* [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE
@ 2017-05-05 6:31 Scott Wood
2017-05-08 14:09 ` Michael Ellerman
0 siblings, 1 reply; 4+ messages in thread
From: Scott Wood @ 2017-05-05 6:31 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Scott Wood, Aneesh Kumar K . V
Commit f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB") increased
the task size on book3s, and introduced a mechanism to dynamically
control whether a task uses these larger addresses. While the change to
the task size itself was ifdef-protected to only apply on book3s, the
change to STACK_TOP_USER64 was not. On book3e, this had the effect of
trying to use addresses up to 128TiB for the stack despite a 64TiB task
size limit -- which broke 64-bit userspace producing the following errors:
Starting init: /sbin/init exists but couldn't execute it (error -14)
Starting init: /bin/sh exists but couldn't execute it (error -14)
Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
Fixes: f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB")
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Scott Wood <oss@buserror.net>
---
arch/powerpc/include/asm/processor.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index a4b1d8d6b793..a2123f291ab0 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -151,8 +151,13 @@ void release_thread(struct task_struct *);
#ifdef __powerpc64__
+#ifdef CONFIG_PPC_BOOK3S_64
/* Limit stack to 128TB */
#define STACK_TOP_USER64 TASK_SIZE_128TB
+#else
+#define STACK_TOP_USER64 TASK_SIZE_USER64
+#endif
+
#define STACK_TOP_USER32 TASK_SIZE_USER32
#define STACK_TOP (is_32bit_task() ? \
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE
2017-05-05 6:31 [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE Scott Wood
@ 2017-05-08 14:09 ` Michael Ellerman
2017-05-08 15:52 ` Scott Wood
0 siblings, 1 reply; 4+ messages in thread
From: Michael Ellerman @ 2017-05-08 14:09 UTC (permalink / raw)
To: Scott Wood, linuxppc-dev; +Cc: Scott Wood, Aneesh Kumar K . V
Scott Wood <oss@buserror.net> writes:
> Commit f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB") increased
> the task size on book3s, and introduced a mechanism to dynamically
> control whether a task uses these larger addresses. While the change to
> the task size itself was ifdef-protected to only apply on book3s, the
> change to STACK_TOP_USER64 was not. On book3e, this had the effect of
> trying to use addresses up to 128TiB for the stack despite a 64TiB task
> size limit -- which broke 64-bit userspace producing the following errors:
>
> Starting init: /sbin/init exists but couldn't execute it (error -14)
> Starting init: /bin/sh exists but couldn't execute it (error -14)
> Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
For some reason I am not seeing this on my p5020ds?
I just checked, it's definitely booting:
[ 0.000000] Linux version 4.11.0-gcc5-g13e0988 (kerkins@alpine1-p1) (gcc version 5.2.1 20151001 (GCC) ) #1 SMP Mon May 8 05:33:22 AEST 2017
[ 0.000000] Using CoreNet Generic machine description
...
[ 3.216940] systemd[1]: Detected architecture ppc64.
...
Debian GNU/Linux stretch/sid p5020ds ttyS0
p5020ds login:
Anyway patch looks good, I'll pull it in with the rest of your tree.
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE
2017-05-08 14:09 ` Michael Ellerman
@ 2017-05-08 15:52 ` Scott Wood
2017-05-09 21:13 ` Michael Ellerman
0 siblings, 1 reply; 4+ messages in thread
From: Scott Wood @ 2017-05-08 15:52 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: Aneesh Kumar K . V
On Tue, 2017-05-09 at 00:09 +1000, Michael Ellerman wrote:
> Scott Wood <oss@buserror.net> writes:
>
> > Commit f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB") increased
> > the task size on book3s, and introduced a mechanism to dynamically
> > control whether a task uses these larger addresses. While the change to
> > the task size itself was ifdef-protected to only apply on book3s, the
> > change to STACK_TOP_USER64 was not. On book3e, this had the effect of
> > trying to use addresses up to 128TiB for the stack despite a 64TiB task
> > size limit -- which broke 64-bit userspace producing the following errors:
> >
> > Starting init: /sbin/init exists but couldn't execute it (error -14)
> > Starting init: /bin/sh exists but couldn't execute it (error -14)
> > Kernel panic - not syncing: No working init found. Try passing init=
> > option to kernel. See Linux Documentation/admin-guide/init.rst for
> > guidance.
>
> For some reason I am not seeing this on my p5020ds?
>
> I just checked, it's definitely booting:
>
> [ 0.000000] Linux version 4.11.0-gcc5-g13e0988 (kerkins@alpine1-p1)
> (gcc version 5.2.1 20151001 (GCC) ) #1 SMP Mon May 8 05:33:22 AEST 2017
> [ 0.000000] Using CoreNet Generic machine description
> ...
> [ 3.216940] systemd[1]: Detected architecture ppc64.
> ...
> Debian GNU/Linux stretch/sid p5020ds ttyS0
>
> p5020ds login:
>
>
> Anyway patch looks good, I'll pull it in with the rest of your tree.
Are you using a 64-bit userspace?
-Scott
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE
2017-05-08 15:52 ` Scott Wood
@ 2017-05-09 21:13 ` Michael Ellerman
0 siblings, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2017-05-09 21:13 UTC (permalink / raw)
To: Scott Wood, linuxppc-dev; +Cc: Aneesh Kumar K . V
Scott Wood <oss@buserror.net> writes:
> On Tue, 2017-05-09 at 00:09 +1000, Michael Ellerman wrote:
>> Scott Wood <oss@buserror.net> writes:
>>=20
>> > Commit f4ea6dcb08ea ("powerpc/mm: Enable mappings above 128TB") increa=
sed
>> > the task size on book3s, and introduced a mechanism to dynamically
>> > control whether a task uses these larger addresses.=C2=A0=C2=A0While t=
he change to
>> > the task size itself was ifdef-protected to only apply on book3s, the
>> > change to STACK_TOP_USER64 was not.=C2=A0=C2=A0On book3e, this had the=
effect of
>> > trying to use addresses up to 128TiB for the stack despite a 64TiB task
>> > size limit -- which broke 64-bit userspace producing the following err=
ors:
>> >=20
>> > Starting init: /sbin/init exists but couldn't execute it (error -14)
>> > Starting init: /bin/sh exists but couldn't execute it (error -14)
>> > Kernel panic - not syncing: No working init found.=C2=A0=C2=A0Try pass=
ing init=3D
>> > option to kernel. See Linux Documentation/admin-guide/init.rst for
>> > guidance.
>>=20
>> For some reason I am not seeing this on my p5020ds?
>>=20
>> I just checked, it's definitely booting:
>>=20
>> =C2=A0 [=C2=A0=C2=A0=C2=A0=C2=A00.000000] Linux version 4.11.0-gcc5-g13e=
0988 (kerkins@alpine1-p1)
>> (gcc version 5.2.1 20151001 (GCC) ) #1 SMP Mon May 8 05:33:22 AEST 2017
>> =C2=A0 [=C2=A0=C2=A0=C2=A0=C2=A00.000000] Using CoreNet Generic machine =
description
>> =C2=A0 ...
>> =C2=A0 [=C2=A0=C2=A0=C2=A0=C2=A03.216940] systemd[1]: Detected architect=
ure ppc64.
>> =C2=A0 ...
>> =C2=A0 Debian GNU/Linux stretch/sid p5020ds ttyS0
>> =C2=A0=C2=A0
>> =C2=A0 p5020ds login:
>>=20
>>=20
>> Anyway patch looks good, I'll pull it in with the rest of your tree.
>
> Are you using a 64-bit userspace?
Ah of course. It's debian so it's mostly 32-bit. I'd forgotten 32-bit
userspace was a thing! :)
I'll fix my tests to run some 64-bit binaries.
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-05-09 21:13 UTC | newest]
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2017-05-05 6:31 [PATCH] powerpc/64e: Don't place the stack beyond TASK_SIZE Scott Wood
2017-05-08 14:09 ` Michael Ellerman
2017-05-08 15:52 ` Scott Wood
2017-05-09 21:13 ` Michael Ellerman
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