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 @@ -306,7 +306,7 @@ 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(); } _
