The patch titled
Subject: kdb: don't play with console_loglevel
has been added to the -mm tree. Its filename is
kdb-dont-play-with-console_loglevel.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kdb-dont-play-with-console_loglevel.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kdb-dont-play-with-console_loglevel.patch
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The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dmitry Safonov <dima@xxxxxxxxxx>
Subject: 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.
Link: http://lkml.kernel.org/r/20200418201944.482088-48-dima@xxxxxxxxxx
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/debug/kdb/kdb_bt.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
--- a/kernel/debug/kdb/kdb_bt.c~kdb-dont-play-with-console_loglevel
+++ a/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--;
}
_
Patches currently in -mm which might be from dima@xxxxxxxxxx are
kallsyms-printk-add-loglvl-to-print_ip_sym.patch
alpha-add-show_stack_loglvl.patch
arc-add-show_stack_loglvl.patch
arm-asm-add-loglvl-to-c_backtrace.patch
arm-add-loglvl-to-unwind_backtrace.patch
arm-add-loglvl-to-dump_backtrace.patch
arm-wire-up-dump_backtrace_entrystm.patch
arm-add-show_stack_loglvl.patch
arm64-add-loglvl-to-dump_backtrace.patch
arm64-add-show_stack_loglvl.patch
c6x-add-show_stack_loglvl.patch
csky-add-show_stack_loglvl.patch
h8300-add-show_stack_loglvl.patch
hexagon-add-show_stack_loglvl.patch
ia64-pass-log-level-as-arg-into-ia64_do_show_stack.patch
ia64-add-show_stack_loglvl.patch
m68k-add-show_stack_loglvl.patch
microblaze-add-loglvl-to-microblaze_unwind_inner.patch
microblaze-add-loglvl-to-microblaze_unwind.patch
microblaze-add-show_stack_loglvl.patch
mips-add-show_stack_loglvl.patch
nds32-add-show_stack_loglvl.patch
nios2-add-show_stack_loglvl.patch
openrisc-add-show_stack_loglvl.patch
parisc-add-show_stack_loglvl.patch
powerpc-add-show_stack_loglvl.patch
riscv-add-show_stack_loglvl.patch
s390-add-show_stack_loglvl.patch
sh-add-loglvl-to-dump_mem.patch
sh-remove-needless-printk.patch
sh-add-loglvl-to-printk_address.patch
sh-add-loglvl-to-show_trace.patch
sh-add-show_stack_loglvl.patch
sparc-add-show_stack_loglvl.patch
um-sysrq-remove-needless-variable-sp.patch
um-add-show_stack_loglvl.patch
unicore32-remove-unused-pmode-argument-in-c_backtrace.patch
unicore32-add-loglvl-to-c_backtrace.patch
unicore32-add-show_stack_loglvl.patch
x86-add-missing-const-qualifiers-for-log_lvl.patch
x86-add-show_stack_loglvl.patch
xtensa-add-loglvl-to-show_trace.patch
xtensa-add-show_stack_loglvl.patch
sysrq-use-show_stack_loglvl.patch
x86-amd_gart-print-stacktrace-for-a-leak-with-kern_err.patch
power-use-show_stack_loglvl.patch
kdb-dont-play-with-console_loglevel.patch
sched-print-stack-trace-with-kern_info.patch
kernel-use-show_stack_loglvl.patch
kernel-rename-show_stack_loglvl-=-show_stack.patch
