[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <tip-f72075c9eda8a43aeea2f9dbb8d187afd4a76f0b@git.kernel.org>
Date: Thu, 11 Aug 2016 09:19:45 -0700
From: tip-bot for Alex Thorlton <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: jpoimboe@...hat.com, brgerst@...il.com, travis@....com,
luto@...nel.org, tglx@...utronix.de, peterz@...radead.org,
dvlasenk@...hat.com, bp@...en8.de, ard.biesheuvel@...aro.org,
mingo@...nel.org, linux-kernel@...r.kernel.org, hpa@...or.com,
rja@....com, bp@...e.de, torvalds@...ux-foundation.org,
athorlton@....com, matt@...eblueprint.co.uk
Subject: [tip:efi/urgent] x86/platform/uv: Skip UV runtime services mapping
in the efi_runtime_disabled case
Commit-ID: f72075c9eda8a43aeea2f9dbb8d187afd4a76f0b
Gitweb: http://git.kernel.org/tip/f72075c9eda8a43aeea2f9dbb8d187afd4a76f0b
Author: Alex Thorlton <athorlton@....com>
AuthorDate: Thu, 11 Aug 2016 11:41:59 +0100
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 11 Aug 2016 13:55:36 +0200
x86/platform/uv: Skip UV runtime services mapping in the efi_runtime_disabled case
This problem has actually been in the UV code for a while, but we didn't
catch it until recently, because we had been relying on EFI_OLD_MEMMAP
to allow our systems to boot for a period of time. We noticed the issue
when trying to kexec a recent community kernel, where we hit this NULL
pointer dereference in efi_sync_low_kernel_mappings():
[ 0.337515] BUG: unable to handle kernel NULL pointer dereference at 0000000000000880
[ 0.346276] IP: [<ffffffff8105df8d>] efi_sync_low_kernel_mappings+0x5d/0x1b0
The problem doesn't show up with EFI_OLD_MEMMAP because we skip the
chunk of setup_efi_state() that sets the efi_loader_signature for the
kexec'd kernel. When the kexec'd kernel boots, it won't set EFI_BOOT in
setup_arch, so we completely avoid the bug.
We always kexec with noefi on the command line, so this shouldn't be an
issue, but since we're not actually checking for efi_runtime_disabled in
uv_bios_init(), we end up trying to do EFI runtime callbacks when we
shouldn't be. This patch just adds a check for efi_runtime_disabled in
uv_bios_init() so that we don't map in uv_systab when runtime_disabled ==
true.
Signed-off-by: Alex Thorlton <athorlton@....com>
Signed-off-by: Matt Fleming <matt@...eblueprint.co.uk>
Cc: <stable@...r.kernel.org> # v4.7
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Borislav Petkov <bp@...e.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mike Travis <travis@....com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Russ Anderson <rja@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-efi@...r.kernel.org
Link: http://lkml.kernel.org/r/1470912120-22831-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
arch/x86/platform/uv/bios_uv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index 66b2166..0df8a03 100644
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -187,7 +187,8 @@ EXPORT_SYMBOL_GPL(uv_bios_set_legacy_vga_target);
void uv_bios_init(void)
{
uv_systab = NULL;
- if ((efi.uv_systab == EFI_INVALID_TABLE_ADDR) || !efi.uv_systab) {
+ if ((efi.uv_systab == EFI_INVALID_TABLE_ADDR) ||
+ !efi.uv_systab || efi_runtime_disabled()) {
pr_crit("UV: UVsystab: missing\n");
return;
}
Powered by blists - more mailing lists