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- Do the delayed RCU wakeup for kthreads in the proper order so that

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former doesn't get ignored
 
 - A noinstr warning fix
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Merge tag 'core_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core fixes from Borislav Petkov:

 - Do the delayed RCU wakeup for kthreads in the proper order so that
   former doesn't get ignored

 - A noinstr warning fix

* tag 'core_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up
  entry: Fix noinstr warning in __enter_from_user_mode()
This commit is contained in:
Linus Torvalds 2023-03-26 09:06:20 -07:00
commit f6cdaeb08b
3 changed files with 6 additions and 2 deletions
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1
include/linux/context_tracking.h
View File

@ -96,6 +96,7 @@ static inline void user_exit_irqoff(void) { }
static inline int exception_enter(void) { return 0; }
static inline void exception_exit(enum ctx_state prev_ctx) { }
static inline int ct_state(void) { return -1; }
static inline int __ct_state(void) { return -1; }
static __always_inline bool context_tracking_guest_enter(void) { return false; }
static inline void context_tracking_guest_exit(void) { }
#define CT_WARN_ON(cond) do { } while (0)

2
include/linux/context_tracking_state.h
View File

@ -46,7 +46,9 @@ struct context_tracking {
#ifdef CONFIG_CONTEXT_TRACKING
DECLARE_PER_CPU(struct context_tracking, context_tracking);
#endif
#ifdef CONFIG_CONTEXT_TRACKING_USER
static __always_inline int __ct_state(void)
{
return arch_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_STATE_MASK;

5
kernel/entry/common.c
View File

@ -21,7 +21,7 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
arch_enter_from_user_mode(regs);
lockdep_hardirqs_off(CALLER_ADDR0);
CT_WARN_ON(ct_state() != CONTEXT_USER);
CT_WARN_ON(__ct_state() != CONTEXT_USER);
user_exit_irqoff();
instrumentation_begin();
@ -192,13 +192,14 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
static void exit_to_user_mode_prepare(struct pt_regs *regs)
{
unsigned long ti_work = read_thread_flags();
unsigned long ti_work;
lockdep_assert_irqs_disabled();
/* Flush pending rcuog wakeup before the last need_resched() check */
tick_nohz_user_enter_prepare();
ti_work = read_thread_flags();
if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
ti_work = exit_to_user_mode_loop(regs, ti_work);