4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Andy Lutomirski <[email protected]> commit 3383642c2f9d4f5b4fa37436db4a109a1a10018c upstream. Let's keep the stack-related logic together rather than open-coding a comparison in an assertion in the traps code. Signed-off-by: Andy Lutomirski <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/856b15bee1f55017b8f79d3758b0d51c48a08cf8.1509609304.git.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/include/asm/processor.h | 6 ++++++ arch/x86/kernel/traps.c | 3 +-- 2 files changed, 7 insertions(+), 2 deletions(-) --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -542,6 +542,12 @@ static inline unsigned long current_top_ #endif } +static inline bool on_thread_stack(void) +{ + return (unsigned long)(current_top_of_stack() - + current_stack_pointer) < THREAD_SIZE; +} + #ifdef CONFIG_PARAVIRT #include <asm/paravirt.h> #else --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -141,8 +141,7 @@ void ist_begin_non_atomic(struct pt_regs * will catch asm bugs and any attempt to use ist_preempt_enable * from double_fault. */ - BUG_ON((unsigned long)(current_top_of_stack() - - current_stack_pointer) >= THREAD_SIZE); + BUG_ON(!on_thread_stack()); preempt_enable_no_resched(); }
