From: Guo Ren guoren@linux.alibaba.com
These patch_text implementations are using stop_machine_cpuslocked infrastructure with atomic cpu_count. The original idea: When the master CPU patch_text, the others should wait for it. But current implementation is using the first CPU as master, which couldn't guarantee the remaining CPUs are waiting. This patch changes the last CPU as the master to solve the potential risk.
Fixes: 33e53ae1ce41 ("csky: Add kprobes supported") Signed-off-by: Guo Ren guoren@linux.alibaba.com Signed-off-by: Guo Ren guoren@kernel.org Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Cc: stable@vger.kernel.org --- arch/csky/kernel/probes/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c index 42920f25e73c..34ba684d5962 100644 --- a/arch/csky/kernel/probes/kprobes.c +++ b/arch/csky/kernel/probes/kprobes.c @@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void *priv) struct csky_insn_patch *param = priv; unsigned int addr = (unsigned int)param->addr;
- if (atomic_inc_return(¶m->cpu_count) == 1) { + if (atomic_inc_return(¶m->cpu_count) == num_online_cpus()) { *(u16 *) addr = cpu_to_le16(param->opcode); dcache_wb_range(addr, addr + 2); atomic_inc(¶m->cpu_count);