diff options
| author |   Johannes Berg <johannes@sipsolutions.net> | 2008-09-11 00:01:51 +0200 |
|---|---|---|
| committer |   John W. Linville <linville@tuxdriver.com> | 2008-09-15 16:48:20 -0400 |
| commit | 5bc75728fd43bb15b46f16ef465bcf9d487393cf (patch) | |
| tree | 5732adee3965970390bf7953d214c757bbdba2a2 /include | |
| parent | mac80211: fix work race (diff) | |
| download | linux-dev-5bc75728fd43bb15b46f16ef465bcf9d487393cf.tar.xz linux-dev-5bc75728fd43bb15b46f16ef465bcf9d487393cf.zip | |
mac80211: fix scan vs. interface removal race
When we remove an interface, we can currently end up having
a pointer to it left in local->scan_sdata after it has been
set down, and then with a hardware scan the scan completion
can try to access it which is a bug. Alternatively, a scan
that started as a hardware scan may terminate as though it
was a software scan, if the timing is just right.
On SMP systems, software scan also has a similar problem,
just canceling the delayed work and setting a flag isn't
enough since it may be running concurrently; in this case
we would also never restore state of other interfaces.
This patch hopefully fixes the problems by always invoking
ieee80211_scan_completed or requiring it to be invoked by
the driver, I suspect the drivers that have ->hw_scan() are
buggy. The bug will not manifest itself unless you remove
the interface while hw-scanning which will also turn off
the hw, and then add a new interface which will be unusable
until you scan once.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/mac80211.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/net/mac80211.h b/include/net/mac80211.h index f504e3eca7d3..d67882dd3604 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1124,7 +1124,9 @@ enum ieee80211_ampdu_mlme_action { * @hw_scan: Ask the hardware to service the scan request, no need to start * the scan state machine in stack. The scan must honour the channel * configuration done by the regulatory agent in the wiphy's registered - * bands. + * bands. When the scan finishes, ieee80211_scan_completed() must be + * called; note that it also must be called when the scan cannot finish + * because the hardware is turned off! Anything else is a bug! * * @get_stats: return low-level statistics * |