From: Andy Lutomirski luto@kernel.org
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.152397...
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: zhijianx.li@intel.com Signed-off-by: Andy Lutomirski luto@kernel.org Cc: Arjan van de Ven arjan@linux.intel.com Cc: Borislav Petkov bp@alien8.de Cc: Dan Williams dan.j.williams@intel.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: David Woodhouse dwmw2@infradead.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org #v4.17+ Fixes: 8bb2610bc496 ("x86/entry/64/compat: Preserve r8-r11 in int $0x80") Link: http://lkml.kernel.org/r/6012b922485401bc42676e804171ded262fc2ef2.1530078306... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Alistair Delva adelva@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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 */