Merge tag 'mm-hotfixes-stable-2024-05-25-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "16 hotfixes, 11 of which are cc:stable.

  A few nilfs2 fixes, the remainder are for MM: a couple of selftests
  fixes, various singletons fixing various issues in various parts"

* tag 'mm-hotfixes-stable-2024-05-25-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/ksm: fix possible UAF of stable_node
  mm/memory-failure: fix handling of dissolved but not taken off from buddy pages
  mm: /proc/pid/smaps_rollup: avoid skipping vma after getting mmap_lock again
  nilfs2: fix potential hang in nilfs_detach_log_writer()
  nilfs2: fix unexpected freezing of nilfs_segctor_sync()
  nilfs2: fix use-after-free of timer for log writer thread
  selftests/mm: fix build warnings on ppc64
  arm64: patching: fix handling of execmem addresses
  selftests/mm: compaction_test: fix bogus test success and reduce probability of OOM-killer invocation
  selftests/mm: compaction_test: fix incorrect write of zero to nr_hugepages
  selftests/mm: compaction_test: fix bogus test success on Aarch64
  mailmap: update email address for Satya Priya
  mm/huge_memory: don't unpoison huge_zero_folio
  kasan, fortify: properly rename memintrinsics
  lib: add version into /proc/allocinfo output
  mm/vmalloc: fix vmalloc which may return null if called with __GFP_NOFAIL

2 files changed, 57 insertions, 15 deletions

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 6be7dd423fbd..60d4f59f7665 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2118,8 +2118,10 @@ static void nilfs_segctor_start_timer(struct nilfs_sc_info *sci)
 {
 	spin_lock(&sci->sc_state_lock);
 	if (!(sci->sc_state & NILFS_SEGCTOR_COMMIT)) {
-		sci->sc_timer.expires = jiffies + sci->sc_interval;
-		add_timer(&sci->sc_timer);
+		if (sci->sc_task) {
+			sci->sc_timer.expires = jiffies + sci->sc_interval;
+			add_timer(&sci->sc_timer);
+		}
 		sci->sc_state |= NILFS_SEGCTOR_COMMIT;
 	}
 	spin_unlock(&sci->sc_state_lock);
@@ -2166,19 +2168,36 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 	struct nilfs_segctor_wait_request wait_req;
 	int err = 0;
 
-	spin_lock(&sci->sc_state_lock);
 	init_wait(&wait_req.wq);
 	wait_req.err = 0;
 	atomic_set(&wait_req.done, 0);
+	init_waitqueue_entry(&wait_req.wq, current);
+
+	/*
+	 * To prevent a race issue where completion notifications from the
+	 * log writer thread are missed, increment the request sequence count
+	 * "sc_seq_request" and insert a wait queue entry using the current
+	 * sequence number into the "sc_wait_request" queue at the same time
+	 * within the lock section of "sc_state_lock".
+	 */
+	spin_lock(&sci->sc_state_lock);
 	wait_req.seq = ++sci->sc_seq_request;
+	add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
 	spin_unlock(&sci->sc_state_lock);
 
-	init_waitqueue_entry(&wait_req.wq, current);
-	add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
-	set_current_state(TASK_INTERRUPTIBLE);
 	wake_up(&sci->sc_wait_daemon);
 
 	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		/*
+		 * Synchronize only while the log writer thread is alive.
+		 * Leave flushing out after the log writer thread exits to
+		 * the cleanup work in nilfs_segctor_destroy().
+		 */
+		if (!sci->sc_task)
+			break;
+
 		if (atomic_read(&wait_req.done)) {
 			err = wait_req.err;
 			break;
@@ -2194,7 +2213,7 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 	return err;
 }
 
-static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
+static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err, bool force)
 {
 	struct nilfs_segctor_wait_request *wrq, *n;
 	unsigned long flags;
@@ -2202,7 +2221,7 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
 	spin_lock_irqsave(&sci->sc_wait_request.lock, flags);
 	list_for_each_entry_safe(wrq, n, &sci->sc_wait_request.head, wq.entry) {
 		if (!atomic_read(&wrq->done) &&
-		    nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq)) {
+		    (force || nilfs_cnt32_ge(sci->sc_seq_done, wrq->seq))) {
 			wrq->err = err;
 			atomic_set(&wrq->done, 1);
 		}
@@ -2320,10 +2339,21 @@ int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
  */
 static void nilfs_segctor_accept(struct nilfs_sc_info *sci)
 {
+	bool thread_is_alive;
+
 	spin_lock(&sci->sc_state_lock);
 	sci->sc_seq_accepted = sci->sc_seq_request;
+	thread_is_alive = (bool)sci->sc_task;
 	spin_unlock(&sci->sc_state_lock);
-	del_timer_sync(&sci->sc_timer);
+
+	/*
+	 * This function does not race with the log writer thread's
+	 * termination.  Therefore, deleting sc_timer, which should not be
+	 * done after the log writer thread exits, can be done safely outside
+	 * the area protected by sc_state_lock.
+	 */
+	if (thread_is_alive)
+		del_timer_sync(&sci->sc_timer);
 }
 
 /**
@@ -2340,7 +2370,7 @@ static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
 	if (mode == SC_LSEG_SR) {
 		sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
 		sci->sc_seq_done = sci->sc_seq_accepted;
-		nilfs_segctor_wakeup(sci, err);
+		nilfs_segctor_wakeup(sci, err, false);
 		sci->sc_flush_request = 0;
 	} else {
 		if (mode == SC_FLUSH_FILE)
@@ -2349,7 +2379,7 @@ static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
 			sci->sc_flush_request &= ~FLUSH_DAT_BIT;
 
 		/* re-enable timer if checkpoint creation was not done */
-		if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
+		if ((sci->sc_state & NILFS_SEGCTOR_COMMIT) && sci->sc_task &&
 		    time_before(jiffies, sci->sc_timer.expires))
 			add_timer(&sci->sc_timer);
 	}
@@ -2539,6 +2569,7 @@ static int nilfs_segctor_thread(void *arg)
 	int timeout = 0;
 
 	sci->sc_timer_task = current;
+	timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
 
 	/* start sync. */
 	sci->sc_task = current;
@@ -2606,6 +2637,7 @@ static int nilfs_segctor_thread(void *arg)
  end_thread:
 	/* end sync. */
 	sci->sc_task = NULL;
+	timer_shutdown_sync(&sci->sc_timer);
 	wake_up(&sci->sc_wait_task); /* for nilfs_segctor_kill_thread() */
 	spin_unlock(&sci->sc_state_lock);
 	return 0;
@@ -2669,7 +2701,6 @@ static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
 	INIT_LIST_HEAD(&sci->sc_gc_inodes);
 	INIT_LIST_HEAD(&sci->sc_iput_queue);
 	INIT_WORK(&sci->sc_iput_work, nilfs_iput_work_func);
-	timer_setup(&sci->sc_timer, nilfs_construction_timeout, 0);
 
 	sci->sc_interval = HZ * NILFS_SC_DEFAULT_TIMEOUT;
 	sci->sc_mjcp_freq = HZ * NILFS_SC_DEFAULT_SR_FREQ;
@@ -2723,6 +2754,13 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 		|| sci->sc_seq_request != sci->sc_seq_done);
 	spin_unlock(&sci->sc_state_lock);
 
+	/*
+	 * Forcibly wake up tasks waiting in nilfs_segctor_sync(), which can
+	 * be called from delayed iput() via nilfs_evict_inode() and can race
+	 * with the above log writer thread termination.
+	 */
+	nilfs_segctor_wakeup(sci, 0, true);
+
 	if (flush_work(&sci->sc_iput_work))
 		flag = true;
 
@@ -2748,7 +2786,6 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 
 	down_write(&nilfs->ns_segctor_sem);
 
-	timer_shutdown_sync(&sci->sc_timer);
 	kfree(sci);
 }
 
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e5a5f015ff03..f8d35f993fe5 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -970,12 +970,17 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 				break;
 
 			/* Case 1 and 2 above */
-			if (vma->vm_start >= last_vma_end)
+			if (vma->vm_start >= last_vma_end) {
+				smap_gather_stats(vma, &mss, 0);
+				last_vma_end = vma->vm_end;
 				continue;
+			}
 
 			/* Case 4 above */
-			if (vma->vm_end > last_vma_end)
+			if (vma->vm_end > last_vma_end) {
 				smap_gather_stats(vma, &mss, last_vma_end);
+				last_vma_end = vma->vm_end;
+			}
 		}
 	} for_each_vma(vmi, vma);