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authorbibo mao <bibo.mao@intel.com>2006-07-28 14:44:48 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-28 19:28:00 -0700
commita4045dff782a8692637c24a0222120082c887caa (patch)
tree67f4fe2bb6975bce2887c295752c7612896130f9
parent0e92da4acb763272c6060f0b14adc2377b627d07 (diff)
[PATCH] x86_64: Enlarge debug stack for nested kprobes
In x86_64 platform, INT1 and INT3 trap stack is IST stack called DEBUG_STACK, when INT1/INT3 trap happens, system will switch to DEBUG_STACK by hardware. Current DEBUG_STACK size is 4K, when int1/int3 trap happens, kernel will minus current DEBUG_STACK IST value by 4k. But if int3/int1 trap is nested, it will destroy other vector's IST stack. This patch modifies this, it sets DEBUG_STACK size as 8K and allows two level of nested int1/int3 trap. Kprobe DEBUG_STACK may be nested, because kprobe handler may be probed by other kprobes. Thanks jbeulich for pointing out error in the first patch. [AK: nested kprobes are pretty dubious. Hopefully one nest will be enough. This will cost 8K per CPU (4K more than before)] Signed-off-by: bibo, mao <bibo.mao@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/asm-x86_64/page.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h
index f7bf875aae4..10f346165ca 100644
--- a/include/asm-x86_64/page.h
+++ b/include/asm-x86_64/page.h
@@ -19,7 +19,7 @@
#define EXCEPTION_STACK_ORDER 0
#define EXCEPTION_STKSZ (PAGE_SIZE << EXCEPTION_STACK_ORDER)
-#define DEBUG_STACK_ORDER EXCEPTION_STACK_ORDER
+#define DEBUG_STACK_ORDER (EXCEPTION_STACK_ORDER + 1)
#define DEBUG_STKSZ (PAGE_SIZE << DEBUG_STACK_ORDER)
#define IRQSTACK_ORDER 2