[PATCH printk 5/6] printk: Add panic+kexec flush point

[John Ogness]

During panic, nbcon consoles transition to atomic printing. However,
there are consoles that do not support safe atomic printing
(CON_NBCON_ATOMIC_UNSAFE). Such consoles will only flush during
panic if their unsafe flush policy allows them to do so.

The unsafe flush policy NBCON_PANIC_FLUSH only allows unsafe
flushing when particular flushes are explicitly invoked. Call
printk_trigger_flush(PR_FLUSH_RESTART) before performing the kexec
in order to give such consoles a chance to perform an unsafe flush.

Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
---
 kernel/crash_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index d0bd2d0cf8990..064b0af903c38 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -140,6 +140,7 @@ void __noclone __crash_kexec(struct pt_regs *regs)
 
 			crash_setup_regs(&fixed_regs, regs);
 			crash_save_vmcoreinfo();
+			printk_trigger_flush(PR_FLUSH_RESTART);
 			machine_crash_shutdown(&fixed_regs);
 			crash_cma_clear_pending_dma();
 			machine_kexec(kexec_crash_image);
-- 
2.47.3