From 77819daf247aad16beaeb537ae77d1d6d0697ca2 Mon Sep 17 00:00:00 2001
From: Dmitry Safonov <dima@arista.com>
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 <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20200418201944.482088-48-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 3de0cc780c164..43f5dcd2b9ac7 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--;
}
--
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