From 77819daf247aad16beaeb537ae77d1d6d0697ca2 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 8 Jun 2020 21:32:19 -0700 Subject: [PATCH] kdb: don't play with console_loglevel Print the stack trace with KERN_EMERG - it should be always visible. Playing with console_loglevel is a bad idea as there may be more messages printed than wanted. Also the stack trace might be not printed at all if printk() was deferred and console_loglevel was raised back before the trace got flushed. Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master"), kdb_show_stack() uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it uses dump_stack() instead of show_stack(). Convert for now the branch that uses show_stack() and remove console_loglevel exercise from that case. Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Reviewed-by: Douglas Anderson Acked-by: Daniel Thompson Cc: Jason Wessel Link: http://lkml.kernel.org/r/20200418201944.482088-48-dima@arista.com Signed-off-by: Linus Torvalds --- kernel/debug/kdb/kdb_bt.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c index 3de0cc780c16..43f5dcd2b9ac 100644 --- a/kernel/debug/kdb/kdb_bt.c +++ b/kernel/debug/kdb/kdb_bt.c @@ -21,17 +21,18 @@ static void kdb_show_stack(struct task_struct *p, void *addr) { - int old_lvl = console_loglevel; - - console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; kdb_trap_printk++; - if (!addr && kdb_task_has_cpu(p)) + if (!addr && kdb_task_has_cpu(p)) { + int old_lvl = console_loglevel; + + console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; kdb_dump_stack_on_cpu(kdb_process_cpu(p)); - else - show_stack(p, addr); + console_loglevel = old_lvl; + } else { + show_stack_loglvl(p, addr, KERN_EMERG); + } - console_loglevel = old_lvl; kdb_trap_printk--; } -- 2.20.1