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sched: Add wrapper for get_wchan() to keep task blocked
Having a stable wchan means the process must be blocked and for it to stay that way while performing stack unwinding. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm] Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64] Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org
This commit is contained in:
committed by
Peter Zijlstra
parent
bc9bbb8173
commit
42a20f86dc
@@ -511,7 +511,7 @@ static int __init frame_info_init(void)
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/*
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* Without schedule() frame info, result given by
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* thread_saved_pc() and get_wchan() are not reliable.
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* thread_saved_pc() and __get_wchan() are not reliable.
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*/
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if (schedule_mfi.pc_offset < 0)
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printk("Can't analyze schedule() prologue at %p\n", schedule);
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@@ -652,9 +652,9 @@ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
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#endif
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/*
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* get_wchan - a maintenance nightmare^W^Wpain in the ass ...
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* __get_wchan - a maintenance nightmare^W^Wpain in the ass ...
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*/
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unsigned long get_wchan(struct task_struct *task)
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unsigned long __get_wchan(struct task_struct *task)
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{
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unsigned long pc = 0;
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#ifdef CONFIG_KALLSYMS
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@@ -662,8 +662,6 @@ unsigned long get_wchan(struct task_struct *task)
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unsigned long ra = 0;
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#endif
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if (!task || task == current || task_is_running(task))
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goto out;
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if (!task_stack_page(task))
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goto out;
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