Commit 196779b9 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds

dump_stack: consolidate dump_stack() implementations and unify their behaviors

Both dump_stack() and show_stack() are currently implemented by each
architecture.  show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack().  On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.

The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().

There's no reason to require archs to implement two separate but mostly
identical functions.  It leads to unnecessary subtle information.

This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin.  Blackfin's
dump_stack() does something wonky that I don't understand.

Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information.  This is used
in blackfin.

This patch brings the following behavior changes.

* On some archs, an extra level in backtrace for show_stack() could be
  printed.  This is because the top frame was determined in
  dump_stack() on those archs while generic dump_stack() can't do that
  reliably.  It can be compensated by inlining dump_stack() but not
  sure whether that'd be necessary.

* Most archs didn't use to print debug info on dump_stack().  They do
  now.

An example WARN dump follows.

 WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
 Hardware name: empty
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
  0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
  ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
  0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
 Call Trace:
  [<ffffffff81c614dc>] dump_stack+0x19/0x1b
  [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
  [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8234a071>] init_workqueues+0x35/0x505
  ...

v2: CPU number added to the generic debug info as requested by s390
    folks and dropped the s390 specific dump_stack().  This loses %ksp
    from the debug message which the maintainers think isn't important
    enough to keep the s390-specific dump_stack() implementation.

    dump_stack_print_info() is moved to kernel/printk.c from
    lib/dump_stack.c.  Because linkage is per objecct file,
    dump_stack_print_info() living in the same lib file as generic
    dump_stack() means that archs which implement custom dump_stack()
    - at this point, only blackfin - can't use dump_stack_print_info()
    as that will bring in the generic version of dump_stack() too.  v1
    The v1 patch broke build on blackfin due to this issue.  The build
    breakage was reported by Fengguang Wu.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: default avatarVineet Gupta <vgupta@synopsys.com>
Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: default avatarVineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>	[s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org>		[hexagon bits]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 89e3f23d
......@@ -169,13 +169,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
dik_show_trace(sp);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void
die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
{
......
......@@ -220,13 +220,6 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
show_stacktrace(tsk, NULL);
}
/* Expected by Rest of kernel code */
void dump_stack(void)
{
show_stacktrace(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
/* Another API expected by schedular, shows up in "ps" as Wait Channel
* Ofcourse just returning schedule( ) would be pointless so unwind until
* the function is not in schedular code
......
......@@ -204,13 +204,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
}
#endif
void dump_stack(void)
{
dump_backtrace(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
dump_backtrace(NULL, tsk);
......
......@@ -167,13 +167,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
}
}
void dump_stack(void)
{
dump_backtrace(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
dump_backtrace(NULL, tsk);
......
......@@ -204,14 +204,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
}
void dump_stack(void)
{
unsigned long stack;
show_trace_log_lvl(current, &stack, NULL, "");
}
EXPORT_SYMBOL(dump_stack);
static const char *cpu_modes[] = {
"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
......
......@@ -168,6 +168,7 @@ void dump_stack(void)
#endif
trace_buffer_save(tflags);
dump_bfin_trace_buffer();
dump_stack_print_info(KERN_DEFAULT);
show_stack(current, &stack);
trace_buffer_restore(tflags);
}
......
......@@ -67,15 +67,6 @@ void show_regs(struct pt_regs *regs)
pr_err("A31: %08lx B31: %08lx\n", regs->a31, regs->b31);
}
void dump_stack(void)
{
unsigned long stack;
show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
void die(char *str, struct pt_regs *fp, int nr)
{
console_verbose();
......
......@@ -146,13 +146,6 @@ show_stack(void)
}
#endif
void
dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void
set_nmi_handler(void (*handler)(struct pt_regs *))
{
......
......@@ -466,17 +466,6 @@ asmlinkage void compound_exception(unsigned long esfr1,
BUG();
} /* end compound_exception() */
/*****************************************************************************/
/*
* The architecture-independent backtrace generator
*/
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_stack(struct task_struct *task, unsigned long *sp)
{
}
......
......@@ -164,10 +164,3 @@ void show_trace_task(struct task_struct *tsk)
{
show_stack(tsk,(unsigned long *)tsk->thread.esp0);
}
void dump_stack(void)
{
show_stack(NULL,NULL);
}
EXPORT_SYMBOL(dump_stack);
......@@ -191,14 +191,6 @@ void show_stack(struct task_struct *task, unsigned long *fp)
do_show_stack(task, fp, 0);
}
void dump_stack(void)
{
unsigned long *fp;
asm("%0 = r30" : "=r" (fp));
show_stack(current, fp);
}
EXPORT_SYMBOL(dump_stack);
int die(const char *str, struct pt_regs *regs, long err)
{
static struct {
......
......@@ -95,14 +95,6 @@ show_stack (struct task_struct *task, unsigned long *sp)
}
}
void
dump_stack (void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void
show_regs (struct pt_regs *regs)
{
......
......@@ -167,15 +167,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_trace(task, sp);
}
void dump_stack(void)
{
unsigned long stack;
show_trace(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
static void show_registers(struct pt_regs *regs)
{
int i = 0;
......
......@@ -991,18 +991,6 @@ void show_stack(struct task_struct *task, unsigned long *stack)
show_trace(stack);
}
/*
* The architecture-independent backtrace generator
*/
void dump_stack(void)
{
unsigned long stack;
show_trace(&stack);
}
EXPORT_SYMBOL(dump_stack);
/*
* The vector number returned in the frame pointer may also contain
* the "fs" (Fault Status) bits on ColdFire. These are in the bottom
......
......@@ -987,9 +987,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
show_trace(tsk, sp, NULL);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
......@@ -75,9 +75,3 @@ void show_stack(struct task_struct *task, unsigned long *sp)
debug_show_held_locks(task);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
......@@ -206,19 +206,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_stacktrace(task, &regs);
}
/*
* The architecture-independent dump_stack generator
*/
void dump_stack(void)
{
struct pt_regs regs;
prepare_frametrace(&regs);
show_backtrace(current, &regs);
}
EXPORT_SYMBOL(dump_stack);
static void show_code(unsigned int __user *pc)
{
long i;
......
......@@ -293,17 +293,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_trace(sp);
}
/*
* the architecture-independent dump_stack generator
*/
void dump_stack(void)
{
unsigned long stack;
show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
/*
* dump the register file in the specified exception frame
*/
......
......@@ -105,17 +105,6 @@ void show_trace_task(struct task_struct *tsk)
*/
}
/*
* The architecture-independent backtrace generator
*/
void dump_stack(void)
{
unsigned long stack;
show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
void show_registers(struct pt_regs *regs)
{
int i;
......
......@@ -158,14 +158,6 @@ void show_regs(struct pt_regs *regs)
}
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
static void do_show_stack(struct unwind_frame_info *info)
{
int i = 1;
......
......@@ -1362,12 +1362,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
} while (count++ < kstack_depth_to_print);
}
void dump_stack(void)
{
show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
#ifdef CONFIG_PPC64
/* Called with hard IRQs off */
void __ppc64_runlatch_on(void)
......
......@@ -129,23 +129,6 @@ static void show_last_breaking_event(struct pt_regs *regs)
#endif
}
/*
* The architecture-independent dump_stack generator
*/
void dump_stack(void)
{
printk("CPU: %d %s %s %.*s\n",
task_thread_info(current)->cpu, print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
current->comm, current->pid, current,
(void *) current->thread.ksp);
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
{
return (regs->psw.mask & bits) / ((~bits + 1) & bits);
......
......@@ -149,16 +149,6 @@ static void show_registers(struct pt_regs *regs)
printk(KERN_NOTICE "\n");
}
/*
* The architecture-independent dump_stack generator
*/
void dump_stack(void)
{
show_stack(current_thread_info()->task,
(long *) get_irq_regs()->regs[0]);
}
EXPORT_SYMBOL(dump_stack);
void __die(const char *str, struct pt_regs *regs, const char *file,
const char *func, unsigned long line)
{
......
......@@ -158,9 +158,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
(unsigned long)task_stack_page(tsk));
show_trace(tsk, sp, NULL);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
......@@ -164,13 +164,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
printk("\n");
}
void dump_stack(void)
{
show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
/*
* Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
*/
......
......@@ -2350,13 +2350,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
} while (++count < 16);
}
void dump_stack(void)
{
show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
static inline struct reg_window *kernel_stack_up(struct reg_window *rw)
{
unsigned long fp = rw->ins[6];
......
......@@ -35,18 +35,6 @@ void show_trace(struct task_struct *task, unsigned long * stack)
}
#endif
/*
* stack dumps generator - this is used by arch-independent code.
* And this is identical to i386 currently.
*/
void dump_stack(void)
{
unsigned long stack;
show_trace(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
/*Stolen from arch/i386/kernel/traps.c */
static const int kstack_depth_to_print = 24;
......
......@@ -170,12 +170,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
c_backtrace(fp, mode);
}
void dump_stack(void)
{
dump_backtrace(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
dump_backtrace(NULL, tsk);
......
......@@ -191,24 +191,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_stack_log_lvl(task, NULL, sp, bp, "");
}
/*
* The architecture-independent dump_stack generator
*/
void dump_stack(void)
{
unsigned long bp;
unsigned long stack;
bp = stack_frame(current, NULL);
printk("Pid: %d, comm: %.20s %s %s %.*s\n",
current->pid, current->comm, print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
show_trace(NULL, NULL, &stack, bp);
}
EXPORT_SYMBOL(dump_stack);
static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;
......
......@@ -481,14 +481,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_trace(task, stack);
}
void dump_stack(void)
{
show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_code(unsigned int *pc)
{
long i;
......
......@@ -145,6 +145,7 @@ extern void wake_up_klogd(void);
void log_buf_kexec_setup(void);
void __init setup_log_buf(int early);
void dump_stack_print_info(const char *log_lvl);
#else
static inline __printf(1, 0)
int vprintk(const char *s, va_list args)
......@@ -182,6 +183,10 @@ static inline void log_buf_kexec_setup(void)
static inline void setup_log_buf(int early)
{
}
static inline void dump_stack_print_info(const char *log_lvl)
{
}
#endif
extern void dump_stack(void) __cold;
......
......@@ -43,6 +43,7 @@
#include <linux/rculist.h>
#include <linux/poll.h>
#include <linux/irq_work.h>
#include <linux/utsname.h>
#include <asm/uaccess.h>
......@@ -2849,4 +2850,21 @@ void kmsg_dump_rewind(struct kmsg_dumper *dumper)
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
}
EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
/**
* dump_stack_print_info - print generic debug info for dump_stack()
* @log_lvl: log level
*
* Arch-specific dump_stack() implementations can use this function to
* print out the same debug information as the generic dump_stack().
*/
void dump_stack_print_info(const char *log_lvl)
{
printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n",
log_lvl, raw_smp_processor_id(), current->pid, current->comm,
print_tainted(), init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
}
#endif
......@@ -5,11 +5,16 @@
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched.h>
/**
* dump_stack - dump the current task information and its stack trace
*
* Architectures can override this implementation by implementing its own.
*/
void dump_stack(void)
{
printk(KERN_NOTICE
"This architecture does not implement dump_stack()\n");
dump_stack_print_info(KERN_DEFAULT);
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment