sh: add loglvl to dump_mem()

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_mem() as a preparation to introduce
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: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200418201944.482088-30-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dmitry Safonov 2020-06-08 21:31:24 -07:00 committed by Linus Torvalds
parent 8539c1288d
commit ebf0a36a32
3 changed files with 13 additions and 11 deletions

View file

@ -13,6 +13,7 @@ enum die_val {
/* arch/sh/kernel/dumpstack.c */
extern void printk_address(unsigned long address, int reliable);
extern void dump_mem(const char *str, unsigned long bottom, unsigned long top);
extern void dump_mem(const char *str, const char *loglvl,
unsigned long bottom, unsigned long top);
#endif /* __ASM_SH_KDEBUG_H */

View file

@ -16,30 +16,31 @@
#include <asm/unwinder.h>
#include <asm/stacktrace.h>
void dump_mem(const char *str, unsigned long bottom, unsigned long top)
void dump_mem(const char *str, const char *loglvl,
unsigned long bottom, unsigned long top)
{
unsigned long p;
int i;
printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
printk("%s%s(0x%08lx to 0x%08lx)\n", loglvl, str, bottom, top);
for (p = bottom & ~31; p < top; ) {
printk("%04lx: ", p & 0xffff);
printk("%s%04lx: ", loglvl, p & 0xffff);
for (i = 0; i < 8; i++, p += 4) {
unsigned int val;
if (p < bottom || p >= top)
printk(" ");
printk("%s ", loglvl);
else {
if (__get_user(val, (unsigned int __user *)p)) {
printk("\n");
printk("%s\n", loglvl);
return;
}
printk("%08x ", val);
printk("%s%08x ", loglvl, val);
}
}
printk("\n");
printk("%s\n", loglvl);
}
}
@ -156,7 +157,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
sp = (unsigned long *)tsk->thread.sp;
stack = (unsigned long)sp;
dump_mem("Stack: ", stack, THREAD_SIZE +
dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
(unsigned long)task_stack_page(tsk));
show_trace(tsk, sp, NULL);
}

View file

@ -38,8 +38,8 @@ void die(const char *str, struct pt_regs *regs, long err)
task_pid_nr(current), task_stack_page(current) + 1);
if (!user_mode(regs) || in_interrupt())
dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
(unsigned long)task_stack_page(current));
dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
THREAD_SIZE + (unsigned long)task_stack_page(current));
notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);