From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,stable@vger.kernel.org,piaojun@huawei.com,mark@fasheh.com,junxiao.bi@oracle.com,jlbec@evilplan.org,heming.zhao@suse.com,gechangwei@live.cn,joseph.qi@linux.alibaba.com,akpm@linux-foundation.org
Subject: + ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item.patch added to mm-nonmm-unstable branch
Date: Wed, 22 Jul 2026 16:44:01 -0700 [thread overview]
Message-ID: <20260722234401.E2EDB1F000E9@smtp.kernel.org> (raw)
The patch titled
Subject: ocfs2: cluster: avoid lock order inversion in o2hb_region_pin() from drop_item
has been added to the -mm mm-nonmm-unstable branch. Its filename is
ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
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and is updated there most days
------------------------------------------------------
From: Joseph Qi <joseph.qi@linux.alibaba.com>
Subject: ocfs2: cluster: avoid lock order inversion in o2hb_region_pin() from drop_item
Date: Wed, 22 Jul 2026 20:49:32 +0800
o2hb_heartbeat_group_drop_item() is called from configfs rmdir with the
parent directory's inode_lock held. It calls o2hb_region_pin() ->
o2nm_depend_item() -> configfs_depend_item(), which acquires the configfs
root inode_lock. This creates a parent -> root inode_lock nesting that
could deadlock against paths taking root -> parent (e.g. subsystem
unregistration).
Fix this by using configfs_depend_item_unlocked() when o2hb_region_pin()
is called from a configfs callback context. This variant skips the root
inode_lock when caller and target are in the same subsystem, which is safe
because VFS already holds a lock preventing unregistration.
Add o2nm_depend_item_unlocked() wrapper and a from_callback parameter to
o2hb_region_pin() to select the appropriate variant.
Link: https://lore.kernel.org/20260722124933.430554-3-joseph.qi@linux.alibaba.com
Fixes: 58a3158a5d17 ("ocfs2/cluster: Pin/unpin o2hb regions")
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/ocfs2/cluster/heartbeat.c | 17 ++++++++++-------
fs/ocfs2/cluster/nodemanager.c | 6 ++++++
fs/ocfs2/cluster/nodemanager.h | 1 +
3 files changed, 17 insertions(+), 7 deletions(-)
--- a/fs/ocfs2/cluster/heartbeat.c~ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item
+++ a/fs/ocfs2/cluster/heartbeat.c
@@ -146,7 +146,7 @@ static unsigned int o2hb_dependent_users
* In global heartbeat mode, we pin/unpin all o2hb regions. This solution
* works for both file system and userdlm domains.
*/
-static int o2hb_region_pin(const char *region_uuid);
+static int o2hb_region_pin(const char *region_uuid, bool from_callback);
static void o2hb_region_unpin(const char *region_uuid);
/* Only sets a new threshold if there are no active regions.
@@ -2188,7 +2188,7 @@ static void o2hb_heartbeat_group_drop_it
if (bitmap_weight(o2hb_quorum_region_bitmap,
O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
- o2hb_region_pin(NULL);
+ o2hb_region_pin(NULL, true);
unlock:
spin_unlock(&o2hb_live_lock);
@@ -2330,7 +2330,7 @@ EXPORT_SYMBOL_GPL(o2hb_setup_callback);
* In local, we only pin the matching region. In global we pin all the active
* regions.
*/
-static int o2hb_region_pin(const char *region_uuid)
+static int o2hb_region_pin(const char *region_uuid, bool from_callback)
{
int ret = 0, found;
struct o2hb_region *reg, *pinned;
@@ -2385,7 +2385,10 @@ static int o2hb_region_pin(const char *r
spin_unlock(&o2hb_live_lock);
/* Ignore ENOENT only for local hb (userdlm domain) */
- ret = o2nm_depend_item(&pinned->hr_item);
+ if (from_callback)
+ ret = o2nm_depend_item_unlocked(&pinned->hr_item);
+ else
+ ret = o2nm_depend_item(&pinned->hr_item);
spin_lock(&o2hb_live_lock);
if (!ret) {
@@ -2483,8 +2486,8 @@ static int o2hb_region_inc_user(const ch
/* local heartbeat */
if (!o2hb_global_heartbeat_active()) {
- ret = o2hb_region_pin(region_uuid);
- goto unlock;
+ ret = o2hb_region_pin(region_uuid, false);
+ goto unlock;
}
/*
@@ -2497,7 +2500,7 @@ static int o2hb_region_inc_user(const ch
if (bitmap_weight(o2hb_quorum_region_bitmap,
O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
- ret = o2hb_region_pin(NULL);
+ ret = o2hb_region_pin(NULL, false);
unlock:
spin_unlock(&o2hb_live_lock);
--- a/fs/ocfs2/cluster/nodemanager.c~ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item
+++ a/fs/ocfs2/cluster/nodemanager.c
@@ -778,6 +778,12 @@ int o2nm_depend_item(struct config_item
return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item);
}
+int o2nm_depend_item_unlocked(struct config_item *item)
+{
+ return configfs_depend_item_unlocked(&o2nm_cluster_group.cs_subsys,
+ item);
+}
+
void o2nm_undepend_item(struct config_item *item)
{
configfs_undepend_item(item);
--- a/fs/ocfs2/cluster/nodemanager.h~ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item
+++ a/fs/ocfs2/cluster/nodemanager.h
@@ -64,6 +64,7 @@ void o2nm_node_get(struct o2nm_node *nod
void o2nm_node_put(struct o2nm_node *node);
int o2nm_depend_item(struct config_item *item);
+int o2nm_depend_item_unlocked(struct config_item *item);
void o2nm_undepend_item(struct config_item *item);
int o2nm_depend_node(u8 node_num);
void o2nm_undepend_node(u8 node_num);
_
Patches currently in -mm which might be from joseph.qi@linux.alibaba.com are
ocfs2-cluster-use-gfp_nofs-for-heartbeat-bio-allocation.patch
ocfs2-cluster-use-an-on-stack-bio-for-the-heartbeat-write.patch
ocfs2-cluster-dont-sleep-while-holding-o2hb_live_lock-in-o2hb_region_pin.patch
ocfs2-cluster-avoid-lock-order-inversion-in-o2hb_region_pin-from-drop_item.patch
ocfs2-cluster-fix-o2hb_dependent_users-leak-on-pin-failure.patch
reply other threads:[~2026-07-22 23:44 UTC|newest]
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