| Message ID | 20170505063145.21631-1-oss@buserror.net (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
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
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
Scott Wood <oss@buserror.net> writes: > 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? 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
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() ? \
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(+)