On Wed, 28 Oct, at 01:41:51PM, kernel test robot wrote:
> FYI, we noticed the below changes on
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> commit f5f3497cad8c8416a74b9aaceb127908755d020a ("x86/setup: Extend low identity map to cover whole kernel range")
>
>
> +------------------------------------------------+------------+------------+
> | | 8a53554e12 | f5f3497cad |
> +------------------------------------------------+------------+------------+
> | boot_successes | 19 | 10 |
> | boot_failures | 2 | 9 |
> | IP-Config:Auto-configuration_of_network_failed | 2 | 2 |
> | BUG:kernel_boot_crashed | 0 | 7 |
> +------------------------------------------------+------------+------------+
>
>
> [ 0.053410] smpboot: CPU0: GenuineIntel GenuineIntel QEMU Virtual CPU version 2.4.0QEMU Virtual CPU version 2.4.0 (family: 0x6, model: 0x6 (family: 0x6, model: 0x6, stepping: 0x3)
> , stepping: 0x3)
> [ 0.056666] Performance Events:
> [ 0.056666] Performance Events: no PMU driver, software events only.
> no PMU driver, software events only.
> [ 0.060520] CPU 1 irqstacks, hard=8a832000 soft=8a834000
> [ 0.060520] CPU 1 irqstacks, hard=8a832000 soft=8a834000
> [ 0.061605] x86: Booting SMP configuration:
> [ 0.061605] x86: Booting SMP configuration:
> [ 0.062445] .... node #0, CPUs:
> [ 0.062445] .... node #0, CPUs: #1 #1
> Elapsed time: 10
> BUG: kernel boot crashed
Yikes! Yeah, I can reproduce this. It appears the STARTUP IPI code is
triggering this crash in wakeup_secondary_cpu_via_init().
I'll take a look unless anyone else has any bright ideas?
* Matt Fleming <[email protected]> wrote:
> On Wed, 28 Oct, at 01:41:51PM, kernel test robot wrote:
> > FYI, we noticed the below changes on
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > commit f5f3497cad8c8416a74b9aaceb127908755d020a ("x86/setup: Extend low identity map to cover whole kernel range")
> >
> >
> > +------------------------------------------------+------------+------------+
> > | | 8a53554e12 | f5f3497cad |
> > +------------------------------------------------+------------+------------+
> > | boot_successes | 19 | 10 |
> > | boot_failures | 2 | 9 |
> > | IP-Config:Auto-configuration_of_network_failed | 2 | 2 |
> > | BUG:kernel_boot_crashed | 0 | 7 |
> > +------------------------------------------------+------------+------------+
> >
> >
> > [ 0.053410] smpboot: CPU0: GenuineIntel GenuineIntel QEMU Virtual CPU version 2.4.0QEMU Virtual CPU version 2.4.0 (family: 0x6, model: 0x6 (family: 0x6, model: 0x6, stepping: 0x3)
> > , stepping: 0x3)
> > [ 0.056666] Performance Events:
> > [ 0.056666] Performance Events: no PMU driver, software events only.
> > no PMU driver, software events only.
> > [ 0.060520] CPU 1 irqstacks, hard=8a832000 soft=8a834000
> > [ 0.060520] CPU 1 irqstacks, hard=8a832000 soft=8a834000
> > [ 0.061605] x86: Booting SMP configuration:
> > [ 0.061605] x86: Booting SMP configuration:
> > [ 0.062445] .... node #0, CPUs:
> > [ 0.062445] .... node #0, CPUs: #1 #1
> > Elapsed time: 10
> > BUG: kernel boot crashed
>
> Yikes! Yeah, I can reproduce this. It appears the STARTUP IPI code is
> triggering this crash in wakeup_secondary_cpu_via_init().
>
> I'll take a look unless anyone else has any bright ideas?
Unfortunately this commit is now part of the v4.3 kernel, so we need a quick
solution or a quick revert.
Thanks,
Ingo
On Tue, 03 Nov, at 09:07:34AM, Ingo Molnar wrote:
>
> Unfortunately this commit is now part of the v4.3 kernel, so we need a quick
> solution or a quick revert.
Quick solution:
---
>From ebb589d9cd83cce838d540aea1951d9b902eb0bc Mon Sep 17 00:00:00 2001
From: Matt Fleming <[email protected]>
Date: Tue, 3 Nov 2015 13:40:41 +0000
Subject: [PATCH] x86/setup: Fix recent boot crash on 32-bit SMP machines
The LKP test robot reported that the bug fix in commit f5f3497cad8c
("x86/setup: Extend low identity map to cover whole kernel range")
causes CONFIG_X86_32 SMP machines to crash on boot when trying to
bring AP cpus online.
The above commit erroneously copies too many of the PGD entries to the
low memory region of 'identity_page_table', resulting in some of the
kernel mappings for PAGE_OFFSET being trashed because,
KERNEL_PGD_PTRS > KERNEL_PGD_BOUNDARY
The maximum number of PGD entries we can copy without corrupting the
kernel mapping is KERNEL_PGD_BOUNDARY or pgd_index(PAGE_OFFSET).
Reported-by: Ying Huang <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Laszlo Ersek <[email protected]>
Cc: <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
---
arch/x86/kernel/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a3cccbfc5f77..2b8cbd693da8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1180,7 +1180,7 @@ void __init setup_arch(char **cmdline_p)
*/
clone_pgd_range(initial_page_table,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
- KERNEL_PGD_PTRS);
+ KERNEL_PGD_BOUNDARY);
#endif
tboot_probe();
--
2.6.2
Commit-ID: 1c5dac914794f0170e1582d8ffdee52d30e0e4dd
Gitweb: http://git.kernel.org/tip/1c5dac914794f0170e1582d8ffdee52d30e0e4dd
Author: Matt Fleming <[email protected]>
AuthorDate: Tue, 3 Nov 2015 13:40:41 +0000
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 4 Nov 2015 11:48:47 +0100
x86/setup: Fix recent boot crash on 32-bit SMP machines
The LKP test robot reported that the bug fix in commit f5f3497cad8c
("x86/setup: Extend low identity map to cover whole kernel range")
causes CONFIG_X86_32 SMP machines to crash on boot when trying to
bring AP cpus online.
The above commit erroneously copies too many of the PGD entries to the
low memory region of 'identity_page_table', resulting in some of the
kernel mappings for PAGE_OFFSET being trashed because,
KERNEL_PGD_PTRS > KERNEL_PGD_BOUNDARY
The maximum number of PGD entries we can copy without corrupting the
kernel mapping is KERNEL_PGD_BOUNDARY or pgd_index(PAGE_OFFSET).
Fixes: f5f3497cad8c "x86/setup: Extend low identity map to cover whole kernel range"
Reported-by: Ying Huang <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Laszlo Ersek <[email protected]>
Cc: [email protected]
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/kernel/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a3cccbf..2b8cbd6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1180,7 +1180,7 @@ void __init setup_arch(char **cmdline_p)
*/
clone_pgd_range(initial_page_table,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
- KERNEL_PGD_PTRS);
+ KERNEL_PGD_BOUNDARY);
#endif
tboot_probe();