diff options
| author |   H. Peter Anvin <hpa@linux.intel.com> | 2014-04-30 14:03:25 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-04-30 14:14:49 -0700 |
| commit | 246f2d2ee1d715e1077fc47d61c394569c8ee692 (patch) | |
| tree | 165efb7fc0e3427593bd33c11068b2b216ac2f43 /arch/x86/kernel/entry_32.S | |
| parent | x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack (diff) | |
| download | linux-dev-246f2d2ee1d715e1077fc47d61c394569c8ee692.tar.xz linux-dev-246f2d2ee1d715e1077fc47d61c394569c8ee692.zip | |
x86-32, espfix: Remove filter for espfix32 due to race
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
Cc: <stable@vger.kernel.org> # consider after upstream merge
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
| -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 a2a4f4697889..2780b8f3b96c 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -551,11 +551,6 @@ 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 |