diff options
| author | Philipp Reisner <philipp.reisner@linbit.com> | 2012-08-21 22:34:07 +0400 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2012-11-09 17:08:20 +0400 |
| commit | c1fd29a11f433ca8ae37723768016ffe6cdd487b (patch) | |
| tree | d297c9ee730f292a2a789f9bbeceffde075afc26 /drivers/block/drbd/drbd_state.c | |
| parent | 0ee98e2eb0c85f27b6f24a15d59fb54f99a93840 (diff) | |
| download | linux-c1fd29a11f433ca8ae37723768016ffe6cdd487b.tar.xz | |
drbd: Fix a race condition that can lead to a BUG()
If the preconditions for a state change change after the wait_event() we
might hit the BUG() statement in conn_set_state().
With holding the spin_lock while evaluating the condition AND until the
actual state change we ensure the the preconditions can not change anymore.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_state.c')
| -rw-r--r-- | drivers/block/drbd/drbd_state.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c index 4fda4e2024ec..ce1495187f02 100644 --- a/drivers/block/drbd/drbd_state.c +++ b/drivers/block/drbd/drbd_state.c @@ -1710,7 +1710,6 @@ _conn_rq_cond(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state if (test_and_clear_bit(CONN_WD_ST_CHG_FAIL, &tconn->flags)) return SS_CW_FAILED_BY_PEER; - spin_lock_irq(&tconn->req_lock); rv = tconn->cstate != C_WF_REPORT_PARAMS ? SS_CW_NO_NEED : SS_UNKNOWN_ERROR; if (rv == SS_UNKNOWN_ERROR) @@ -1719,8 +1718,6 @@ _conn_rq_cond(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state if (rv == SS_SUCCESS) rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */ - spin_unlock_irq(&tconn->req_lock); - return rv; } @@ -1736,21 +1733,22 @@ conn_cl_wide(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state v set_bit(CONN_WD_ST_CHG_REQ, &tconn->flags); if (conn_send_state_req(tconn, mask, val)) { clear_bit(CONN_WD_ST_CHG_REQ, &tconn->flags); - rv = SS_CW_FAILED_BY_PEER; /* if (f & CS_VERBOSE) print_st_err(mdev, os, ns, rv); */ - goto abort; + mutex_unlock(&tconn->cstate_mutex); + spin_lock_irq(&tconn->req_lock); + return SS_CW_FAILED_BY_PEER; } if (val.conn == C_DISCONNECTING) set_bit(DISCONNECT_SENT, &tconn->flags); - wait_event(tconn->ping_wait, (rv = _conn_rq_cond(tconn, mask, val))); + spin_lock_irq(&tconn->req_lock); + + wait_event_lock_irq(tconn->ping_wait, (rv = _conn_rq_cond(tconn, mask, val)), tconn->req_lock,); clear_bit(CONN_WD_ST_CHG_REQ, &tconn->flags); -abort: mutex_unlock(&tconn->cstate_mutex); - spin_lock_irq(&tconn->req_lock); return rv; } |