diff options
| -rw-r--r-- | include/linux/context_tracking_state.h | 1 | ||||
| -rw-r--r-- | kernel/context_tracking.c | 29 |
2 files changed, 30 insertions, 0 deletions
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 6b7b96a32b75..678ecdf90cf6 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -12,6 +12,7 @@ struct context_tracking { * may be further optimized using static keys. */ bool active; + int recursion; enum ctx_state { CONTEXT_KERNEL = 0, CONTEXT_USER, diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 72d59a1a6eb6..5b11a10e196a 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -38,6 +38,25 @@ void context_tracking_cpu_set(int cpu) } } +static bool context_tracking_recursion_enter(void) +{ + int recursion; + + recursion = __this_cpu_inc_return(context_tracking.recursion); + if (recursion == 1) + return true; + + WARN_ONCE((recursion < 1), "Invalid context tracking recursion value %d\n", recursion); + __this_cpu_dec(context_tracking.recursion); + + return false; +} + +static void context_tracking_recursion_exit(void) +{ + __this_cpu_dec(context_tracking.recursion); +} + /** * context_tracking_enter - Inform the context tracking that the CPU is going * enter user or guest space mode. @@ -75,6 +94,9 @@ void context_tracking_enter(enum ctx_state state) WARN_ON_ONCE(!current->mm); local_irq_save(flags); + if (!context_tracking_recursion_enter()) + goto out_irq_restore; + if ( __this_cpu_read(context_tracking.state) != state) { if (__this_cpu_read(context_tracking.active)) { /* @@ -105,6 +127,8 @@ void context_tracking_enter(enum ctx_state state) */ __this_cpu_write(context_tracking.state, state); } + context_tracking_recursion_exit(); +out_irq_restore: local_irq_restore(flags); } NOKPROBE_SYMBOL(context_tracking_enter); @@ -139,6 +163,9 @@ void context_tracking_exit(enum ctx_state state) return; local_irq_save(flags); + if (!context_tracking_recursion_enter()) + goto out_irq_restore; + if (__this_cpu_read(context_tracking.state) == state) { if (__this_cpu_read(context_tracking.active)) { /* @@ -153,6 +180,8 @@ void context_tracking_exit(enum ctx_state state) } __this_cpu_write(context_tracking.state, CONTEXT_KERNEL); } + context_tracking_recursion_exit(); +out_irq_restore: local_irq_restore(flags); } NOKPROBE_SYMBOL(context_tracking_exit); |