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authorDavid S. Miller <davem@davemloft.net>2008-08-12 13:03:49 +0400
committerDavid S. Miller <davem@davemloft.net>2008-08-12 13:03:49 +0400
commitc7498081a6f5d96c9f3243b6b5e020352903bfd2 (patch)
treef23d27a2c973d0b0542f84cdd0b39be5e4ba406d /arch/sparc64/lib
parentc6ed413ddcfb66e9d3e1318060271391c7659dd3 (diff)
downloadlinux-c7498081a6f5d96c9f3243b6b5e020352903bfd2.tar.xz
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>
Diffstat (limited to 'arch/sparc64/lib')
-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 7735a7a60533..734caf0cec09 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