On Wed, Sep 10, 2025 at 05:12:43PM +0200, Petr Mladek wrote:

On Wed 2025-09-10 14:28:40, John Ogness wrote:

quoted

@pmladek: We could introduce a new console flag (NBCON_ATOMIC_UNSAFE) so
that the callback is only used by nbcon_atomic_flush_unsafe().

This might be an acceptable compromise. It would try to emit messages
only at the very end of panic() as the last desperate attempt.

Just to be sure, what do you mean with unsafe?

    + taking IRQ unsafe locks?

Taking IRQ unsafe locks is the major issue we have in netconsole today.
Basically the drivers can implement IRQ unsafe locks in their
.ndo_start_xmit() callback, and in some cases those are IRQ unsafe,
which doesn't match with .write_atomic(), which expect all the inner
locks to be IRQ safe.