[PARISC] Fix show_stack() when we can't kmalloc (9f15c826) · Commits · 戴 / test

show_stack() was calling kzalloc() to allocate a struct pt_regs. This meant that *really* early stack dumps would cause a null pointer dereference. x86_64 allocates its pt_regs on the stack, so do the same. Kyle actually committed this exact patch to CVS on Wed Jul 26 14:32:39 2006 UTC, and never moved it across to git. Bad Kyle. Signed-off-by:

Matthew Wilcox <matthew@wil.cx> Signed-off-by:

Kyle McMartin <kyle@parisc-linux.org>

arch/parisc/kernel/traps.c

+10 −9

Original line number	Diff line number	Diff line
		@@ -187,18 +187,19 @@ void show_stack(struct task_struct task, unsigned long s)

		if (!task) {
		unsigned long sp;
		struct pt_regs *r;

		HERE:
		asm volatile ("copy %%r30, %0" : "=r"(sp));
		r = kzalloc(sizeof(struct pt_regs), GFP_KERNEL);
		if (!r)
		return;
		r->iaoq[0] = (unsigned long)&&HERE;
		r->gr[2] = (unsigned long)__builtin_return_address(0);
		r->gr[30] = sp;
		unwind_frame_init(&info, current, r);
		kfree(r);
		{
		struct pt_regs r;

		memset(&r, 0, sizeof(struct pt_regs));
		r.iaoq[0] = (unsigned long)&&HERE;
		r.gr[2] = (unsigned long)__builtin_return_address(0);
		r.gr[30] = sp;

		unwind_frame_init(&info, current, &r);
		}
		} else {
		unwind_frame_init_from_blocked_task(&info, task);
		}

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