Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup

From: Peter Zijlstra
Date: Wed Jan 10 2018 - 13:22:29 EST


On Wed, Jan 10, 2018 at 09:02:23AM -0800, Tejun Heo wrote:
> 2. System runs out of memory, OOM triggers.
> 3. OOM handler is printing out OOM debug info.
> 4. While trying to emit the messages for netconsole, the network stack
> / driver tries to allocate memory and then fail, which in turn
> triggers allocation failure or other warning messages. printk was
> already flushing, so the messages are queued on the ring.
> 5. OOM handler keeps flushing but 4 repeats and the queue is never
> shrinking. Because OOM handler is trapped in printk flushing, it
> never manages to free memory and no one else can enter OOM path
> either, so the system is trapped in this state.

Why not kill recursive OOM (msgs) ?