From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 90F2D18D636; Fri, 4 Sep 2026 05:54:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501242; cv=none; b=AueR9JHYK6bW1yYn152/eO1nrAWCEUp8+4NxBZZW5bvI+7haE77vx+BwOQgw10HhgYQ6DZ5+GWXLRrfW9uSFn+13z3BiKdH8Ierr3PpcnstuBiuyapAYjHQFd9JTDVe6TSOUdSWTOJKikc+dO4UO36PrxAKUgy+MTyV234OtMR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501242; c=relaxed/simple; bh=PsWDz7xey5R9ZtOuyBRk99qX0k7p8u1wPepFq1Aq12E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MFX3Kfc15bpekL/pOBJYfutOXsIAlBgdDl6GfHYrrU8t09vshAiCouS+Ew5WfhHDNzxCa5JfQPHCHBV3m3MI/BhhwSLV39Hh/nvoAAucgXqkBJyH+CemN39Tibkn3o3WdbAGR1WwpiWOZ0L8OCcG3YCA16wOullsp/cOrvd2fOY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=au5RBybm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="au5RBybm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFF611F00A3D; Fri, 4 Sep 2026 05:53:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501240; bh=w/jjMH3WsWycsVZyfN0gZfRYhMbXoIafSWAgWIkZ1XM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=au5RBybmu0pT7kPfHN34XVoj7bNK+YHQ5gJBFedVzXJ8gnwiZw63bAHj1gILGxlaP Jh5TWDUGgsIO23zi4z9l64YLjqWX25c6852gEPcDP03q79Bfdgdslf1L/KNUDJiDBj NtkDXth4EInpAEx4aMKg6/niocjYGC7xhCzu26SI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joseph Qi , Changwei Ge , Heming Zhao , Joel Becker , Jun Piao , Junxiao Bi , Mark Fasheh , Andrew Morton Subject: [PATCH 6.18 339/552] ocfs2: cluster: dont sleep while holding o2hb_live_lock in o2hb_region_pin() Date: Fri, 4 Sep 2026 06:58:16 +0200 Message-ID: <20260904045757.942900962@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joseph Qi commit af09df89db9a68a1d76df0f75667998135bc8d65 upstream. Patch series "ocfs2: cluster: o2hb_region_pin() fixes", v2. This series fixes three related issues in o2hb_region_pin(), all are from the original implementation in commit: 58a3158a5d17 ("ocfs2/cluster: Pin/unpin o2hb regions"): 1) It is called with o2hb_live_lock (a spinlock) held, but the underlying configfs_depend_item() sleeps (takes inode rwsem and pins the filesystem). This triggers BUG under CONFIG_DEBUG_ATOMIC_SLEEP. 2) When called from the configfs drop_item callback, it creates a lock order inversion: parent inode_lock -> configfs root inode_lock, which can deadlock against subsystem unregistration paths taking root -> parent. 3) If pinning fails partway through o2hb_region_inc_user(), the o2hb_dependent_users counter is leaked and partially-pinned regions are never released, leaving heartbeat regions unprotected on subsequent mounts. Patch 1 reworks o2hb_region_pin() to drop o2hb_live_lock across each sleeping configfs_depend_item() call, using a config_item reference to keep the region alive while unlocked. Patch 2 adds a from_callback parameter to select configfs_depend_item_unlocked() when called from configfs context, avoiding the inode_lock nesting. Patch 3 fixes the error path in o2hb_region_inc_user() to unpin and decrement the counter on failure. This patch (of 3): o2hb_region_pin() is always called with the o2hb_live_lock spinlock held (from o2hb_region_inc_user() and o2hb_heartbeat_group_drop_item()), but it calls o2nm_depend_item() -> configfs_depend_item(), which sleeps: it pins the configfs filesystem and takes the configfs root inode rwsem. Under CONFIG_DEBUG_ATOMIC_SLEEP this triggers: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c in_atomic(): 1, ... name: mount.ocfs2 down_write configfs_depend_item o2hb_region_pin o2hb_region_inc_user o2hb_register_callback dlm_register_domain_handlers ... ocfs2_dlm_init ocfs2_mount_volume ocfs2_fill_super Rework o2hb_region_pin() to pin one region at a time with the lock dropped across the sleeping call: under o2hb_live_lock find the next eligible region and take a config_item reference to keep it alive, drop the lock, call o2nm_depend_item(), then retake the lock and record the pin. The config_item_put() is done with the lock released as well, since o2hb_region_release() also acquires o2hb_live_lock and can sleep. The region list may change while unlocked, so the scan restarts from the top after each pin. Local heartbeat still pins only the matching region; global heartbeat pins all eligible regions. The unpin path is unaffected: configfs_undepend_item() only takes a spinlock and does not sleep. Link: https://lore.kernel.org/20260722124933.430554-1-joseph.qi@linux.alibaba.com Link: https://lore.kernel.org/20260722124933.430554-2-joseph.qi@linux.alibaba.com Fixes: 58a3158a5d17 ("ocfs2/cluster: Pin/unpin o2hb regions") Signed-off-by: Joseph Qi Cc: Changwei Ge Cc: Heming Zhao Cc: Joel Becker Cc: Jun Piao Cc: Junxiao Bi Cc: Mark Fasheh Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/cluster/heartbeat.c | 126 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 101 insertions(+), 25 deletions(-) --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -43,6 +43,14 @@ static DECLARE_RWSEM(o2hb_callback_sem); * whenever any of the threads sees activity from the node in its region. */ static DEFINE_SPINLOCK(o2hb_live_lock); +/* + * Serializes region pin/unpin dependency management (o2hb_dependent_users + * and the o2nm_depend_item()/o2nm_undepend_item() calls). o2hb_region_pin() + * has to drop o2hb_live_lock across the sleeping o2nm_depend_item(), so the + * spinlock alone can no longer keep pin and unpin mutually exclusive; this + * mutex, taken outside o2hb_live_lock, does. + */ +static DEFINE_MUTEX(o2hb_dependency_mutex); static struct list_head o2hb_live_slots[O2NM_MAX_NODES]; static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)]; static LIST_HEAD(o2hb_node_events); @@ -2115,6 +2123,7 @@ static void o2hb_heartbeat_group_drop_it * If global heartbeat active and there are dependent users, * pin all regions if quorum region count <= CUT_OFF */ + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); if (!o2hb_dependent_users) @@ -2126,6 +2135,7 @@ static void o2hb_heartbeat_group_drop_it unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); } static ssize_t o2hb_heartbeat_group_dead_threshold_show(struct config_item *item, @@ -2265,46 +2275,108 @@ EXPORT_SYMBOL_GPL(o2hb_setup_callback); */ static int o2hb_region_pin(const char *region_uuid) { - int ret = 0, found = 0; - struct o2hb_region *reg; + int ret = 0, found; + struct o2hb_region *reg, *pinned; char *uuid; assert_spin_locked(&o2hb_live_lock); - list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) { - if (reg->hr_item_dropped) - continue; + do { + found = 0; + pinned = NULL; - uuid = config_item_name(®->hr_item); + list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) { + if (reg->hr_item_dropped) + continue; - /* local heartbeat */ - if (region_uuid) { - if (strcmp(region_uuid, uuid)) + uuid = config_item_name(®->hr_item); + + /* local heartbeat */ + if (region_uuid) { + if (strcmp(region_uuid, uuid)) + continue; + found = 1; + } + + if (reg->hr_item_pinned || reg->hr_item_dropped) { + if (found) + break; continue; - found = 1; + } + + /* + * Found a region that needs pinning. Take a reference + * so it stays alive while we drop the lock below. + */ + pinned = reg; + config_item_get(®->hr_item); + break; } - if (reg->hr_item_pinned || reg->hr_item_dropped) - goto skip_pin; + if (!pinned) + break; + + uuid = config_item_name(&pinned->hr_item); + + /* + * o2nm_depend_item() -> configfs_depend_item() can sleep (it + * takes the configfs root inode rwsem), so it must not run + * under o2hb_live_lock. Drop the lock across it; @pinned is + * kept alive by the reference taken above. The region list may + * change while unlocked, so we rescan from the top afterwards. + */ + spin_unlock(&o2hb_live_lock); /* Ignore ENOENT only for local hb (userdlm domain) */ - ret = o2nm_depend_item(®->hr_item); + ret = o2nm_depend_item(&pinned->hr_item); + + spin_lock(&o2hb_live_lock); if (!ret) { - mlog(ML_CLUSTER, "Pin region %s\n", uuid); - reg->hr_item_pinned = 1; - } else { - if (ret == -ENOENT && found) - ret = 0; - else { - mlog(ML_ERROR, "Pin region %s fails with %d\n", - uuid, ret); + /* + * o2hb_live_lock was dropped across o2nm_depend_item(). + * o2hb_set_quorum_device() runs in the heartbeat thread + * without o2hb_dependency_mutex, so for global heartbeat + * it may have crossed O2HB_PIN_CUT_OFF and unpinned the + * regions while we slept. If that happened this pin is + * no longer wanted; undo it and stop rather than + * resurrecting it on the rescan below. + */ + if (!region_uuid && + bitmap_weight(o2hb_quorum_region_bitmap, + O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF) { + o2nm_undepend_item(&pinned->hr_item); + spin_unlock(&o2hb_live_lock); + config_item_put(&pinned->hr_item); + spin_lock(&o2hb_live_lock); break; } + mlog(ML_CLUSTER, "Pin region %s\n", uuid); + pinned->hr_item_pinned = 1; + } else if (ret == -ENOENT && (found || !region_uuid)) { + /* + * For local hb (found): ignore ENOENT from userdlm + * domains as before. For global hb (!region_uuid): + * the region may have been detached from configfs + * while the lock was dropped — skip it and continue + * pinning the remaining regions. + */ + ret = 0; + } else { + mlog(ML_ERROR, "Pin region %s fails with %d\n", + uuid, ret); } -skip_pin: - if (found) - break; - } + + /* + * config_item_put() may drop the last reference and run + * o2hb_region_release(), which also grabs o2hb_live_lock and + * can sleep, so it must happen with the lock released. + */ + spin_unlock(&o2hb_live_lock); + config_item_put(&pinned->hr_item); + spin_lock(&o2hb_live_lock); + + /* local hb pins a single matching region */ + } while (!ret && !region_uuid); return ret; } @@ -2349,6 +2421,7 @@ static int o2hb_region_inc_user(const ch { int ret = 0; + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); /* local heartbeat */ @@ -2371,11 +2444,13 @@ static int o2hb_region_inc_user(const ch unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); return ret; } static void o2hb_region_dec_user(const char *region_uuid) { + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); /* local heartbeat */ @@ -2394,6 +2469,7 @@ static void o2hb_region_dec_user(const c unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); } int o2hb_register_callback(const char *region_uuid,