On Mon, 2021-11-29 at 15:12 -0500, Chris Murphy wrote:

On Mon, Nov 29, 2021 at 7:39 AM Hans de Goede [off-list ref] wrote:

quoted

Hi All,

Since kernel 5.15 (IIRC) I've been getting a suspicous RCU usage warning
from the iwlwifi driver when running a kernel with checks for this enabled.

Note this is the 2nd or 3th time this happens now, can we please get
some CI checks for these (assuming there is some iwlwifi CI already) ?

I mentioned it back in October ...
https://lore.kernel.org/linux-wireless/CAJCQCtR28JZaqNC053jEpoZGN37kRK9ReYX0Kt8+ukRGnO5z_Q@mail.gmail.com/ (local)

And it's still happening with 5.16-rc3 out today.

We have this code:

static int iwl_mvm_start_get_nvm(struct iwl_mvm *mvm)
{
        int ret;

        rtnl_lock();
        mutex_lock(&mvm->mutex);


but internally we already have

static int iwl_mvm_start_get_nvm(struct iwl_mvm *mvm)
{
...
        rtnl_lock();
        wiphy_lock(mvm->hw->wiphy);
        mutex_lock(&mvm->mutex);


so that's surely the issue - Luca, do you already have any patches for
this out? It was internally through a merge, so no explicit change, and
I guess upstream I forgot when doing the RTNL work?

johannes