On 2018-08-13 1:20 p.m., Vlad Buslov wrote:
Lockdep reports deadlock for following locking scenario in ife action:
Task one:
1) Executes ife action update.
2) Takes tcfa_lock.
3) Waits on ife_mod_lock which is already taken by task two.
Task two:
1) Executes any path that obtains ife_mod_lock without disabling bh (any
path that takes ife_mod_lock while holding tcfa_lock has bh disabled) like
loading a meta module, or creating new action.
2) Takes ife_mod_lock.
3) Task is preempted by rate estimator timer.
4) Timer callback waits on tcfa_lock which is taken by task one.
In described case tasks deadlock because they take same two locks in
different order. To prevent potential deadlock reported by lockdep, always
disable bh when obtaining ife_mod_lock.
Looks like your recent changes on net-next exposed this.
Acked-by: Jamal Hadi Salim <j...@mojatatu.com>
cheers,
jamal
