linux_dsm_epyc7002/arch/x86/include/asm/unwind.h
Josh Poimboeuf b02fcf9ba1 x86/unwinder: Handle stack overflows more gracefully
There are at least two unwinder bugs hindering the debugging of
stack-overflow crashes:

- It doesn't deal gracefully with the case where the stack overflows and
  the stack pointer itself isn't on a valid stack but the
  to-be-dereferenced data *is*.

- The ORC oops dump code doesn't know how to print partial pt_regs, for the
  case where if we get an interrupt/exception in *early* entry code
  before the full pt_regs have been saved.

Fix both issues.

http://lkml.kernel.org/r/20171126024031.uxi4numpbjm5rlbr@treble

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bpetkov@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150605.071425003@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-17 13:59:52 +01:00

112 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_UNWIND_H
#define _ASM_X86_UNWIND_H
#include <linux/sched.h>
#include <linux/ftrace.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
#define IRET_FRAME_OFFSET (offsetof(struct pt_regs, ip))
#define IRET_FRAME_SIZE (sizeof(struct pt_regs) - IRET_FRAME_OFFSET)
struct unwind_state {
struct stack_info stack_info;
unsigned long stack_mask;
struct task_struct *task;
int graph_idx;
bool error;
#if defined(CONFIG_UNWINDER_ORC)
bool signal, full_regs;
unsigned long sp, bp, ip;
struct pt_regs *regs;
#elif defined(CONFIG_UNWINDER_FRAME_POINTER)
bool got_irq;
unsigned long *bp, *orig_sp, ip;
struct pt_regs *regs;
#else
unsigned long *sp;
#endif
};
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame);
bool unwind_next_frame(struct unwind_state *state);
unsigned long unwind_get_return_address(struct unwind_state *state);
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state);
static inline bool unwind_done(struct unwind_state *state)
{
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
static inline bool unwind_error(struct unwind_state *state)
{
return state->error;
}
static inline
void unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
first_frame = first_frame ? : get_stack_pointer(task, regs);
__unwind_start(state, task, regs, first_frame);
}
#if defined(CONFIG_UNWINDER_ORC) || defined(CONFIG_UNWINDER_FRAME_POINTER)
/*
* WARNING: The entire pt_regs may not be safe to dereference. In some cases,
* only the iret frame registers are accessible. Use with caution!
*/
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
if (unwind_done(state))
return NULL;
return state->regs;
}
#else
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
return NULL;
}
#endif
#ifdef CONFIG_UNWINDER_ORC
void unwind_init(void);
void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
void *orc, size_t orc_size);
#else
static inline void unwind_init(void) {}
static inline
void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
void *orc, size_t orc_size) {}
#endif
/*
* This disables KASAN checking when reading a value from another task's stack,
* since the other task could be running on another CPU and could have poisoned
* the stack in the meantime.
*/
#define READ_ONCE_TASK_STACK(task, x) \
({ \
unsigned long val; \
if (task == current) \
val = READ_ONCE(x); \
else \
val = READ_ONCE_NOCHECK(x); \
val; \
})
static inline bool task_on_another_cpu(struct task_struct *task)
{
#ifdef CONFIG_SMP
return task != current && task->on_cpu;
#else
return false;
#endif
}
#endif /* _ASM_X86_UNWIND_H */