On 07/30/2014 16:26, Andreas Tobler wrote:
> On 30.07.14 23:17, Alan Cox wrote:
>> On 07/30/2014 15:15, Andreas Tobler wrote:
>>> On 30.07.14 21:54, Alan Cox wrote:
>>>> On 07/30/2014 14:46, Alan Cox wrote:
>>>>> On 07/30/2014 13:58, Andreas Tobler wrote:
>>>>>> Hi Alan,
>>>>>>
>>>>>> On 26.07.14 20:10, Alan Cox wrote:
>>>>>>> Author: alc
>>>>>>> Date: Sat Jul 26 18:10:18 2014
>>>>>>> New Revision: 269134
>>>>>>> URL: http://svnweb.freebsd.org/changeset/base/269134
>>>>>>>
>>>>>>> Log:
>>>>>>> When unwiring a region of an address space, do not assume that
>>>>>>> the
>>>>>>> underlying physical pages are mapped by the pmap. If, for
>>>>>>> example, the
>>>>>>> application has performed an mprotect(..., PROT_NONE) on
>>>>>>> any part
>>>>>>> of the
>>>>>>> wired region, then those pages will no longer be mapped by the
>>>>>>> pmap.
>>>>>>> So, using the pmap to lookup the wired pages in order to
>>>>>>> unwire them
>>>>>>> doesn't always work, and when it doesn't work wired pages are
>>>>>>> leaked.
>>>>>>>
>>>>>>> To avoid the leak, introduce and use a new function
>>>>>>> vm_object_unwire()
>>>>>>> that locates the wired pages by traversing the object and its
>>>>>>> backing
>>>>>>> objects.
>>>>>>>
>>>>>>> At the same time, switch from using pmap_change_wiring() to
>>>>>>> the
>>>>>>> recently
>>>>>>> introduced function pmap_unwire() for unwiring the region's
>>>>>>> mappings.
>>>>>>> pmap_unwire() is faster, because it operates a range of
>>>>>>> virtual
>>>>>>> addresses
>>>>>>> rather than a single virtual page at a time. Moreover, by
>>>>>>> operating on
>>>>>>> a range, it is superpage friendly. It doesn't waste time
>>>>>>> performing
>>>>>>> unnecessary demotions.
>>>>>>>
>>>>>>> Reported by: markj
>>>>>>> Reviewed by: kib
>>>>>>> Tested by: pho, jmg (arm)
>>>>>>> Sponsored by: EMC / Isilon Storage Division
>>>>>> This commit brings my 32- and 64-bit PowerMac's into panic.
>>>>>> Unfortunately I'm not able to give you a backtrace in the form of a
>>>>>> textdump nor of a core dump.
>>>>>>
>>>>>> The only thing I have is this picture:
>>>>>>
>>>>>> http://people.freebsd.org/~andreast/r269134_panic.jpg
>>>>>>
>>>>>> Exactly this revision gives a panic and breaks the textdump/coredump
>>>>>> facility.
>>>>>>
>>>>>> How can I help debugging?
>>>>>>
>>>>> It appears to me that moea64_pvo_enter() had a pre-existing bug that
>>>>> got
>>>>> tickled by this change. Specifically, moea64_pvo_enter() doesn't set
>>>>> the PVO_WIRED flag when an unwired mapping already exists. It just
>>>>> returns with the mapping still in an unwired state. Consequently,
>>>>> when
>>>>> pmap_unwire() finally runs, it doesn't find a wired mapping.
>>>>>
>>>>> Try this:
>>>>>
>>>>> Index: powerpc/aim/mmu_oea64.c
>>>>> ===================================================================
>>>>> --- powerpc/aim/mmu_oea64.c (revision 269127)
>>>>> +++ powerpc/aim/mmu_oea64.c (working copy)
>>>>> @@ -2274,7 +2274,8 @@ moea64_pvo_enter(mmu_t mmu, pmap_t pm,
>>>>> uma_zone_t
>>>>> if (pvo->pvo_pmap == pm && PVO_VADDR(pvo) == va) {
>>>>> if ((pvo->pvo_pte.lpte.pte_lo & LPTE_RPGN)
>>>>> == pa &&
>>>>> (pvo->pvo_pte.lpte.pte_lo &
>>>>> (LPTE_NOEXEC |
>>>>> LPTE_PP))
>>>>> - == (pte_lo & (LPTE_NOEXEC | LPTE_PP))) {
>>>>> + == (pte_lo & (LPTE_NOEXEC | LPTE_PP)) &&
>>>>> + ((pvo->pvo_vaddr ^ flags) & PVO_WIRED)) {
>>>>> if (!(pvo->pvo_pte.lpte.pte_hi &
>>>>> LPTE_VALID)) {
>>>>> /* Re-insert if spilled */
>>>>> i = MOEA64_PTE_INSERT(mmu,
>>>>> ptegidx,
>>>>>
>>>>
>>>> The new conditional test needs to be inverted. Try this instead:
>>>>
>>>> Index: powerpc/aim/mmu_oea64.c
>>>> ===================================================================
>>>> --- powerpc/aim/mmu_oea64.c (revision 269127)
>>>> +++ powerpc/aim/mmu_oea64.c (working copy)
>>>> @@ -2274,7 +2274,8 @@ moea64_pvo_enter(mmu_t mmu, pmap_t pm,
>>>> uma_zone_t
>>>> if (pvo->pvo_pmap == pm && PVO_VADDR(pvo) == va) {
>>>> if ((pvo->pvo_pte.lpte.pte_lo & LPTE_RPGN)
>>>> == pa &&
>>>> (pvo->pvo_pte.lpte.pte_lo &
>>>> (LPTE_NOEXEC |
>>>> LPTE_PP))
>>>> - == (pte_lo & (LPTE_NOEXEC | LPTE_PP))) {
>>>> + == (pte_lo & (LPTE_NOEXEC | LPTE_PP)) &&
>>>> + ((pvo->pvo_vaddr ^ flags) & PVO_WIRED) ==
>>>> 0) {
>>>> if (!(pvo->pvo_pte.lpte.pte_hi &
>>>> LPTE_VALID)) {
>>>> /* Re-insert if spilled */
>>>> i = MOEA64_PTE_INSERT(mmu,
>>>> ptegidx,
>>>>
>>>
>>>
>>> The panic stays, but the message is different:
>>>
>>> panic: moea64_pvo_to_pte: pvo 0x10147ea0 has invalid pte 0xb341180 in
>>> moea64_pteg_table but valid in pvo.
>>>
>>
>> My attempted fix is doing something else wrong. Do you have a stack
>> trace?
>
> iPhone sei Dank:
>
> http://people.freebsd.org/~andreast/r269134-1_panic.jpg
Ok, this patch should fix both the original panic and the new one. They
are two distinct problems.
Index: powerpc/aim/mmu_oea64.c
===================================================================
--- powerpc/aim/mmu_oea64.c (revision 269127)
+++ powerpc/aim/mmu_oea64.c (working copy)
@@ -1090,6 +1090,7 @@ moea64_unwire(mmu_t mmu, pmap_t pm, vm_offset_t sv
for (pvo = RB_NFIND(pvo_tree, &pm->pmap_pvo, &key);
pvo != NULL && PVO_VADDR(pvo) < eva;
pvo = RB_NEXT(pvo_tree, &pm->pmap_pvo, pvo)) {
+ pt = MOEA64_PVO_TO_PTE(mmu, pvo);
if ((pvo->pvo_vaddr & PVO_WIRED) == 0)
panic("moea64_unwire: pvo %p is missing PVO_WIRED",
pvo);
@@ -1098,7 +1099,7 @@ moea64_unwire(mmu_t mmu, pmap_t pm, vm_offset_t sv
panic("moea64_unwire: pte %p is missing LPTE_WIRED",
&pvo->pvo_pte.lpte);
pvo->pvo_pte.lpte.pte_hi &= ~LPTE_WIRED;
- if ((pt = MOEA64_PVO_TO_PTE(mmu, pvo)) != -1) {
+ if (pt != -1) {
/*
* The PTE's wired attribute is not a hardware
* feature, so there is no need to invalidate any TLB
@@ -2274,7 +2275,8 @@ moea64_pvo_enter(mmu_t mmu, pmap_t pm, uma_zone_t
if (pvo->pvo_pmap == pm && PVO_VADDR(pvo) == va) {
if ((pvo->pvo_pte.lpte.pte_lo & LPTE_RPGN) == pa &&
(pvo->pvo_pte.lpte.pte_lo & (LPTE_NOEXEC | LPTE_PP))
- == (pte_lo & (LPTE_NOEXEC | LPTE_PP))) {
+ == (pte_lo & (LPTE_NOEXEC | LPTE_PP)) &&
+ ((pvo->pvo_vaddr ^ flags) & PVO_WIRED) == 0) {
if (!(pvo->pvo_pte.lpte.pte_hi & LPTE_VALID)) {
/* Re-insert if spilled */
i = MOEA64_PTE_INSERT(mmu, ptegidx,
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