", __func__,
+ (unsigned long long) entry, pfn_t_to_pfn(pfn));
set_pte_at(mm, addr, pte, entry);
update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
...of course for the passing case you'll need to drop the call to
pfn_t_to_pfn() and just print the pfn directly.
Thank you for the help tracking this down, it's much appreciated.
</pre>
</blockquote>
Happy to help out. Just need some guidance sometimes as I am
relatively new at this.<br>
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<pre class="western">-----------------------------------------------------------------------------------------------------------------------------
15.802615] systemd[1]: Started Journal Service.
[ 44.263074] Oops: Machine check, sig: 7 [#1]
[ 44.267603] PREEMPT Canyonlands
[ 44.270938] Modules linked in:
[ 44.274182] CPU: 0 PID: 586 Comm: Xorg Tainted: G W 4.5.0-rc1-Sam460ex #2
[ 44.282538] task: ecd505c0 ti: efff2000 task.ti: ecd76000
[ 44.288239] NIP: c0000cec LR: 1fb81404 CTR: 1fb814d0
[ 44.293483] REGS: efff3f10 TRAP: 0214 Tainted: G W (4.5.0-rc1-Sam460ex)
[ 44.301926] MSR: 00021000 <CE,ME> CR: 84004242 XER: 00000000
[ 44.308185]
GPR00: 1f045134 bfd0ce80 b7e7b6f0 b763dffc b6e54008 00000780 00000004 00000000
GPR08: 00000000 b763dffc b6e54010 ecf50000 ecf50000 00000009 00000000 00000780
GPR16: 00000000 00000020 00000000 00000000 00001e00 2079b638 00000438 b6e54008
GPR24: 00000780 bfd0ced8 20785770 b763e000 b763e000 b6e54008 1fc89ff4 00001e00
[ 44.340039] NIP [c0000cec] DataTLBError44x+0x6c/0x90
[ 44.345279] LR [1fb81404] 0x1fb81404
[ 44.349053] Call Trace:
[ 44.351631] Instruction dump:
[ 44.354776] 7d7342a6 816b0040 7d92eaa6 7db00aa6 51ac063e 7d92eba6 7d9e0aa6 39a00009
[ 44.363081] 518d57bc 554c6cfa 7d6c582e 556c0029 <4182003c> 514cbd38 816c0000 818c0004
[ 44.524699] ---[ end trace 439fa29153308785 ]---
[ 44.529322]
[ 47.216536] insert_pfn: entry: 0x80ed246b pfn: 0x80ed2
[ 47.221777] insert_pfn: entry: 0x80ed346b pfn: 0x80ed3
[ 47.228485] insert_pfn: entry: 0x80ed446b pfn: 0x80ed4
[ 47.237798] insert_pfn: entry: 0x80ed546b pfn: 0x80ed5
[ 47.249809] insert_pfn: entry: 0x80ed646b pfn: 0x80ed6
[ 47.257588] insert_pfn: entry: 0x80ed746b pfn: 0x80ed7
[ 47.265879] insert_pfn: entry: 0x80ed846b pfn: 0x80ed8
[ 47.275825] insert_pfn: entry: 0x80ed946b pfn: 0x80ed9
[ 47.281437] insert_pfn: entry: 0x80eda46b pfn: 0x80eda
[ 47.288113] insert_pfn: entry: 0x80edb46b pfn: 0x80edb
[ 47.293660] insert_pfn: entry: 0x80edc46b pfn: 0x80edc
[ 47.299834] insert_pfn: entry: 0x80edd46b pfn: 0x80edd
[ 47.305223] insert_pfn: entry: 0x80ede46b pfn: 0x80ede
[ 47.314891] insert_pfn: entry: 0x80edf46b pfn: 0x80edf
[ 47.329777] insert_pfn: entry: 0x80ee046b pfn: 0x80ee0
[ 47.339769] insert_pfn: entry: 0x80ee146b pfn: 0x80ee1
[ 47.349777] Machine check in kernel mode.
[ 47.353814] Data Write PLB Error
[ 47.357049] Vector: 214 at [efff3f10]
[ 47.360799] pc: c0000cec: DataTLBError44x+0x6c/0x90
[ 47.366085] lr: 2008f404
[ 47.369002] sp: bfe76110
[ 47.371885] msr: 21000
[ 47.374506] current = 0xeced85c0
[ 47.377910] pid = 668, comm = Xorg
[ 47.381835] Linux version 4.5.0-rc1-Sam460ex (root@julian-VirtualBox) (gcc version 4.8.2 (Ubuntu 4.8.2-16ubuntu3) ) #2 PREEMPT Wed Jan 27 06:07:01 AST 2016
[ 47.395758] enter ? for help
[ 47.398638] mon> <no input ...>
[ 49.401927] Oops: Machine check, sig: 7 [#2]
[ 49.406450] PREEMPT Canyonlands
[ 49.409783] Modules linked in:
[ 49.413026] CPU: 0 PID: 668 Comm: Xorg Tainted: G D W 4.5.0-rc1-Sam460ex #2
[ 49.421383] task: eced85c0 ti: efff2000 task.ti: ecf8c000
[ 49.427075] NIP: c0000cec LR: 2008f404 CTR: 2008f4d0
[ 49.432311] REGS: efff3f10 TRAP: 0214 Tainted: G D W (4.5.0-rc1-Sam460ex)
[ 49.440755] MSR: 00021000 <CE,ME> CR: 88004262 XER: 00000000
[ 49.447013]
GPR00: 1f553134 bfe76110 b7d6d6f0 b752fffc b6d46008 00000780 00000004 00000000
GPR08: 00000000 b752fffc b6d46010 ecef9000 ecef9000 00000009 00000000 00000780
GPR16: 00000000 00000020 00000000 00000000 00001e00 20eb5650 00000438 b6d46008
GPR24: 00000780 bfe76168 20e9f728 b7530000 b7530000 b6d46008 20197ff4 00001e00
[ 49.478867] NIP [c0000cec] DataTLBError44x+0x6c/0x90
[ 49.484108] LR [2008f404] 0x2008f404
[ 49.487881] Call Trace:
[ 49.490460] Instruction dump:
[ 49.493603] 7d7342a6 816b0040 7d92eaa6 7db00aa6 51ac063e 7d92eba6 7d9e0aa6 39a00009
[ 49.501909] 518d57bc 554c6cfa 7d6c582e 556c0029 <4182003c> 514cbd38 816c0000 818c0004
[ 49.510404] ---[ end trace 439fa29153308786 ]---
[ 49.515026]</pre>
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