diff options
Diffstat (limited to 'arch/x86/kernel/traps.c')
| -rw-r--r-- | arch/x86/kernel/traps.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 7176f84f95a4..c74f2f5652da 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -110,15 +110,11 @@ static inline void preempt_conditional_cli(struct pt_regs *regs) enum ctx_state ist_enter(struct pt_regs *regs) { - /* - * We are atomic because we're on the IST stack (or we're on x86_32, - * in which case we still shouldn't schedule. - */ - preempt_count_add(HARDIRQ_OFFSET); + enum ctx_state prev_state; if (user_mode_vm(regs)) { /* Other than that, we're just an exception. */ - return exception_enter(); + prev_state = exception_enter(); } else { /* * We might have interrupted pretty much anything. In @@ -127,12 +123,27 @@ enum ctx_state ist_enter(struct pt_regs *regs) * but we need to notify RCU. */ rcu_nmi_enter(); - return IN_KERNEL; /* the value is irrelevant. */ + prev_state = IN_KERNEL; /* the value is irrelevant. */ } + + /* + * We are atomic because we're on the IST stack (or we're on x86_32, + * in which case we still shouldn't schedule). + * + * This must be after exception_enter(), because exception_enter() + * won't do anything if in_interrupt() returns true. + */ + preempt_count_add(HARDIRQ_OFFSET); + + /* This code is a bit fragile. Test it. */ + rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work"); + + return prev_state; } void ist_exit(struct pt_regs *regs, enum ctx_state prev_state) { + /* Must be before exception_exit. */ preempt_count_sub(HARDIRQ_OFFSET); if (user_mode_vm(regs)) |