ubsan, x86: Annotate and allow __ubsan_handle_shift_out_of_bounds() in uaccess regions

[mirror_ubuntu-focal-kernel.git] / mm / ksm.c

diff --git a/mm/ksm.c b/mm/ksm.c
index dbee2eb4dd05eec01379ad1480384c55bdf43449..9ea848346a0ba71407fa71a7f617f80d0816ccdf 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -885,13 +885,13 @@ static int remove_stable_node(struct stable_node *stable_node)
                return 0;
        }
 
-       if (WARN_ON_ONCE(page_mapped(page))) {
-               /*
-                * This should not happen: but if it does, just refuse to let
-                * merge_across_nodes be switched - there is no need to panic.
-                */
-               err = -EBUSY;
-       } else {
+       /*
+        * Page could be still mapped if this races with __mmput() running in
+        * between ksm_exit() and exit_mmap(). Just refuse to let
+        * merge_across_nodes/max_page_sharing be switched.
+        */
+       err = -EBUSY;
+       if (!page_mapped(page)) {
                /*
                 * The stable node did not yet appear stale to get_ksm_page(),
                 * since that allows for an unmapped ksm page to be recognized
@@ -2414,9 +2414,14 @@ static int ksm_scan_thread(void *nothing)
 
                if (ksmd_should_run()) {
                        sleep_ms = READ_ONCE(ksm_thread_sleep_millisecs);
-                       wait_event_interruptible_timeout(ksm_iter_wait,
-                               sleep_ms != READ_ONCE(ksm_thread_sleep_millisecs),
-                               msecs_to_jiffies(sleep_ms));
+                       if (sleep_ms >= 1000)
+                               wait_event_interruptible_timeout(ksm_iter_wait,
+                                       sleep_ms != READ_ONCE(ksm_thread_sleep_millisecs),
+                                       msecs_to_jiffies(round_jiffies_relative(sleep_ms)));
+                       else
+                               wait_event_interruptible_timeout(ksm_iter_wait,
+                                       sleep_ms != READ_ONCE(ksm_thread_sleep_millisecs),
+                                       msecs_to_jiffies(sleep_ms));
                } else {
                        wait_event_freezable(ksm_thread_wait,
                                ksmd_should_run() || kthread_should_stop());