On Mon, 2009-05-11 at 08:54 -0400, John W. Linville wrote: > On Sun, May 10, 2009 at 01:00:17PM +0200, Johannes Berg wrote: > > Currently, get_wireless_stats is racy by _design_. This is > > because it returns a buffer, which needs to be statically > > allocated since it cannot be freed if it was allocated > > dynamically. Also, SIOCGIWSTATS and /proc/net/wireless use > > no common lock, and /proc/net/wireless accesses are not > > synchronised against each other. This is a design flaw in > > get_wireless_stats since the beginning. > > > > This patch fixes it by wrapping /proc/net/wireless accesses > > with the RTNL so they are protected against each other and > > SIOCGIWSTATS. The more correct method of fixing this would > > be to pass in the buffer instead of returning it and have > > the caller take care of synchronisation of the buffer, but > > even then most drivers probably assume that their callback > > is protected by the RTNL like all other wext callbacks. > > > > Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> > > Is it acceptable to hold rtnl between ->open and ->release? Hmm. It worked for me, but now I'm having doubts. This stuff confuses me. I'll check it out. johannes
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