sparc64: Fix recursion in stack overflow detection handling. (c7498081) · Commits · 戴 / test

The calls down into prom_printf() when we detect an overflowed stack can recurse again since the overflow stack will be "below" the current kernel stack limit. Prevent this by just returning straight if we are on the stack overflow safe stack already. Signed-off-by:

David S. Miller <davem@davemloft.net>

arch/sparc64/lib/mcount.S

+14 −3

Original line number	Diff line number	Diff line
		@@ -48,12 +48,23 @@ mcount:
		sub %g3, STACK_BIAS, %g3
		cmp %sp, %g3
		bg,pt %xcc, 1f
		sethi %hi(panicstring), %g3
		nop
		/* If we are already on ovstack, don't hop onto it
		* again, we are already trying to output the stack overflow
		* message.
		*/
		sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
		or %g7, %lo(ovstack), %g7
		add %g7, OVSTACKSIZE, %g7
		add %g7, OVSTACKSIZE, %g3
		sub %g3, STACK_BIAS + 192, %g3
		sub %g7, STACK_BIAS, %g7
		mov %g7, %sp
		cmp %sp, %g7
		blu,pn %xcc, 2f
		cmp %sp, %g3
		bleu,pn %xcc, 1f
		nop
		2: mov %g3, %sp
		sethi %hi(panicstring), %g3
		call prom_printf
		or %g3, %lo(panicstring), %o0
		call prom_halt

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