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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-03-14 13:44:25 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-04-17 14:07:28 +0200
commit1bca09f7144450989e409c82ff0db83dddf489ac (patch)
treeb09d99a3ae8d557b0ba50759814ee422e82788ab /arch/s390/kernel
parent2b55732ad23fcc9eaec05acc21fd579ef8a9f38b (diff)
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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: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/Makefile17
-rw-r--r--arch/s390/kernel/dumpstack.c236
-rw-r--r--arch/s390/kernel/traps.c250
3 files changed, 253 insertions, 250 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 2ac311ef5c9b..1386fcaf4ef6 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -14,16 +14,25 @@ endif
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
#
CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'
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 \
- 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 \
- sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
+obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o
+obj-y += processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
+obj-y += debug.o irq.o ipl.o dis.o diag.o mem_detect.o sclp.o vdso.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),reipl64.o,reipl.o)
diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
new file mode 100644
index 000000000000..03dce39d01ee
--- /dev/null
+++ b/arch/s390/kernel/dumpstack.c
@@ -0,0 +1,236 @@
+/*
+ * 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);
+}
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 13dd63fba367..c5762324d9ee 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -12,49 +12,16 @@
* 'Traps.c' handles hardware traps and faults after we have saved some
* state in 'asm.s'.
*/
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/string.h>
-#include <linux/errno.h>
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
#include <linux/ptrace.h>
-#include <linux/timer.h>
+#include <linux/sched.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"
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)
{
#ifdef CONFIG_64BIT
@@ -72,215 +39,6 @@ static inline void __user *get_trap_ip(struct pt_regs *regs)
#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)
{
if ((task_pid_nr(current) > 1) && !show_unhandled_signals)