diff options
| author | John Ogness <john.ogness@linutronix.de> | 2024-09-04 14:11:30 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-09-04 15:56:32 +0200 |
| commit | 5102981d5e2a5a7a12424b5d26c7524ac2899898 (patch) | |
| tree | 546c0a008b95bc7241f81366856663fe553372e0 /include/linux/console.h | |
| parent | 75d430372abba5210fbc56a813d2515c001a4f45 (diff) | |
printk: nbcon: Show replay message on takeover
An emergency or panic context can takeover console ownership
while the current owner was printing a printk message. The
atomic printer will re-print the message that the previous
owner was printing. However, this can look confusing to the
user and may even seem as though a message was lost.
[3430014.1
[3430014.181123] usb 1-2: Product: USB Audio
Add a new field @nbcon_prev_seq to struct console to track
the sequence number to print that was assigned to the previous
console owner. If this matches the sequence number to print
that the current owner is assigned, then a takeover must have
occurred. In this case, print an additional message to inform
the user that the previous message is being printed again.
[3430014.1
** replaying previous printk message **
[3430014.181123] usb 1-2: Product: USB Audio
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-12-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'include/linux/console.h')
| -rw-r--r-- | include/linux/console.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/console.h b/include/linux/console.h index 788ce9c829f6..eba367bf605d 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -325,6 +325,7 @@ struct nbcon_write_context { * @nbcon_state: State for nbcon consoles * @nbcon_seq: Sequence number of the next record for nbcon to print * @nbcon_device_ctxt: Context available for non-printing operations + * @nbcon_prev_seq: Seq num the previous nbcon owner was assigned to print * @pbufs: Pointer to nbcon private buffer * @kthread: Printer kthread for this console * @rcuwait: RCU-safe wait object for @kthread waking @@ -459,6 +460,7 @@ struct console { atomic_t __private nbcon_state; atomic_long_t __private nbcon_seq; struct nbcon_context __private nbcon_device_ctxt; + atomic_long_t __private nbcon_prev_seq; struct printk_buffers *pbufs; struct task_struct *kthread; |