On Thu, Mar 19, 2026 at 05:33:50PM +0100, Sebastian Andrzej Siewior wrote: > On 2026-03-19 09:27:59 [-0700], Boqun Feng wrote: > > On Thu, Mar 19, 2026 at 10:03:15AM +0100, Sebastian Andrzej Siewior wrote: > > > Please just use the queue_delayed_work() with a delay >0. > > > > > > > That doesn't work since queue_delayed_work() with a positive delay will > > still acquire timer base lock, and we can have BPF instrument with timer > > base lock held i.e. calling call_srcu() with timer base lock. > > > > irq_work on the other hand doesn't use any locking. > > Could we please restrict BPF somehow so it does roam free? It is > absolutely awful to have irq_work() in call_srcu() just because it > might acquire locks. >
I agree it's not RCU's fault ;-) I guess it'll be difficult to restrict BPF, however maybe BPF can call call_srcu() in irq_work instead? Or a more systematic defer mechanism that allows BPF to defer any lock holding functions to a different context. (We have a similar issue that BPF cannot call kfree_rcu() in some cases IIRC). But we need to fix this in v7.0, so this short-term fix is still needed. Regars, Boqun > > Regards, > > Boqun > > > Sebastian
