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| author | Alexander Aring <aahringo@redhat.com> | 2021-03-01 17:05:09 -0500 |
|---|---|---|
| committer | David Teigland <teigland@redhat.com> | 2021-03-09 08:56:42 -0600 |
| commit | e125fbeb538e5e35a00c6c8150a5361bef34814c (patch) | |
| tree | 773e7c6d5e0f382d346fbac10ba6a28307a2974f /fs/dlm/lowcomms.h | |
| parent | 92c48950b43f4a767388cf87709d8687151a641f (diff) | |
| download | lwn-e125fbeb538e5e35a00c6c8150a5361bef34814c.tar.gz lwn-e125fbeb538e5e35a00c6c8150a5361bef34814c.zip | |
fs: dlm: fix mark setting deadlock
This patch fixes an deadlock issue when dlm_lowcomms_close() is called.
When dlm_lowcomms_close() is called the clusters_root.subsys.su_mutex is
held to remove configfs items. At this time we flushing (e.g.
cancel_work_sync()) the workers of send and recv workqueue. Due the fact
that we accessing configfs items (mark values), these workers will lock
clusters_root.subsys.su_mutex as well which are already hold by
dlm_lowcomms_close() and ends in a deadlock situation.
[67170.703046] ======================================================
[67170.703965] WARNING: possible circular locking dependency detected
[67170.704758] 5.11.0-rc4+ #22 Tainted: G W
[67170.705433] ------------------------------------------------------
[67170.706228] dlm_controld/280 is trying to acquire lock:
[67170.706915] ffff9f2f475a6948 ((wq_completion)dlm_recv){+.+.}-{0:0}, at: __flush_work+0x203/0x4c0
[67170.708026]
but task is already holding lock:
[67170.708758] ffffffffa132f878 (&clusters_root.subsys.su_mutex){+.+.}-{3:3}, at: configfs_rmdir+0x29b/0x310
[67170.710016]
which lock already depends on the new lock.
The new behaviour adds the mark value to the node address configuration
which doesn't require to held the clusters_root.subsys.su_mutex by
accessing mark values in a separate datastructure. However the mark
values can be set now only after a node address was set which is the
case when the user is using dlm_controld.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm/lowcomms.h')
| -rw-r--r-- | fs/dlm/lowcomms.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h index 0918f9376489..790d6703b17e 100644 --- a/fs/dlm/lowcomms.h +++ b/fs/dlm/lowcomms.h @@ -21,6 +21,7 @@ int dlm_lowcomms_close(int nodeid); void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc); void dlm_lowcomms_commit_buffer(void *mh); int dlm_lowcomms_connect_node(int nodeid); +int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark); int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len); #endif /* __LOWCOMMS_DOT_H__ */ |