On Thu, 2018-03-08 at 16:50 +0800, Wen Yang wrote: > When scsi disks went wrong frequently, and with serial console > attached, tasks may be blocked in the following flow for more than 10s: [ ... ] >From https://bugzilla.kernel.org/show_bug.cgi?id=199003: "Hm, printk_deferred is a bit dangerous; it moves console_unlock() to IRQ. [ ... ] So I'd say that those two approaches printk_deferred + touch_nmi_watchdog combined can do quite some harm. One thing for sure - they don't really fix any problems." Does that mean that this patch should be dropped? Thanks, Bart.