From: Andy Lutomirski <[email protected]>
commit 22cd978e598618e82c3c3348d2069184f6884182 upstream.
Commit:
8bb2610bc496 ("x86/entry/64/compat: Preserve r8-r11 in int $0x80")
was busted: my original patch had a minor conflict with
some of the nospec changes, but "git apply" is very clever
and silently accepted the patch by making the same changes
to a different function in the same file. There was obviously
a huge offset, but "git apply" for some reason doesn't feel
any need to say so.
Move the changes to the correct function. Now the
test_syscall_vdso_32 selftests passes.
If anyone cares to observe the original problem, try applying the
patch at:
https://lore.kernel.org/lkml/d4c4d9985fbe64f8c9e19291886453914b48caee.1523975710.git.l...@kernel.org/raw
to the kernel at 316d097c4cd4e7f2ef50c40cff2db266593c4ec4:
- "git am" and "git apply" accept the patch without any complaints at all
- "patch -p1" at least prints out a message about the huge offset.
Reported-by: [email protected]
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected] #v4.17+
Fixes: 8bb2610bc496 ("x86/entry/64/compat: Preserve r8-r11 in int $0x80")
Link:
http://lkml.kernel.org/r/6012b922485401bc42676e804171ded262fc2ef2.1530078306.git.l...@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Alistair Delva <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64_compat.S | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -84,13 +84,13 @@ ENTRY(entry_SYSENTER_compat)
pushq %rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
- pushq %r8 /* pt_regs->r8 */
+ pushq $0 /* pt_regs->r8 = 0 */
xorl %r8d, %r8d /* nospec r8 */
- pushq %r9 /* pt_regs->r9 */
+ pushq $0 /* pt_regs->r9 = 0 */
xorl %r9d, %r9d /* nospec r9 */
- pushq %r10 /* pt_regs->r10 */
+ pushq $0 /* pt_regs->r10 = 0 */
xorl %r10d, %r10d /* nospec r10 */
- pushq %r11 /* pt_regs->r11 */
+ pushq $0 /* pt_regs->r11 = 0 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
@@ -357,13 +357,13 @@ ENTRY(entry_INT80_compat)
pushq %rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
- pushq $0 /* pt_regs->r8 = 0 */
+ pushq %r8 /* pt_regs->r8 */
xorl %r8d, %r8d /* nospec r8 */
- pushq $0 /* pt_regs->r9 = 0 */
+ pushq %r9 /* pt_regs->r9 */
xorl %r9d, %r9d /* nospec r9 */
- pushq $0 /* pt_regs->r10 = 0 */
+ pushq %r10 /* pt_regs->r10*/
xorl %r10d, %r10d /* nospec r10 */
- pushq $0 /* pt_regs->r11 = 0 */
+ pushq %r11 /* pt_regs->r11 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
