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Date:      Mon, 8 May 2017 22:24:07 +0000 (UTC)
From:      Alexander Motin <mav@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org
Subject:   svn commit: r317988 - stable/11/sys/cam/ctl
Message-ID:  <201705082224.v48MO7xJ085401@repo.freebsd.org>
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Author: mav
Date: Mon May  8 22:24:06 2017
New Revision: 317988
URL: https://svnweb.freebsd.org/changeset/base/317988

Log:
  MFC r317370: Change ctl_free_lun() locking.
  
  This fixes potential callout_drain() sleep under non-sleepable lock.
  
  PR:		218167

Modified:
  stable/11/sys/cam/ctl/ctl.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/cam/ctl/ctl.c
==============================================================================
--- stable/11/sys/cam/ctl/ctl.c	Mon May  8 22:23:01 2017	(r317987)
+++ stable/11/sys/cam/ctl/ctl.c	Mon May  8 22:24:06 2017	(r317988)
@@ -4731,18 +4731,20 @@ ctl_free_lun(struct ctl_lun *lun)
 	struct ctl_lun *nlun;
 	int i;
 
-	mtx_assert(&softc->ctl_lock, MA_OWNED);
+	KASSERT(TAILQ_EMPTY(&lun->ooa_queue),
+	    ("Freeing a LUN %p with outstanding I/O!\n", lun));
 
+	mtx_lock(&softc->ctl_lock);
 	STAILQ_REMOVE(&softc->lun_list, lun, ctl_lun, links);
-
 	ctl_clear_mask(softc->ctl_lun_mask, lun->lun);
-
 	softc->ctl_luns[lun->lun] = NULL;
-
-	if (!TAILQ_EMPTY(&lun->ooa_queue))
-		panic("Freeing a LUN %p with outstanding I/O!!\n", lun);
-
 	softc->num_luns--;
+	STAILQ_FOREACH(nlun, &softc->lun_list, links) {
+		mtx_lock(&nlun->lun_lock);
+		ctl_est_ua_all(nlun, -1, CTL_UA_LUN_CHANGE);
+		mtx_unlock(&nlun->lun_lock);
+	}
+	mtx_unlock(&softc->ctl_lock);
 
 	/*
 	 * Tell the backend to free resources, if this LUN has a backend.
@@ -4752,7 +4754,6 @@ ctl_free_lun(struct ctl_lun *lun)
 
 	lun->ie_reportcnt = UINT32_MAX;
 	callout_drain(&lun->ie_callout);
-
 	ctl_tpc_lun_shutdown(lun);
 	mtx_destroy(&lun->lun_lock);
 	free(lun->lun_devid, M_CTL);
@@ -4765,12 +4766,6 @@ ctl_free_lun(struct ctl_lun *lun)
 	if (lun->flags & CTL_LUN_MALLOCED)
 		free(lun, M_CTL);
 
-	STAILQ_FOREACH(nlun, &softc->lun_list, links) {
-		mtx_lock(&nlun->lun_lock);
-		ctl_est_ua_all(nlun, -1, CTL_UA_LUN_CHANGE);
-		mtx_unlock(&nlun->lun_lock);
-	}
-
 	return (0);
 }
 
@@ -5027,9 +5022,7 @@ ctl_invalidate_lun(struct ctl_be_lun *be
 	 */
 	if (TAILQ_EMPTY(&lun->ooa_queue)) {
 		mtx_unlock(&lun->lun_lock);
-		mtx_lock(&softc->ctl_lock);
 		ctl_free_lun(lun);
-		mtx_unlock(&softc->ctl_lock);
 	} else
 		mtx_unlock(&lun->lun_lock);
 
@@ -13068,9 +13061,7 @@ ctl_process_done(union ctl_io *io)
 	if ((lun->flags & CTL_LUN_INVALID)
 	 && TAILQ_EMPTY(&lun->ooa_queue)) {
 		mtx_unlock(&lun->lun_lock);
-		mtx_lock(&softc->ctl_lock);
 		ctl_free_lun(lun);
-		mtx_unlock(&softc->ctl_lock);
 	} else
 		mtx_unlock(&lun->lun_lock);

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