The patch titled
Subject: arm64: add loglvl to dump_backtrace()
has been added to the -mm tree. Its filename is
arm64-add-loglvl-to-dump_backtrace.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-add-loglvl-to-dump_backtrace.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-add-loglvl-to-dump_backtrace.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dmitry Safonov <dima@xxxxxxxxxx>
Subject: arm64: add loglvl to dump_backtrace()
Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).
Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages. And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers. Also, it will consolidate
printings with headers.
Add log level argument to dump_backtrace() as a preparation for
introducing show_stack_loglvl().
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@xxxxxxxxxx/T/#u
Link: http://lkml.kernel.org/r/20200418201944.482088-10-dima@xxxxxxxxxx
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/stacktrace.h | 3 ++-
arch/arm64/kernel/process.c | 2 +-
arch/arm64/kernel/traps.c | 15 ++++++++-------
3 files changed, 11 insertions(+), 9 deletions(-)
--- a/arch/arm64/include/asm/stacktrace.h~arm64-add-loglvl-to-dump_backtrace
+++ a/arch/arm64/include/asm/stacktrace.h
@@ -64,7 +64,8 @@ struct stackframe {
extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data);
-extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+ const char *loglvl);
DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
--- a/arch/arm64/kernel/process.c~arm64-add-loglvl-to-dump_backtrace
+++ a/arch/arm64/kernel/process.c
@@ -291,7 +291,7 @@ void __show_regs(struct pt_regs *regs)
void show_regs(struct pt_regs * regs)
{
__show_regs(regs);
- dump_backtrace(regs, NULL);
+ dump_backtrace(regs, NULL, KERN_DEFAULT);
}
static void tls_thread_flush(void)
--- a/arch/arm64/kernel/traps.c~arm64-add-loglvl-to-dump_backtrace
+++ a/arch/arm64/kernel/traps.c
@@ -53,9 +53,9 @@ static const char *handler[]= {
int show_unhandled_signals = 0;
-static void dump_backtrace_entry(unsigned long where)
+static void dump_backtrace_entry(unsigned long where, const char *loglvl)
{
- printk(" %pS\n", (void *)where);
+ printk("%s %pS\n", loglvl, (void *)where);
}
static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
@@ -83,7 +83,8 @@ static void dump_kernel_instr(const char
printk("%sCode: %s\n", lvl, str);
}
-void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+ const char *loglvl)
{
struct stackframe frame;
int skip = 0;
@@ -115,11 +116,11 @@ void dump_backtrace(struct pt_regs *regs
thread_saved_pc(tsk));
}
- printk("Call trace:\n");
+ printk("%sCall trace:\n", loglvl);
do {
/* skip until specified stack frame */
if (!skip) {
- dump_backtrace_entry(frame.pc);
+ dump_backtrace_entry(frame.pc, loglvl);
} else if (frame.fp == regs->regs[29]) {
skip = 0;
/*
@@ -129,7 +130,7 @@ void dump_backtrace(struct pt_regs *regs
* at which an exception has taken place, use regs->pc
* instead.
*/
- dump_backtrace_entry(regs->pc);
+ dump_backtrace_entry(regs->pc, loglvl);
}
} while (!unwind_frame(tsk, &frame));
@@ -138,7 +139,7 @@ void dump_backtrace(struct pt_regs *regs
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
- dump_backtrace(NULL, tsk);
+ dump_backtrace(NULL, tsk, KERN_DEFAULT);
barrier();
}
_
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
