diff options
| -rw-r--r-- | include/linux/unwind_deferred.h | 18 | ||||
| -rw-r--r-- | kernel/unwind/deferred.c | 5 |
2 files changed, 13 insertions, 10 deletions
diff --git a/include/linux/unwind_deferred.h b/include/linux/unwind_deferred.h index b9ec4c8515c7..2efbda01e959 100644 --- a/include/linux/unwind_deferred.h +++ b/include/linux/unwind_deferred.h @@ -20,10 +20,14 @@ struct unwind_work { enum { UNWIND_PENDING_BIT = 0, + UNWIND_USED_BIT, }; enum { UNWIND_PENDING = BIT(UNWIND_PENDING_BIT), + + /* Set if the unwinding was used (directly or deferred) */ + UNWIND_USED = BIT(UNWIND_USED_BIT) }; void unwind_task_init(struct task_struct *task); @@ -49,15 +53,11 @@ static __always_inline void unwind_reset_info(void) return; } while (!try_cmpxchg(&info->unwind_mask, &bits, 0UL)); current->unwind_info.id.id = 0; - } - /* - * As unwind_user_faultable() can be called directly and - * depends on nr_entries being cleared on exit to user, - * this needs to be a separate conditional. - */ - if (unlikely(info->cache)) { - info->cache->nr_entries = 0; - info->cache->unwind_completed = 0; + + if (unlikely(info->cache)) { + info->cache->nr_entries = 0; + info->cache->unwind_completed = 0; + } } } diff --git a/kernel/unwind/deferred.c b/kernel/unwind/deferred.c index a3d26014a2e6..2311b725d691 100644 --- a/kernel/unwind/deferred.c +++ b/kernel/unwind/deferred.c @@ -45,7 +45,7 @@ static inline bool try_assign_cnt(struct unwind_task_info *info, u32 cnt) static DEFINE_MUTEX(callback_mutex); static LIST_HEAD(callbacks); -#define RESERVED_BITS (UNWIND_PENDING) +#define RESERVED_BITS (UNWIND_PENDING | UNWIND_USED) /* Zero'd bits are available for assigning callback users */ static unsigned long unwind_mask = RESERVED_BITS; @@ -140,6 +140,9 @@ int unwind_user_faultable(struct unwind_stacktrace *trace) cache->nr_entries = trace->nr; + /* Clear nr_entries on way back to user space */ + set_bit(UNWIND_USED_BIT, &info->unwind_mask); + return 0; } |