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f6c7f03f69
The iTXQs stop/wake queue mechanism involves a whole bunch of locks and this is probably why the call to ieee80211_wake_txqs is deferred to a tasklet when called from __ieee80211_wake_queue. Another advantage of that is that ieee80211_wake_txqs might call the wake_tx_queue() callback and then the driver may call mac80211 which will call it back in the same context. The bug I saw is that when we send a deauth frame as a station we do: flush(drop=1) tx deauth flush(drop=0) While we flush we stop the queues and wake them up immediately after we finished flushing. The problem here is that the tasklet that de-facto enables the queue may not have run until we send the deauth. Then the deauth frame is sent to the driver (which is surprising by itself), but the driver won't get anything useful from ieee80211_tx_dequeue because the queue is stopped (or more precisely because vif->txqs_stopped[0] is true). Then the deauth is not sent. Later on, the tasklet will run, but that'll be too late. We'll already have removed all the vif etc... Fix this by calling ieee80211_wake_txqs synchronously if we are not waking up the queues from the driver (we check the reason to determine that). This makes the code really convoluted because we may call ieee80211_wake_txqs from __ieee80211_wake_queue. The latter assumes that queue_stop_reason_lock has been taken by the caller and ieee80211_wake_txqs may release the lock to send the frames. Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> |
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| .get_maintainer.ignore | ||
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| README | ||
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.
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.