On Tue, May 30, 2017 at 11:38:12AM +0200, Florian Westphal wrote: > Quoting Joe Stringer: > If a user loads nf_conntrack_ftp, sends FTP traffic through a network > namespace, destroys that namespace then unloads the FTP helper module, > then the kernel will crash. > > Events that lead to the crash: > 1. conntrack is created with ftp helper in netns x > 2. This netns is destroyed > 3. netns destruction is scheduled > 4. netns destruction wq starts, removes netns from global list > 5. ftp helper is unloaded, which resets all helpers of the conntracks > via for_each_net() > > but because netns is already gone from list the for_each_net() loop > doesn't include it, therefore all of these conntracks are unaffected. > > 6. helper module unload finishes > 7. netns wq invokes destructor for rmmod'ed helper
Applied, thanks everyone.
