sparc32: Fix unaligned stack handling on trap return. (9088333e) · Commits · 戴 / test

When the rett stack checking code sees the stack is unaligned (in both the sun4c and srmmu cases) it jumps to the window fault-in path. But that just tries to page the stack pages in, it doesn't do anything special if the stack is misaligned. Therefore we essentially just loop forever in the trap return path. Fix this by emitting a SIGILL in the stack fault-in code if the stack is mis-aligned. Reported-by:

Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:

David S. Miller <davem@davemloft.net>

arch/sparc/mm/fault_32.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -539,6 +539,12 @@ do_sigbus:
		__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
		}

		static void check_stack_aligned(unsigned long sp)
		{
		if (sp & 0x7UL)
		force_sig(SIGILL, current);
		}

		void window_overflow_fault(void)
		{
		unsigned long sp;
		@@ -547,6 +553,8 @@ void window_overflow_fault(void)
		if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 1);
		force_user_fault(sp, 1);

		check_stack_aligned(sp);
		}

		void window_underflow_fault(unsigned long sp)
		@@ -554,6 +562,8 @@ void window_underflow_fault(unsigned long sp)
		if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 0);
		force_user_fault(sp, 0);

		check_stack_aligned(sp);
		}

		void window_ret_fault(struct pt_regs *regs)
		@@ -564,4 +574,6 @@ void window_ret_fault(struct pt_regs *regs)
		if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 0);
		force_user_fault(sp, 0);

		check_stack_aligned(sp);
		}

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