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| author |   Xue jiufei <xuejiufei@huawei.com> | 2016-01-14 15:17:18 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-14 16:00:49 -0800 |
| commit | 30bee898f86506893883ffb8db20d8101a29b5f5 (patch) | |
| tree | d1998a65a4373824d785773e6a9c2e7b504b01b5 /fs/ocfs2 | |
| parent | ocfs2: o2hb: increase unsteady iterations (diff) | |
| download | linux-dev-30bee898f86506893883ffb8db20d8101a29b5f5.tar.xz linux-dev-30bee898f86506893883ffb8db20d8101a29b5f5.zip | |
ocfs2/dlm: fix a race between purge and migration
We found a race between purge and migration when doing code review.
Node A put lockres to purgelist before receiving the migrate message
from node B which is the master. Node A call dlm_mig_lockres_handler to
handle this message.
dlm_mig_lockres_handler
dlm_lookup_lockres
>>>>>> race window, dlm_run_purge_list may run and send
deref message to master, waiting the response
spin_lock(&res->spinlock);
res->state |= DLM_LOCK_RES_MIGRATING;
spin_unlock(&res->spinlock);
dlm_mig_lockres_handler returns
>>>>>> dlm_thread receives the response from master for the deref
message and triggers the BUG because the lockres has the state
DLM_LOCK_RES_MIGRATING with the following message:
dlm_purge_lockres:209 ERROR: 6633EB681FA7474A9C280A4E1A836F0F: res
M0000000000000000030c0300000000 in use after deref
Signed-off-by: Jiufei Xue <xuejiufei@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2')
| -rw-r--r-- | fs/ocfs2/dlm/dlmrecovery.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c index 9e4f862d20fe..86fb53614bf4 100644 --- a/fs/ocfs2/dlm/dlmrecovery.c +++ b/fs/ocfs2/dlm/dlmrecovery.c @@ -1373,6 +1373,7 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data, char *buf = NULL; struct dlm_work_item *item = NULL; struct dlm_lock_resource *res = NULL; + unsigned int hash; if (!dlm_grab(dlm)) return -EINVAL; @@ -1400,7 +1401,10 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data, /* lookup the lock to see if we have a secondary queue for this * already... just add the locks in and this will have its owner * and RECOVERY flag changed when it completes. */ - res = dlm_lookup_lockres(dlm, mres->lockname, mres->lockname_len); + hash = dlm_lockid_hash(mres->lockname, mres->lockname_len); + spin_lock(&dlm->spinlock); + res = __dlm_lookup_lockres(dlm, mres->lockname, mres->lockname_len, + hash); if (res) { /* this will get a ref on res */ /* mark it as recovering/migrating and hash it */ @@ -1421,13 +1425,16 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data, mres->lockname_len, mres->lockname); ret = -EFAULT; spin_unlock(&res->spinlock); + spin_unlock(&dlm->spinlock); dlm_lockres_put(res); goto leave; } res->state |= DLM_LOCK_RES_MIGRATING; } spin_unlock(&res->spinlock); + spin_unlock(&dlm->spinlock); } else { + spin_unlock(&dlm->spinlock); /* need to allocate, just like if it was * mastered here normally */ res = dlm_new_lockres(dlm, mres->lockname, mres->lockname_len); |