This is a note to let you know that I've just added the patch titled
wifi: cfg80211: fix missing interfaces when dumping
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
wifi-cfg80211-fix-missing-interfaces-when-dumping.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 653c4dedca61b312e11b899c4b9298461be56f19
Author: Michal Kazior <michal@xxxxxxxxx>
Date: Tue Jan 16 14:22:57 2024 +0000
wifi: cfg80211: fix missing interfaces when dumping
[ Upstream commit a6e4f85d3820d00694ed10f581f4c650445dbcda ]
The nl80211_dump_interface() supports resumption
in case nl80211_send_iface() doesn't have the
resources to complete its work.
The logic would store the progress as iteration
offsets for rdev and wdev loops.
However the logic did not properly handle
resumption for non-last rdev. Assuming a system
with 2 rdevs, with 2 wdevs each, this could
happen:
dump(cb=[0, 0]):
if_start=cb[1] (=0)
send rdev0.wdev0 -> ok
send rdev0.wdev1 -> yield
cb[1] = 1
dump(cb=[0, 1]):
if_start=cb[1] (=1)
send rdev0.wdev1 -> ok
// since if_start=1 the rdev0.wdev0 got skipped
// through if_idx < if_start
send rdev1.wdev1 -> ok
The if_start needs to be reset back to 0 upon wdev
loop end.
The problem is actually hard to hit on a desktop,
and even on most routers. The prerequisites for
this manifesting was:
- more than 1 wiphy
- a few handful of interfaces
- dump without rdev or wdev filter
I was seeing this with 4 wiphys 9 interfaces each.
It'd miss 6 interfaces from the last wiphy
reported to userspace.
Signed-off-by: Michal Kazior <michal@xxxxxxxxx>
Link: https://msgid.link/20240116142340.89678-1-kazikcz@xxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0926a30bc7391..494de0161d2fc 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3350,6 +3350,7 @@ static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *
if_idx++;
}
+ if_start = 0;
wp_idx++;
}
out:
