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Commit 1bca09f7 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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s390/dumpstack: fix call chain walking 

dumpstack() did not always print a sane callchain when being called.
The reason is that show_trace() accessed register 15 directly to get
the current stack pointer and passed that pointer to __show_trace()
which expects a valid stack frame pointer as argument.
However due to tail call optimization the stack frame may not exist
anymore when __show_trace() gets called and therefore an invalid
stack frame pointer gets passed.
To prevent that disable tail call optimization for call chain walking
functions.
So move all the show_* functions to a dumpstack.c file like other
architectures have it already and add a -fno-optimize-sibling-calls
compile flag to both dumpstack.c and stacktrace.c to prevent tail
call optimization.

Fixes callchains that looked e.g. like this:

[   12.868258] Call Trace:
[   12.868262] ([<0000000000008000>] 0x8000)
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 2b55732a
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Showing with 253 additions and 250 deletions
arch/s390/kernel/Makefile
View file @ 1bca09f7
...@@ -13,6 +13,14 @@ endif ...@@ -13,6 +13,14 @@ endif
# #
CFLAGS_smp.o := -Wno-nonnull CFLAGS_smp.o := -Wno-nonnull
#
# Disable tailcall optimizations for stack / callchain walking functions
# since this might generate broken code when accessing register 15 and
# passing its content to other functions.
#
CFLAGS_stacktrace.o += -fno-optimize-sibling-calls
CFLAGS_dumpstack.o += -fno-optimize-sibling-calls
# #
# Pass UTS_MACHINE for user_regset definition # Pass UTS_MACHINE for user_regset definition
# #
...@@ -20,10 +28,11 @@ CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"' ...@@ -20,10 +28,11 @@ CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'
CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w
obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o \ obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o
processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o \ obj-y += processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
debug.o irq.o ipl.o dis.o diag.o mem_detect.o sclp.o vdso.o \ obj-y += debug.o irq.o ipl.o dis.o diag.o mem_detect.o sclp.o vdso.o
sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o obj-y += sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
obj-y += dumpstack.o
obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o) obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o)
obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o) obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
......
arch/s390/kernel/dumpstack.c 0 → 100644
View file @ 1bca09f7
/*
* Stack dumping functions
*
* Copyright IBM Corp. 1999, 2013
*/
#include <linux/kallsyms.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/utsname.h>
#include <linux/export.h>
#include <linux/kdebug.h>
#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <asm/processor.h>
#include <asm/debug.h>
#include <asm/ipl.h>
#ifndef CONFIG_64BIT
#define LONG "%08lx "
#define FOURLONG "%08lx %08lx %08lx %08lx\n"
static int kstack_depth_to_print = 12;
#else /* CONFIG_64BIT */
#define LONG "%016lx "
#define FOURLONG "%016lx %016lx %016lx %016lx\n"
static int kstack_depth_to_print = 20;
#endif /* CONFIG_64BIT */
/*
* For show_trace we have tree different stack to consider:
* - the panic stack which is used if the kernel stack has overflown
* - the asynchronous interrupt stack (cpu related)
* - the synchronous kernel stack (process related)
* The stack trace can start at any of the three stack and can potentially
* touch all of them. The order is: panic stack, async stack, sync stack.
*/
static unsigned long
__show_trace(unsigned long sp, unsigned long low, unsigned long high)
{
struct stack_frame *sf;
struct pt_regs *regs;
while (1) {
sp = sp & PSW_ADDR_INSN;
if (sp < low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
/* Follow the backchain. */
while (1) {
low = sp;
sp = sf->back_chain & PSW_ADDR_INSN;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long) (sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *) sp;
printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
low = sp;
sp = regs->gprs[15];
}
}
static void show_trace(struct task_struct *task, unsigned long *stack)
{
register unsigned long __r15 asm ("15");
unsigned long sp;
sp = (unsigned long) stack;
if (!sp)
sp = task ? task->thread.ksp : __r15;
printk("Call Trace:\n");
#ifdef CONFIG_CHECK_STACK
sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
S390_lowcore.panic_stack);
#endif
sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
S390_lowcore.async_stack);
if (task)
__show_trace(sp, (unsigned long) task_stack_page(task),
(unsigned long) task_stack_page(task) + THREAD_SIZE);
else
__show_trace(sp, S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE);
if (!task)
task = current;
debug_show_held_locks(task);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
register unsigned long *__r15 asm ("15");
unsigned long *stack;
int i;
if (!sp)
stack = task ? (unsigned long *) task->thread.ksp : __r15;
else
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
break;
if ((i * sizeof(long) % 32) == 0)
printk("%s ", i == 0 ? "" : "\n");
printk(LONG, *stack++);
}
printk("\n");
show_trace(task, sp);
}
static void show_last_breaking_event(struct pt_regs *regs)
{
#ifdef CONFIG_64BIT
printk("Last Breaking-Event-Address:\n");
printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
#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);
}
void show_registers(struct pt_regs *regs)
{
char *mode;
mode = user_mode(regs) ? "User" : "Krnl";
printk("%s PSW : %p %p",
mode, (void *) regs->psw.mask,
(void *) regs->psw.addr);
print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
"P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
#ifdef CONFIG_64BIT
printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
#endif
printk("\n%s GPRS: " FOURLONG, mode,
regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
printk(" " FOURLONG,
regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
printk(" " FOURLONG,
regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
printk(" " FOURLONG,
regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
show_code(regs);
}
void show_regs(struct pt_regs *regs)
{
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_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!user_mode(regs))
show_trace(NULL, (unsigned long *) regs->gprs[15]);
show_last_breaking_event(regs);
}
static DEFINE_SPINLOCK(die_lock);
void die(struct pt_regs *regs, const char *str)
{
static int die_counter;
oops_enter();
lgr_info_log();
debug_stop_all();
console_verbose();
spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
print_modules();
show_regs(regs);
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception: panic_on_oops");
oops_exit();
do_exit(SIGSEGV);
}
arch/s390/kernel/traps.c
View file @ 1bca09f7
...@@ -12,49 +12,16 @@ ...@@ -12,49 +12,16 @@
* 'Traps.c' handles hardware traps and faults after we have saved some * 'Traps.c' handles hardware traps and faults after we have saved some
* state in 'asm.s'. * state in 'asm.s'.
*/ */
#include <linux/sched.h> #include <linux/kprobes.h>
#include <linux/kernel.h> #include <linux/kdebug.h>
#include <linux/string.h> #include <linux/module.h>
#include <linux/errno.h>
#include <linux/ptrace.h> #include <linux/ptrace.h>
#include <linux/timer.h> #include <linux/sched.h>
#include <linux/mm.h> #include <linux/mm.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/kdebug.h>
#include <linux/kallsyms.h>
#include <linux/reboot.h>
#include <linux/kprobes.h>
#include <linux/bug.h>
#include <linux/utsname.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/atomic.h>
#include <asm/mathemu.h>
#include <asm/cpcmd.h>
#include <asm/lowcore.h>
#include <asm/debug.h>
#include <asm/ipl.h>
#include "entry.h" #include "entry.h"
int show_unhandled_signals = 1; int show_unhandled_signals = 1;
#define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
#ifndef CONFIG_64BIT
#define LONG "%08lx "
#define FOURLONG "%08lx %08lx %08lx %08lx\n"
static int kstack_depth_to_print = 12;
#else /* CONFIG_64BIT */
#define LONG "%016lx "
#define FOURLONG "%016lx %016lx %016lx %016lx\n"
static int kstack_depth_to_print = 20;
#endif /* CONFIG_64BIT */
static inline void __user *get_trap_ip(struct pt_regs *regs) static inline void __user *get_trap_ip(struct pt_regs *regs)
{ {
#ifdef CONFIG_64BIT #ifdef CONFIG_64BIT
...@@ -72,215 +39,6 @@ static inline void __user *get_trap_ip(struct pt_regs *regs) ...@@ -72,215 +39,6 @@ static inline void __user *get_trap_ip(struct pt_regs *regs)
#endif #endif
} }
/*
* For show_trace we have tree different stack to consider:
* - the panic stack which is used if the kernel stack has overflown
* - the asynchronous interrupt stack (cpu related)
* - the synchronous kernel stack (process related)
* The stack trace can start at any of the three stack and can potentially
* touch all of them. The order is: panic stack, async stack, sync stack.
*/
static unsigned long
__show_trace(unsigned long sp, unsigned long low, unsigned long high)
{
struct stack_frame *sf;
struct pt_regs *regs;
while (1) {
sp = sp & PSW_ADDR_INSN;
if (sp < low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
/* Follow the backchain. */
while (1) {
low = sp;
sp = sf->back_chain & PSW_ADDR_INSN;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long) (sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *) sp;
printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
low = sp;
sp = regs->gprs[15];
}
}
static void show_trace(struct task_struct *task, unsigned long *stack)
{
register unsigned long __r15 asm ("15");
unsigned long sp;
sp = (unsigned long) stack;
if (!sp)
sp = task ? task->thread.ksp : __r15;
printk("Call Trace:\n");
#ifdef CONFIG_CHECK_STACK
sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
S390_lowcore.panic_stack);
#endif
sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
S390_lowcore.async_stack);
if (task)
__show_trace(sp, (unsigned long) task_stack_page(task),
(unsigned long) task_stack_page(task) + THREAD_SIZE);
else
__show_trace(sp, S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE);
if (!task)
task = current;
debug_show_held_locks(task);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
register unsigned long * __r15 asm ("15");
unsigned long *stack;
int i;
if (!sp)
stack = task ? (unsigned long *) task->thread.ksp : __r15;
else
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
break;
if ((i * sizeof(long) % 32) == 0)
printk("%s ", i == 0 ? "" : "\n");
printk(LONG, *stack++);
}
printk("\n");
show_trace(task, sp);
}
static void show_last_breaking_event(struct pt_regs *regs)
{
#ifdef CONFIG_64BIT
printk("Last Breaking-Event-Address:\n");
printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
#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);
}
void show_registers(struct pt_regs *regs)
{
char *mode;
mode = user_mode(regs) ? "User" : "Krnl";
printk("%s PSW : %p %p",
mode, (void *) regs->psw.mask,
(void *) regs->psw.addr);
print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
"P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
#ifdef CONFIG_64BIT
printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
#endif
printk("\n%s GPRS: " FOURLONG, mode,
regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
printk(" " FOURLONG,
regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
printk(" " FOURLONG,
regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
printk(" " FOURLONG,
regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
show_code(regs);
}
void show_regs(struct pt_regs *regs)
{
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_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!user_mode(regs))
show_trace(NULL, (unsigned long *) regs->gprs[15]);
show_last_breaking_event(regs);
}
static DEFINE_SPINLOCK(die_lock);
void die(struct pt_regs *regs, const char *str)
{
static int die_counter;
oops_enter();
lgr_info_log();
debug_stop_all();
console_verbose();
spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
print_modules();
show_regs(regs);
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception: panic_on_oops");
oops_exit();
do_exit(SIGSEGV);
}
static inline void report_user_fault(struct pt_regs *regs, int signr) static inline void report_user_fault(struct pt_regs *regs, int signr)
{ {
if ((task_pid_nr(current) > 1) && !show_unhandled_signals) if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
......
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