diff options
| author | H. Peter Anvin <hpa@linux.intel.com> | 2014-04-30 14:03:25 -0700 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2014-12-13 15:16:07 +0100 |
| commit | b01d7cd1de2a22665ba5d06be43d353709eb7f1f (patch) | |
| tree | 847be4e8d885512f3def65909e9d2bbd50ed1beb | |
| parent | 1d97cac8c0469759c979e9f2d48ef4122c543e3d (diff) | |
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>
(cherry picked from 3.2 commit 6806fa8b6795aba9be8742a8f598f60eed26f875)
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 8b5370c287d8..db7dbe703f0d 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -571,11 +571,6 @@ 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 |