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| author | Philipp Reisner <philipp.reisner@linbit.com> | 2010-06-02 14:31:29 +0200 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2010-06-14 12:19:41 +0200 |
| commit | dc66c74de6f4238020db3e2041d4aca5c5b3e9bc (patch) | |
| tree | 8df9cdd2f1672217a210e624f4613744e57450e0 | |
| parent | 7e27d6e778cd87b6f2415515d7127eba53fe5d02 (diff) | |
| download | kernel_samsung_smdk4412-dc66c74de6f4238020db3e2041d4aca5c5b3e9bc.zip kernel_samsung_smdk4412-dc66c74de6f4238020db3e2041d4aca5c5b3e9bc.tar.gz kernel_samsung_smdk4412-dc66c74de6f4238020db3e2041d4aca5c5b3e9bc.tar.bz2 | |
drbd: Fixed a race between disk-attach and unexpected state changes
This was a very hard to trigger race condition.
If we got a state packet from the peer, after drbd_nl_disk() has
already changed the disk state to D_NEGOTIATING but
after_state_ch() was not yet run by the worker, then receive_state()
might called drbd_sync_handshake(), which in turn crashed
when accessing p_uuid.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
| -rw-r--r-- | drivers/block/drbd/drbd_main.c | 2 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_nl.c | 6 | ||||
| -rw-r--r-- | include/linux/drbd.h | 2 |
3 files changed, 7 insertions, 3 deletions
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 6b077f9..7258c95 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -1236,8 +1236,6 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os, /* Last part of the attaching process ... */ if (ns.conn >= C_CONNECTED && os.disk == D_ATTACHING && ns.disk == D_NEGOTIATING) { - kfree(mdev->p_uuid); /* We expect to receive up-to-date UUIDs soon. */ - mdev->p_uuid = NULL; /* ...to not use the old ones in the mean time */ drbd_send_sizes(mdev, 0, 0); /* to start sync... */ drbd_send_uuids(mdev); drbd_send_state(mdev); diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 632e324..2151f18 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1114,6 +1114,12 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp mdev->new_state_tmp.i = ns.i; ns.i = os.i; ns.disk = D_NEGOTIATING; + + /* We expect to receive up-to-date UUIDs soon. + To avoid a race in receive_state, free p_uuid while + holding req_lock. I.e. atomic with the state change */ + kfree(mdev->p_uuid); + mdev->p_uuid = NULL; } rv = _drbd_set_state(mdev, ns, CS_VERBOSE, NULL); diff --git a/include/linux/drbd.h b/include/linux/drbd.h index 30da4ae..b8d2516 100644 --- a/include/linux/drbd.h +++ b/include/linux/drbd.h @@ -53,7 +53,7 @@ extern const char *drbd_buildtag(void); -#define REL_VERSION "8.3.8rc2" +#define REL_VERSION "8.3.8" #define API_VERSION 88 #define PRO_VERSION_MIN 86 #define PRO_VERSION_MAX 94 |