diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2017-01-09 21:00:24 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-12 11:28:28 +0300 |
| commit | 2c96b2fe9c57b4267c3f0a680d82d7cc52e1c447 (patch) | |
| tree | f2473ff9a7b87e0f5766120cf99db683b6280f6f /arch/x86 | |
| parent | 84936118bdf37bda513d4a361c38181a216427e0 (diff) | |
| download | linux-2c96b2fe9c57b4267c3f0a680d82d7cc52e1c447.tar.xz | |
x86/unwind: Include __schedule() in stack traces
In the following commit:
0100301bfdf5 ("sched/x86: Rewrite the switch_to() code")
... the layout of the 'inactive_task_frame' struct was designed to have
a frame pointer header embedded in it, so that the unwinder could use
the 'bp' and 'ret_addr' fields to report __schedule() on the stack (or
ret_from_fork() for newly forked tasks which haven't actually run yet).
Finish the job by changing get_frame_pointer() to return a pointer to
inactive_task_frame's 'bp' field rather than 'bp' itself. This allows
the unwinder to start one frame higher on the stack, so that it properly
reports __schedule().
Reported-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/598e9f7505ed0aba86e8b9590aa528c6c7ae8dcd.1483978430.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/stacktrace.h | 5 | ||||
| -rw-r--r-- | arch/x86/include/asm/switch_to.h | 10 |
2 files changed, 10 insertions, 5 deletions
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index 20ce3db20f24..2e41c50ddf47 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -52,16 +52,13 @@ static inline bool on_stack(struct stack_info *info, void *addr, size_t len) static inline unsigned long * get_frame_pointer(struct task_struct *task, struct pt_regs *regs) { - struct inactive_task_frame *frame; - if (regs) return (unsigned long *)regs->bp; if (task == current) return __builtin_frame_address(0); - frame = (struct inactive_task_frame *)task->thread.sp; - return (unsigned long *)READ_ONCE_NOCHECK(frame->bp); + return &((struct inactive_task_frame *)task->thread.sp)->bp; } #else static inline unsigned long * diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index 5cb436acd463..fcc5cd387fd1 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -36,7 +36,10 @@ static inline void prepare_switch_to(struct task_struct *prev, asmlinkage void ret_from_fork(void); -/* data that is pointed to by thread.sp */ +/* + * This is the structure pointed to by thread.sp for an inactive task. The + * order of the fields must match the code in __switch_to_asm(). + */ struct inactive_task_frame { #ifdef CONFIG_X86_64 unsigned long r15; @@ -48,6 +51,11 @@ struct inactive_task_frame { unsigned long di; #endif unsigned long bx; + + /* + * These two fields must be together. They form a stack frame header, + * needed by get_frame_pointer(). + */ unsigned long bp; unsigned long ret_addr; }; |