From: Dmitry Safonov <dima@xxxxxxxxxx> Subject: um: add show_stack_loglvl() 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. Introduce show_stack_loglvl(), that eventually will substitute show_stack(). [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@xxxxxxxxxx/T/#u Link: http://lkml.kernel.org/r/20200418201944.482088-37-dima@xxxxxxxxxx Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> Cc: Anton Ivanov <anton.ivanov@xxxxxxxxxxxxxxxxxx> Cc: Jeff Dike <jdike@xxxxxxxxxxx> Cc: Richard Weinberger <richard@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/um/kernel/sysrq.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) --- a/arch/um/kernel/sysrq.c~um-add-show_stack_loglvl +++ a/arch/um/kernel/sysrq.c @@ -17,7 +17,9 @@ static void _print_addr(void *data, unsigned long address, int reliable) { - pr_info(" [<%08lx>] %s%pS\n", address, reliable ? "" : "? ", + const char *loglvl = data; + + printk("%s [<%08lx>] %s%pS\n", loglvl, address, reliable ? "" : "? ", (void *)address); } @@ -25,7 +27,8 @@ static const struct stacktrace_ops stack .address = _print_addr }; -void show_stack(struct task_struct *task, unsigned long *stack) +void show_stack_loglvl(struct task_struct *task, unsigned long *stack, + const char *loglvl) { struct pt_regs *segv_regs = current->thread.segv_regs; int i; @@ -39,17 +42,22 @@ void show_stack(struct task_struct *task if (!stack) stack = get_stack_pointer(task, segv_regs); - pr_info("Stack:\n"); + printk("%sStack:\n", loglvl); for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) { if (kstack_end(stack)) break; if (i && ((i % STACKSLOTS_PER_LINE) == 0)) - pr_cont("\n"); + printk("%s\n", loglvl); pr_cont(" %08lx", *stack++); } - pr_cont("\n"); + printk("%s\n", loglvl); + + printk("%sCall Trace:\n", loglvl); + dump_trace(current, &stackops, (void *)loglvl); + printk("%s\n", loglvl); +} - pr_info("Call Trace:\n"); - dump_trace(current, &stackops, NULL); - pr_info("\n"); +void show_stack(struct task_struct *task, unsigned long *stack) +{ + show_stack_loglvl(task, stack, KERN_INFO); } _
