LinuxLists.cc - [PATCH] xen x86: fix early boot crash with gcc-10

2020-04-13 14:57:27

Subject: [PATCH] xen x86: fix early boot crash with gcc-10

The change fixes boot failure on VM where kernel (at least v5.4 and v5.6)
is built with gcc-10 and STACKPROTECTOR_STRONG enabled:

```
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: cpu_bringup_and_idle+0x93/0xa0
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.4.31-1.qubes.x86_64 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack+0x64/0x88
panic+0x10b/0x2ed
? cpu_bringup_and_idle+0x93/0xa0
__stack_chk_fail+0x15/0x20
cpu_bringup_and_idle+0x93/0xa
```
The change makes successfully booting the VM. The VM is hosted by
KVM hypervisor and is running Xen into.

Based on work done by Sergei Trofimovich: https://lkml.org/lkml/2020/3/26/1133

Signed-off-by: Frédéric Pierret (fepitre) <[email protected]>
---
arch/x86/xen/smp_pv.c | 2 +-
include/linux/compiler-gcc.h | 1 +
include/linux/compiler_types.h | 4 ++++
3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 8fb8a50a28b4..5c8ee4a5bb0c 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -88,7 +88,7 @@ static void cpu_bringup(void)
local_irq_enable();
}

-asmlinkage __visible void cpu_bringup_and_idle(void)
+asmlinkage __visible void __no_stack_protector cpu_bringup_and_idle(void)
{
cpu_bringup();
boot_init_stack_canary();
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index d7ee4c6bad48..fb67c743138c 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -172,3 +172,4 @@
#endif

#define __no_fgcse __attribute__((optimize("-fno-gcse")))
+#define __no_stack_protector __attribute__((optimize("-fno-stack-protector")))
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index e970f97a7fcb..069c981eddb0 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -203,6 +203,10 @@ struct ftrace_likely_data {
#define asm_inline asm
#endif

+#ifndef __no_stack_protector
+# define __no_stack_protector
+#endif
+
#ifndef __no_fgcse
# define __no_fgcse
#endif
--
2.25.1

2020-04-13 15:30:45

by Borislav Petkov

[permalink] [raw]

Subject: Re: [PATCH] xen x86: fix early boot crash with gcc-10

On Mon, Apr 13, 2020 at 02:35:35PM +0200, Frédéric Pierret (fepitre) wrote:
> The change fixes boot failure on VM where kernel (at least v5.4 and v5.6)
> is built with gcc-10 and STACKPROTECTOR_STRONG enabled:
>
> ```
> Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: cpu_bringup_and_idle+0x93/0xa0
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.4.31-1.qubes.x86_64 #1
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
> Call Trace:
> dump_stack+0x64/0x88
> panic+0x10b/0x2ed
> ? cpu_bringup_and_idle+0x93/0xa0
> __stack_chk_fail+0x15/0x20
> cpu_bringup_and_idle+0x93/0xa
> ```
> The change makes successfully booting the VM. The VM is hosted by
> KVM hypervisor and is running Xen into.
>
> Based on work done by Sergei Trofimovich: https://lkml.org/lkml/2020/3/26/1133

I was waiting for the merge window to finish to queue his patch. That is
done now, you can rebase yours ontop.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

2020-04-13 15:38:07

by Frédéric Pierret (fepitre)

[permalink] [raw]

Subject: [PATCH v2] xen x86: fix early boot crash with gcc-10

2020-04-14 13:28:39

by Borislav Petkov

[permalink] [raw]

Subject: Re: [PATCH v2] xen x86: fix early boot crash with gcc-10

On Mon, Apr 13, 2020 at 05:03:14PM +0200, Frédéric Pierret (fepitre) wrote:
> The change fixes boot failure on VM where kernel (at least v5.4 and v5.6)
> is built with gcc-10 and STACKPROTECTOR_STRONG enabled:
>
> ```
> Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: cpu_bringup_and_idle+0x93/0xa0
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.4.31-1.qubes.x86_64 #1
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
> Call Trace:
> dump_stack+0x64/0x88
> panic+0x10b/0x2ed
> ? cpu_bringup_and_idle+0x93/0xa0
> __stack_chk_fail+0x15/0x20
> cpu_bringup_and_idle+0x93/0xa
> ```
> The change makes successfully booting the VM. The VM is hosted by
> KVM hypervisor and is running Xen into.
>
> Based on work done by Sergei Trofimovich: https://lkml.org/lkml/2020/3/26/1133
>
> Signed-off-by: Frédéric Pierret (fepitre) <[email protected]>
> ---
> arch/x86/xen/smp_pv.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
> index 8fb8a50a28b4..5c8ee4a5bb0c 100644
> --- a/arch/x86/xen/smp_pv.c
> +++ b/arch/x86/xen/smp_pv.c
> @@ -88,7 +88,7 @@ static void cpu_bringup(void)
> local_irq_enable();
> }
>
> -asmlinkage __visible void cpu_bringup_and_idle(void)
> +asmlinkage __visible void __no_stack_protector cpu_bringup_and_idle(void)
> {
> cpu_bringup();
> boot_init_stack_canary();
> --

Boris O, Jürgen,

you guys might wanna wait a bit with this one:

https://lkml.kernel.org/r/[email protected]

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette