path: root/arch/arm64
diff options
authorDmitry Safonov <dima@arista.com>2020-06-08 21:30:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:11 -0700
commitc76898373f9b71586edaf150190c493ae9ed3e77 (patch)
tree2d501dcc4fbcb66c6c3264849965c40e4e14a1be /arch/arm64
parenta4502d04c7dd075846bb70ebfde3843f9df86f98 (diff)
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@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200418201944.482088-10-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm64')
3 files changed, 11 insertions, 9 deletions
diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 5017b531a415..fc7613023c19 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/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);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index eade7807e819..6089638c7d43 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -306,7 +306,7 @@ void __show_regs(struct pt_regs *regs)
void show_regs(struct pt_regs * regs)
- dump_backtrace(regs, NULL);
+ dump_backtrace(regs, NULL, KERN_DEFAULT);
static void tls_thread_flush(void)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index d332590f5978..f602aca64baa 100644
--- a/arch/arm64/kernel/traps.c
+++ b/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 *lvl, struct pt_regs *regs)
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, struct task_struct *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, struct task_struct *tsk)
* 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, struct task_struct *tsk)
void show_stack(struct task_struct *tsk, unsigned long *sp)
- dump_backtrace(NULL, tsk);
+ dump_backtrace(NULL, tsk, KERN_DEFAULT);