diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/timekeeping.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 97db2e9393f9..c4230f44e1ea 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -858,7 +858,11 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act * the downside that the reader side does not longer benefit from * the cacheline optimized data layout of the timekeeper and requires * another indirection. + * + * Write xtime_sec first so that even if the memcpy() tears the store + * data integrity is provided for ktime_get_real_seconds(). */ + WRITE_ONCE(tkd->timekeeper.xtime_sec, tk->xtime_sec); memcpy(&tkd->timekeeper, tk, sizeof(*tk)); write_seqcount_end(&tkd->seq); } @@ -1186,11 +1190,11 @@ time64_t ktime_get_real_seconds(void) unsigned int seq; if (IS_ENABLED(CONFIG_64BIT)) - return tk->xtime_sec; + return READ_ONCE(tk->xtime_sec); do { seq = read_seqcount_begin(&tk_core.seq); - seconds = tk->xtime_sec; + seconds = READ_ONCE(tk->xtime_sec); } while (read_seqcount_retry(&tk_core.seq, seq)); @@ -1212,7 +1216,7 @@ noinstr time64_t __ktime_get_real_seconds(void) { struct timekeeper *tk = &tk_core.timekeeper; - return tk->xtime_sec; + return READ_ONCE(tk->xtime_sec); } static inline u64 tk_clock_read_snapshot(const struct tk_read_base *tkr, |