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authorH. Peter Anvin <hpa@linux.intel.com>2014-04-30 14:03:25 -0700
committerBen Hutchings <ben@decadent.org.uk>2014-08-06 18:07:41 +0100
commit6806fa8b6795aba9be8742a8f598f60eed26f875 (patch)
tree92b6f89402f55a22178b447beafdb152c94324f5 /arch/x86
parent1280d20457d89a4254842592dc5d53af30055a20 (diff)
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x86-32, espfix: Remove filter for espfix32 due to race
commit 246f2d2ee1d715e1077fc47d61c394569c8ee692 upstream. It is not safe to use LAR to filter when to go down the espfix path, because the LDT is per-process (rather than per-thread) and another thread might change the descriptors behind our back. Fortunately it is always *safe* (if a bit slow) to go down the espfix path, and a 32-bit LDT stack segment is extremely rare. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/entry_32.S5
1 files changed, 0 insertions, 5 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index db090f6..d2284c4 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -553,11 +553,6 @@ ENTRY(iret_exc)
CFI_RESTORE_STATE
ldt_ss:
- larl PT_OLDSS(%esp), %eax
- jnz restore_nocheck
- testl $0x00400000, %eax # returning to 32bit stack?
- jnz restore_nocheck # allright, normal return
-
#ifdef CONFIG_PARAVIRT
/*
* The kernel can't run on a non-flat stack if paravirt mode