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mips: add show_stack_loglvl()

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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@arista.com/T/#u

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-22-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dmitry Safonov 2020-06-08 21:30:59 -07:00 committed by Linus Torvalds
parent 35f3968b49
commit 96f0458a96
1 changed files with 24 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
arch/mips/kernel/traps.c
View File

@ -108,26 +108,26 @@ void (*board_bind_eic_interrupt)(int irq, int regset);
void (*board_ebase_setup)(void);
void(*board_cache_error_setup)(void);
static void show_raw_backtrace(unsigned long reg29)
static void show_raw_backtrace(unsigned long reg29, const char *loglvl)
{
unsigned long *sp = (unsigned long *)(reg29 & ~3);
unsigned long addr;
printk("Call Trace:");
printk("%sCall Trace:", loglvl);
#ifdef CONFIG_KALLSYMS
printk("\n");
printk("%s\n", loglvl);
#endif
while (!kstack_end(sp)) {
unsigned long __user *p =
(unsigned long __user *)(unsigned long)sp++;
if (__get_user(addr, p)) {
printk(" (Bad stack address)");
printk("%s (Bad stack address)", loglvl);
break;
}
if (__kernel_text_address(addr))
print_ip_sym(KERN_DEFAULT, addr);
print_ip_sym(loglvl, addr);
}
printk("\n");
printk("%s\n", loglvl);
}
#ifdef CONFIG_KALLSYMS
@ -140,7 +140,8 @@ static int __init set_raw_show_trace(char *str)
__setup("raw_show_trace", set_raw_show_trace);
#endif
static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
const char *loglvl)
{
unsigned long sp = regs->regs[29];
unsigned long ra = regs->regs[31];
@ -150,12 +151,12 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
task = current;
if (raw_show_trace || user_mode(regs) || !__kernel_text_address(pc)) {
show_raw_backtrace(sp);
show_raw_backtrace(sp, loglvl);
return;
}
printk("Call Trace:\n");
printk("%sCall Trace:\n", loglvl);
do {
print_ip_sym(KERN_DEFAULT, pc);
print_ip_sym(loglvl, pc);
pc = unwind_stack(task, &sp, pc, &ra);
} while (pc);
pr_cont("\n");
@ -166,19 +167,19 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
* with at least a bit of error checking ...
*/
static void show_stacktrace(struct task_struct *task,
const struct pt_regs *regs)
const struct pt_regs *regs, const char *loglvl)
{
const int field = 2 * sizeof(unsigned long);
long stackdata;
int i;
unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
printk("Stack :");
printk("%sStack :", loglvl);
i = 0;
while ((unsigned long) sp & (PAGE_SIZE - 1)) {
if (i && ((i % (64 / field)) == 0)) {
pr_cont("\n");
printk(" ");
printk("%s ", loglvl);
}
if (i > 39) {
pr_cont(" ...");
@ -194,10 +195,11 @@ static void show_stacktrace(struct task_struct *task,
i++;
}
pr_cont("\n");
show_backtrace(task, regs);
show_backtrace(task, regs, loglvl);
}
void show_stack(struct task_struct *task, unsigned long *sp)
void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
const char *loglvl)
{
struct pt_regs regs;
mm_segment_t old_fs = get_fs();
@ -221,10 +223,15 @@ void show_stack(struct task_struct *task, unsigned long *sp)
* the stack in the kernel (not user) address space.
*/
set_fs(KERNEL_DS);
show_stacktrace(task, &regs);
show_stacktrace(task, &regs, loglvl);
set_fs(old_fs);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
show_stack_loglvl(task, sp, KERN_DEFAULT)
}
static void show_code(unsigned int __user *pc)
{
long i;
@ -373,7 +380,7 @@ void show_registers(struct pt_regs *regs)
if (!user_mode(regs))
/* Necessary for getting the correct stack content */
set_fs(KERNEL_DS);
show_stacktrace(current, regs);
show_stacktrace(current, regs, KERN_DEFAULT);
show_code((unsigned int __user *) regs->cp0_epc);
printk("\n");
set_fs(old_fs);