pidns: remove recursion from free_pid_ns()
free_pid_ns() operates in a recursive fashion: free_pid_ns(parent) put_pid_ns(parent) kref_put(&ns->kref, free_pid_ns); free_pid_ns thus if there was a huge nesting of namespaces the userspace may trigger avalanche calling of free_pid_ns leading to kernel stack exhausting and a panic eventually. This patch turns the recursion into an iterative loop. Based on a patch by Andrew Vagin. [akpm@linux-foundation.org: export put_pid_ns() to modules] Signed-off-by:Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Greg KH <greg@kroah.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
parent
dc36d7e7
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