On Thu, Aug 27, 2020 at 3:53 PM Laurent Dufour wrote:
>
> Le 10/08/2020 à 10:52, Pingfan Liu a écrit :
> > A bug is observed on pseries by taking the following steps on rhel:
> > -1. drmgr -c mem -r -q 5
> > -2. echo c > /proc/sysrq-trigger
> >
> > And then, the failure looks like:
> > kdump: savi
This is an attempt to fix a few different related issues around
switching mm, TLB flushing, and lazy tlb mm handling.
This will require all architectures to eventually move to disabling
irqs over activate_mm, but it's possible we could add another arch
call after irqs are re-enabled for those few
Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing an intermediate
state.
This is similar to commit 38cf307c1f20 ("mm: fix kthread_use_mm() vs TLB
invalidate"). At exec-time when the new mm is activated, the old one
shoul
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/i
The de facto (and apparently uncommented) standard for using an mm had,
thanks to this code in sparc if nothing else, been that you must have a
reference on mm_users *and that reference must have been obtained with
mmget()*, i.e., from a thread with a reference to mm_users that had used
the mm.
Th
Commit 0cef77c7798a7 ("powerpc/64s/radix: flush remote CPUs out of
single-threaded mm_cpumask") added a mechanism to trim the mm_cpumask of
a process under certain conditions. One of the assumptions is that
mm_users would not be incremented via a reference outside the process
context with mmget_not
If the hypervisor doesn't support hugepages, the kernel ends up allocating a
large
number of page table pages. The early page table allocation was wrongly
setting the max memblock limit to ppc64_rma_size with radix translation
which resulted in boot failure as shown below.
Kernel panic - not sync
On Fri, Aug 28, 2020 at 08:00:19PM +1000, Nicholas Piggin wrote:
> Closing this race only requires interrupts to be disabled while ->mm
> and ->active_mm are being switched, but the TLB problem requires also
> holding interrupts off over activate_mm. Unfortunately not all archs
> can do that yet,
On Mon, 2020-08-24 at 13:44 +1000, Alexey Kardashevskiy wrote:
>
> > On 18/08/2020 09:40, Leonardo Bras wrote:
> > enable_ddw() currently returns the address of the DMA window, which is
> > considered invalid if has the value 0x00.
> >
> > Also, it only considers valid an address returned from fi
On Mon, 2020-08-24 at 15:07 +1000, Alexey Kardashevskiy wrote:
>
> On 18/08/2020 09:40, Leonardo Bras wrote:
> > Code used to create a ddw property that was previously scattered in
> > enable_ddw() is now gathered in ddw_property_create(), which deals with
> > allocation and filling the property,
-20200827
x86_64 randconfig-a006-20200827
x86_64 randconfig-a004-20200827
i386 randconfig-a002-20200828
i386 randconfig-a005-20200828
i386 randconfig-a003-20200828
i386 randconfig-a004-20200828
i386
allyesconfig
mips allmodconfig
powerpc defconfig
powerpc allyesconfig
powerpc allmodconfig
i386 randconfig-a002-20200828
i386 randconfig-a005-20200828
i
randconfig-a006-20200827
x86_64 randconfig-a004-20200827
i386 randconfig-a002-20200828
i386 randconfig-a005-20200828
i386 randconfig-a003-20200828
i386 randconfig-a004-20200828
i386 randconfig-a001-20200828
On Tue, Aug 18, 2020 at 05:08:16PM +0100, Will Deacon wrote:
> On Tue, Aug 18, 2020 at 04:07:36PM +0100, Matthew Wilcox wrote:
> > For example, arm64 seems confused in this scenario:
> >
> > void flush_dcache_page(struct page *page)
> > {
> > if (test_bit(PG_dcache_clean, &page->flags))
>
On Thu, Aug 27, 2020 at 12:39:06PM +0200, Christophe Leroy wrote:
> Hi,
>
> Le 27/08/2020 à 10:28, Giuseppe Sacco a écrit :
> > Il giorno gio, 27/08/2020 alle 09.46 +0200, Giuseppe Sacco ha scritto:
> > > Il giorno gio, 27/08/2020 alle 00.28 +0200, Giuseppe Sacco ha scritto:
> > > > Hello Christop
On Mon, 2020-08-24 at 15:17 +1000, Alexey Kardashevskiy wrote:
>
> On 18/08/2020 09:40, Leonardo Bras wrote:
> > As of today, if the biggest DDW that can be created can't map the whole
> > partition, it's creation is skipped and the default DMA window
> > "ibm,dma-window" is used instead.
> >
> >
On Fri, 2020-08-28 at 12:27 +1000, Alexey Kardashevskiy wrote:
>
> On 28/08/2020 01:32, Leonardo Bras wrote:
> > Hello Alexey, thank you for this feedback!
> >
> > On Sat, 2020-08-22 at 19:33 +1000, Alexey Kardashevskiy wrote:
> > > > +#define TCE_RPN_BITS 52 /* Bits 0-51 r
On Fri, 2020-08-28 at 11:40 +1000, Alexey Kardashevskiy wrote:
> > I think it would be better to keep the code as much generic as possible
> > regarding page sizes.
>
> Then you need to test it. Does 4K guest even boot (it should but I would
> not bet much on it)?
Maybe testing with host 64k pag
On Fri, 2020-08-28 at 11:58 +1000, Alexey Kardashevskiy wrote:
>
> On 28/08/2020 08:11, Leonardo Bras wrote:
> > On Mon, 2020-08-24 at 13:46 +1000, Alexey Kardashevskiy wrote:
> > > > static int find_existing_ddw_windows(void)
> > > > {
> > > > int len;
> > > > @@ -887,18 +905,11 @@ stat
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