Merge tag 'xfs-5.8-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fix from Darrick Wong:
 "Fix a use-after-free bug when the fs shuts down"

* tag 'xfs-5.8-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix use-after-free on CIL context on shutdown

Author: torvalds

fs/xfs/xfs_log_cil.c

@@ -671,7 +671,8 @@ xlog_cil_push_work(
 	/*
 	 * Wake up any background push waiters now this context is being pushed.
 	 */
-	wake_up_all(&ctx->push_wait);
+	if (ctx->space_used >= XLOG_CIL_BLOCKING_SPACE_LIMIT(log))
+		wake_up_all(&cil->xc_push_wait);
 
 	/*
 	 * Check if we've anything to push. If there is nothing, then we don't
@@ -743,13 +744,12 @@ xlog_cil_push_work(
 
 	/*
 	 * initialise the new context and attach it to the CIL. Then attach
-	 * the current context to the CIL committing lsit so it can be found
+	 * the current context to the CIL committing list so it can be found
 	 * during log forces to extract the commit lsn of the sequence that
 	 * needs to be forced.
 	 */
 	INIT_LIST_HEAD(&new_ctx->committing);
 	INIT_LIST_HEAD(&new_ctx->busy_extents);
-	init_waitqueue_head(&new_ctx->push_wait);
 	new_ctx->sequence = ctx->sequence + 1;
 	new_ctx->cil = cil;
 	cil->xc_ctx = new_ctx;
@@ -937,7 +937,7 @@ xlog_cil_push_background(
 	if (cil->xc_ctx->space_used >= XLOG_CIL_BLOCKING_SPACE_LIMIT(log)) {
 		trace_xfs_log_cil_wait(log, cil->xc_ctx->ticket);
 		ASSERT(cil->xc_ctx->space_used < log->l_logsize);
-		xlog_wait(&cil->xc_ctx->push_wait, &cil->xc_push_lock);
+		xlog_wait(&cil->xc_push_wait, &cil->xc_push_lock);
 		return;
 	}
 
@@ -1216,12 +1216,12 @@ xlog_cil_init(
 	INIT_LIST_HEAD(&cil->xc_committing);
 	spin_lock_init(&cil->xc_cil_lock);
 	spin_lock_init(&cil->xc_push_lock);
+	init_waitqueue_head(&cil->xc_push_wait);
 	init_rwsem(&cil->xc_ctx_lock);
 	init_waitqueue_head(&cil->xc_commit_wait);
 
 	INIT_LIST_HEAD(&ctx->committing);
 	INIT_LIST_HEAD(&ctx->busy_extents);
-	init_waitqueue_head(&ctx->push_wait);
 	ctx->sequence = 1;
 	ctx->cil = cil;
 	cil->xc_ctx = ctx;

fs/xfs/xfs_log_priv.h

@@ -240,7 +240,6 @@ struct xfs_cil_ctx {
 	struct xfs_log_vec	*lv_chain;	/* logvecs being pushed */
 	struct list_head	iclog_entry;
 	struct list_head	committing;	/* ctx committing list */
-	wait_queue_head_t	push_wait;	/* background push throttle */
 	struct work_struct	discard_endio_work;
 };
 
@@ -274,6 +273,7 @@ struct xfs_cil {
 	wait_queue_head_t	xc_commit_wait;
 	xfs_lsn_t		xc_current_sequence;
 	struct work_struct	xc_push_work;
+	wait_queue_head_t	xc_push_wait;	/* background push throttle */
 } ____cacheline_aligned_in_smp;
 
 /*