7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: John Ogness [ Upstream commit 5f339c46f153184570f16c8e789c9709b14cbe8b ] There have been various bug reports related to SMP systems hanging on boot. The reports vary but seem to have some overlap with regard to missed IPI's during SMP setup. The reports also show that reverting NBCON console usage allows the bugs to disappear. The NBCON kthreads for console printing are started very early during boot using early_initcall(). Since these kthreads are asynchronously enabling/disabling interrupts during early boot, they may be interfering with early SMP setup on some hardware platforms. Starting the console printing kthreads later has shown to avoid the hanging on systems that could previously reproduce the issue. Postpone kthread starting until after all arch initcalls have completed. Reported-by: Derek Barbosa Closes: https://lore.kernel.org/linux-rt-users/arPmYPbFLf2EldIl@debarbos-thinkpadt14gen5.rmtusma.csb Fixes: 76f258bf3f2a ("printk: nbcon: Introduce printer kthreads") Signed-off-by: John Ogness Tested-by: Derek Barbosa Link: https://patch.msgid.link/20261016085441.857695-1-john.ogness@linutronix.de Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin --- kernel/printk/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 96ff9547e888b..fbcfd3e1a1884 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3862,7 +3862,7 @@ static int __init printk_set_kthreads_ready(void) return 0; } -early_initcall(printk_set_kthreads_ready); +subsys_initcall(printk_set_kthreads_ready); #endif /* CONFIG_PRINTK */ static int __read_mostly keep_bootcon; -- 2.53.0