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htejuntorvalds
htejun
authored and
torvalds
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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+ hardkernel#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: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Vineet 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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33 files changed

+32
-262
lines changed

33 files changed

+32
-262
lines changed

‎arch/alpha/kernel/traps.c

-7
Original file line numberDiff line numberDiff line change
@@ -169,13 +169,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
169169
dik_show_trace(sp);
170170
}
171171

172-
void dump_stack(void)
173-
{
174-
show_stack(NULL, NULL);
175-
}
176-
177-
EXPORT_SYMBOL(dump_stack);
178-
179172
void
180173
die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
181174
{

‎arch/arc/kernel/stacktrace.c

-7
Original file line numberDiff line numberDiff line change
@@ -220,13 +220,6 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
220220
show_stacktrace(tsk, NULL);
221221
}
222222

223-
/* Expected by Rest of kernel code */
224-
void dump_stack(void)
225-
{
226-
show_stacktrace(NULL, NULL);
227-
}
228-
EXPORT_SYMBOL(dump_stack);
229-
230223
/* Another API expected by schedular, shows up in "ps" as Wait Channel
231224
* Ofcourse just returning schedule( ) would be pointless so unwind until
232225
* the function is not in schedular code

‎arch/arm/kernel/traps.c

-7
Original file line numberDiff line numberDiff line change
@@ -204,13 +204,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
204204
}
205205
#endif
206206

207-
void dump_stack(void)
208-
{
209-
dump_backtrace(NULL, NULL);
210-
}
211-
212-
EXPORT_SYMBOL(dump_stack);
213-
214207
void show_stack(struct task_struct *tsk, unsigned long *sp)
215208
{
216209
dump_backtrace(NULL, tsk);

‎arch/arm64/kernel/traps.c

-7
Original file line numberDiff line numberDiff line change
@@ -167,13 +167,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
167167
}
168168
}
169169

170-
void dump_stack(void)
171-
{
172-
dump_backtrace(NULL, NULL);
173-
}
174-
175-
EXPORT_SYMBOL(dump_stack);
176-
177170
void show_stack(struct task_struct *tsk, unsigned long *sp)
178171
{
179172
dump_backtrace(NULL, tsk);

‎arch/avr32/kernel/process.c

-8
Original file line numberDiff line numberDiff line change
@@ -204,14 +204,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
204204
show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
205205
}
206206

207-
void dump_stack(void)
208-
{
209-
unsigned long stack;
210-
211-
show_trace_log_lvl(current, &stack, NULL, "");
212-
}
213-
EXPORT_SYMBOL(dump_stack);
214-
215207
static const char *cpu_modes[] = {
216208
"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
217209
"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"

‎arch/blackfin/kernel/dumpstack.c

+1
Original file line numberDiff line numberDiff line change
@@ -168,6 +168,7 @@ void dump_stack(void)
168168
#endif
169169
trace_buffer_save(tflags);
170170
dump_bfin_trace_buffer();
171+
dump_stack_print_info(KERN_DEFAULT);
171172
show_stack(current, &stack);
172173
trace_buffer_restore(tflags);
173174
}

‎arch/c6x/kernel/traps.c

-9
Original file line numberDiff line numberDiff line change
@@ -67,15 +67,6 @@ void show_regs(struct pt_regs *regs)
6767
pr_err("A31: %08lx B31: %08lx\n", regs->a31, regs->b31);
6868
}
6969

70-
void dump_stack(void)
71-
{
72-
unsigned long stack;
73-
74-
show_stack(current, &stack);
75-
}
76-
EXPORT_SYMBOL(dump_stack);
77-
78-
7970
void die(char *str, struct pt_regs *fp, int nr)
8071
{
8172
console_verbose();

‎arch/cris/kernel/traps.c

-7
Original file line numberDiff line numberDiff line change
@@ -146,13 +146,6 @@ show_stack(void)
146146
}
147147
#endif
148148

149-
void
150-
dump_stack(void)
151-
{
152-
show_stack(NULL, NULL);
153-
}
154-
EXPORT_SYMBOL(dump_stack);
155-
156149
void
157150
set_nmi_handler(void (*handler)(struct pt_regs *))
158151
{

‎arch/frv/kernel/traps.c

-11
Original file line numberDiff line numberDiff line change
@@ -466,17 +466,6 @@ asmlinkage void compound_exception(unsigned long esfr1,
466466
BUG();
467467
} /* end compound_exception() */
468468

469-
/*****************************************************************************/
470-
/*
471-
* The architecture-independent backtrace generator
472-
*/
473-
void dump_stack(void)
474-
{
475-
show_stack(NULL, NULL);
476-
}
477-
478-
EXPORT_SYMBOL(dump_stack);
479-
480469
void show_stack(struct task_struct *task, unsigned long *sp)
481470
{
482471
}

‎arch/h8300/kernel/traps.c

-7
Original file line numberDiff line numberDiff line change
@@ -164,10 +164,3 @@ void show_trace_task(struct task_struct *tsk)
164164
{
165165
show_stack(tsk,(unsigned long *)tsk->thread.esp0);
166166
}
167-
168-
void dump_stack(void)
169-
{
170-
show_stack(NULL,NULL);
171-
}
172-
173-
EXPORT_SYMBOL(dump_stack);

‎arch/hexagon/kernel/traps.c

-8
Original file line numberDiff line numberDiff line change
@@ -191,14 +191,6 @@ void show_stack(struct task_struct *task, unsigned long *fp)
191191
do_show_stack(task, fp, 0);
192192
}
193193

194-
void dump_stack(void)
195-
{
196-
unsigned long *fp;
197-
asm("%0 = r30" : "=r" (fp));
198-
show_stack(current, fp);
199-
}
200-
EXPORT_SYMBOL(dump_stack);
201-
202194
int die(const char *str, struct pt_regs *regs, long err)
203195
{
204196
static struct {

‎arch/ia64/kernel/process.c

-8
Original file line numberDiff line numberDiff line change
@@ -95,14 +95,6 @@ show_stack (struct task_struct *task, unsigned long *sp)
9595
}
9696
}
9797

98-
void
99-
dump_stack (void)
100-
{
101-
show_stack(NULL, NULL);
102-
}
103-
104-
EXPORT_SYMBOL(dump_stack);
105-
10698
void
10799
show_regs (struct pt_regs *regs)
108100
{

‎arch/m32r/kernel/traps.c

-9
Original file line numberDiff line numberDiff line change
@@ -167,15 +167,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
167167
show_trace(task, sp);
168168
}
169169

170-
void dump_stack(void)
171-
{
172-
unsigned long stack;
173-
174-
show_trace(current, &stack);
175-
}
176-
177-
EXPORT_SYMBOL(dump_stack);
178-
179170
static void show_registers(struct pt_regs *regs)
180171
{
181172
int i = 0;

‎arch/m68k/kernel/traps.c

-12
Original file line numberDiff line numberDiff line change
@@ -991,18 +991,6 @@ void show_stack(struct task_struct *task, unsigned long *stack)
991991
show_trace(stack);
992992
}
993993

994-
/*
995-
* The architecture-independent backtrace generator
996-
*/
997-
void dump_stack(void)
998-
{
999-
unsigned long stack;
1000-
1001-
show_trace(&stack);
1002-
}
1003-
1004-
EXPORT_SYMBOL(dump_stack);
1005-
1006994
/*
1007995
* The vector number returned in the frame pointer may also contain
1008996
* the "fs" (Fault Status) bits on ColdFire. These are in the bottom

‎arch/metag/kernel/traps.c

-6
Original file line numberDiff line numberDiff line change
@@ -987,9 +987,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
987987

988988
show_trace(tsk, sp, NULL);
989989
}
990-
991-
void dump_stack(void)
992-
{
993-
show_stack(NULL, NULL);
994-
}
995-
EXPORT_SYMBOL(dump_stack);

‎arch/microblaze/kernel/traps.c

-6
Original file line numberDiff line numberDiff line change
@@ -75,9 +75,3 @@ void show_stack(struct task_struct *task, unsigned long *sp)
7575

7676
debug_show_held_locks(task);
7777
}
78-
79-
void dump_stack(void)
80-
{
81-
show_stack(NULL, NULL);
82-
}
83-
EXPORT_SYMBOL(dump_stack);

‎arch/mips/kernel/traps.c

-13
Original file line numberDiff line numberDiff line change
@@ -206,19 +206,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
206206
show_stacktrace(task, &regs);
207207
}
208208

209-
/*
210-
* The architecture-independent dump_stack generator
211-
*/
212-
void dump_stack(void)
213-
{
214-
struct pt_regs regs;
215-
216-
prepare_frametrace(&regs);
217-
show_backtrace(current, &regs);
218-
}
219-
220-
EXPORT_SYMBOL(dump_stack);
221-
222209
static void show_code(unsigned int __user *pc)
223210
{
224211
long i;

‎arch/mn10300/kernel/traps.c

-11
Original file line numberDiff line numberDiff line change
@@ -293,17 +293,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
293293
show_trace(sp);
294294
}
295295

296-
/*
297-
* the architecture-independent dump_stack generator
298-
*/
299-
void dump_stack(void)
300-
{
301-
unsigned long stack;
302-
303-
show_stack(current, &stack);
304-
}
305-
EXPORT_SYMBOL(dump_stack);
306-
307296
/*
308297
* dump the register file in the specified exception frame
309298
*/

‎arch/openrisc/kernel/traps.c

-11
Original file line numberDiff line numberDiff line change
@@ -105,17 +105,6 @@ void show_trace_task(struct task_struct *tsk)
105105
*/
106106
}
107107

108-
/*
109-
* The architecture-independent backtrace generator
110-
*/
111-
void dump_stack(void)
112-
{
113-
unsigned long stack;
114-
115-
show_stack(current, &stack);
116-
}
117-
EXPORT_SYMBOL(dump_stack);
118-
119108
void show_registers(struct pt_regs *regs)
120109
{
121110
int i;

‎arch/parisc/kernel/traps.c

-8
Original file line numberDiff line numberDiff line change
@@ -158,14 +158,6 @@ void show_regs(struct pt_regs *regs)
158158
}
159159
}
160160

161-
162-
void dump_stack(void)
163-
{
164-
show_stack(NULL, NULL);
165-
}
166-
167-
EXPORT_SYMBOL(dump_stack);
168-
169161
static void do_show_stack(struct unwind_frame_info *info)
170162
{
171163
int i = 1;

‎arch/powerpc/kernel/process.c

-6
Original file line numberDiff line numberDiff line change
@@ -1362,12 +1362,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
13621362
} while (count++ < kstack_depth_to_print);
13631363
}
13641364

1365-
void dump_stack(void)
1366-
{
1367-
show_stack(current, NULL);
1368-
}
1369-
EXPORT_SYMBOL(dump_stack);
1370-
13711365
#ifdef CONFIG_PPC64
13721366
/* Called with hard IRQs off */
13731367
void __ppc64_runlatch_on(void)

‎arch/s390/kernel/dumpstack.c

-17
Original file line numberDiff line numberDiff line change
@@ -129,23 +129,6 @@ static void show_last_breaking_event(struct pt_regs *regs)
129129
#endif
130130
}
131131

132-
/*
133-
* The architecture-independent dump_stack generator
134-
*/
135-
void dump_stack(void)
136-
{
137-
printk("CPU: %d %s %s %.*s\n",
138-
task_thread_info(current)->cpu, print_tainted(),
139-
init_utsname()->release,
140-
(int)strcspn(init_utsname()->version, " "),
141-
init_utsname()->version);
142-
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
143-
current->comm, current->pid, current,
144-
(void *) current->thread.ksp);
145-
show_stack(NULL, NULL);
146-
}
147-
EXPORT_SYMBOL(dump_stack);
148-
149132
static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
150133
{
151134
return (regs->psw.mask & bits) / ((~bits + 1) & bits);

‎arch/score/kernel/traps.c

-10
Original file line numberDiff line numberDiff line change
@@ -149,16 +149,6 @@ static void show_registers(struct pt_regs *regs)
149149
printk(KERN_NOTICE "\n");
150150
}
151151

152-
/*
153-
* The architecture-independent dump_stack generator
154-
*/
155-
void dump_stack(void)
156-
{
157-
show_stack(current_thread_info()->task,
158-
(long *) get_irq_regs()->regs[0]);
159-
}
160-
EXPORT_SYMBOL(dump_stack);
161-
162152
void __die(const char *str, struct pt_regs *regs, const char *file,
163153
const char *func, unsigned long line)
164154
{

‎arch/sh/kernel/dumpstack.c

-6
Original file line numberDiff line numberDiff line change
@@ -158,9 +158,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
158158
(unsigned long)task_stack_page(tsk));
159159
show_trace(tsk, sp, NULL);
160160
}
161-
162-
void dump_stack(void)
163-
{
164-
show_stack(NULL, NULL);
165-
}
166-
EXPORT_SYMBOL(dump_stack);

‎arch/sparc/kernel/process_32.c

-7
Original file line numberDiff line numberDiff line change
@@ -164,13 +164,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
164164
printk("\n");
165165
}
166166

167-
void dump_stack(void)
168-
{
169-
show_stack(current, NULL);
170-
}
171-
172-
EXPORT_SYMBOL(dump_stack);
173-
174167
/*
175168
* Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
176169
*/

‎arch/sparc/kernel/traps_64.c

-7
Original file line numberDiff line numberDiff line change
@@ -2350,13 +2350,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
23502350
} while (++count < 16);
23512351
}
23522352

2353-
void dump_stack(void)
2354-
{
2355-
show_stack(current, NULL);
2356-
}
2357-
2358-
EXPORT_SYMBOL(dump_stack);
2359-
23602353
static inline struct reg_window *kernel_stack_up(struct reg_window *rw)
23612354
{
23622355
unsigned long fp = rw->ins[6];

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