42116705a7
Initially in this code, the race didn't matter since it didn't
do anything. Latest with the commit I marked this as fixing it
started to matter as something got done here that needed other
data that got freed as soon as the queue notification wait was
returning.
In the scenario we saw, apparently the IWL_MVM_RXQ_NOTIF_DEL_BA
event was sent to all queues, but processing the last event we
returned from iwl_mvm_sync_rx_queues_internal() and then from
iwl_mvm_free_reorder() and continued some processing before
wl_mvm_del_ba() was even invoked on the other CPU. Thus, when
the latter finally ran, it found that mvm->baid_map[baid] was
no longer valid.
Correct the race by moving the counter decrement and wake_up()
to be done only after all the per-event processing completed.
Note that in the commit I marked as being fixed the wake_up()
didn't exist yet (and the code was otherwise problematic) but
this particular problem already existed in a way.
Fixes: b915c10174fb ("iwlwifi: mvm: add reorder buffer per queue")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.