On the sh architecture, kprobes and gdb/gdbserver use different
breakpoint opcodes. Without this fix, kprobes doesn't recognize
the gdb traps, and the resulting NOTIFY_STOP prevents ptrace and gdb
from being notified. The result is that if kprobes is configured,
a gdb-traced process hangs when its gdb breakpoint is hit.
Signed-off-by: Jim Keniston <[email protected]>
Signed-off-by: Reza Arbab <[email protected]>
Reported-by: Vijay Kumar <[email protected]>
Tested-by: Vijay Kumar <[email protected]>
---
arch/sh/include/asm/kprobes.h | 2 ++
arch/sh/kernel/kprobes.c | 5 ++++-
2 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/sh/include/asm/kprobes.h b/arch/sh/include/asm/kprobes.h
index 134f398..f22a3cb 100644
--- a/arch/sh/include/asm/kprobes.h
+++ b/arch/sh/include/asm/kprobes.h
@@ -8,6 +8,8 @@
typedef insn_size_t kprobe_opcode_t;
#define BREAKPOINT_INSTRUCTION 0xc33a
+#define GDB_BREAKPOINT_INSTRUCTION 0xc3c3
+#define GDBSERVER_BREAKPOINT_INSTRUCTION 0xc320
#define MAX_INSN_SIZE 16
#define MAX_STACK_SIZE 64
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 83acbf3..bcaa072 100644
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -260,7 +260,10 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
p = get_kprobe(addr);
if (!p) {
/* Not one of ours: let kernel handle it */
- if (*(kprobe_opcode_t *)addr != BREAKPOINT_INSTRUCTION) {
+ kprobe_opcode_t opcode = *(kprobe_opcode_t *)addr;
+ if (opcode != BREAKPOINT_INSTRUCTION &&
+ opcode != GDB_BREAKPOINT_INSTRUCTION &&
+ opcode != GDBSERVER_BREAKPOINT_INSTRUCTION) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed