That is possible to get/set registers from any thread,
during regs processing we are polling admin qpair to
get a completion. At the same time, another thread
can also poll admin qpair and that can lead to
undefined behavior.
This patch fixes an issue when bdev_nvme is configured
with io_timeout. If remote target becomes unresponsive
(e.g. due to link down), IO timeout occurs and bdev_nvme
tries to get csts registers in timeout_cb. At the same
time another thread can process adminq, so we may have
2 simultaneous adminq polls. If admin qpair is disconnecting
at that time (RDMA transport) we may destroy resources
twice from different threads.
We don't see a problem with set_regs function but it
won't be redundant to lock mutex in set_regs as well.
Signed-off-by: Alexey Marchuk <alexeymar@nvidia.com>
Change-Id: I7ec3984d25d0249061005533d13b22315b44ddf2
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/13687
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
3512714b3f