From 8ec1442953c66a1d8462cccd8c20b7ba561f5915 Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Wed, 6 Apr 2022 22:16:49 +0800 Subject: riscv: patch_text: Fixup last cpu should be master 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. Signed-off-by: Guo Ren Signed-off-by: Guo Ren Acked-by: Palmer Dabbelt Reviewed-by: Masami Hiramatsu Fixes: 043cb41a85de ("riscv: introduce interfaces to patch kernel code") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/patch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 0b552873a577..765004b60513 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -104,7 +104,7 @@ static int patch_text_cb(void *data) struct patch_insn *patch = data; int ret = 0; - if (atomic_inc_return(&patch->cpu_count) == 1) { + if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { ret = patch_text_nosync(patch->addr, &patch->insn, GET_INSN_LENGTH(patch->insn)); -- cgit v1.2.3