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authorDavid S. Miller <davem@davemloft.net>2008-08-12 02:03:49 -0700
committerDavid S. Miller <davem@davemloft.net>2008-08-12 02:03:49 -0700
commitc7498081a6f5d96c9f3243b6b5e020352903bfd2 (patch)
treef23d27a2c973d0b0542f84cdd0b39be5e4ba406d
parentc6ed413ddcfb66e9d3e1318060271391c7659dd3 (diff)
sparc64: Fix recursion in stack overflow detection handling.
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>
-rw-r--r--arch/sparc64/lib/mcount.S17
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S
index 7735a7a6053..734caf0cec0 100644
--- a/arch/sparc64/lib/mcount.S
+++ b/arch/sparc64/lib/mcount.S
@@ -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