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csky: patch_text: Fixup last cpu should be master

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commit 8c4d16471e upstream.

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: 33e53ae1ce ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Guo Ren
2022-04-06 22:28:43 +08:00
committed by Greg Kroah-Hartman
parent 31dca00d0c
commit df7f0f8be3
1 changed files with 1 additions and 1 deletions
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2
arch/csky/kernel/probes/kprobes.c
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@@ -28,7 +28,7 @@ static int __kprobes patch_text_cb(void *priv)
struct csky_insn_patch *param = priv; struct csky_insn_patch *param = priv;
unsigned int addr = (unsigned int)param->addr; unsigned int addr = (unsigned int)param->addr;
if (atomic_inc_return(&param->cpu_count) == 1) { if (atomic_inc_return(&param->cpu_count) == num_online_cpus()) {
*(u16 *) addr = cpu_to_le16(param->opcode); *(u16 *) addr = cpu_to_le16(param->opcode);
dcache_wb_range(addr, addr + 2); dcache_wb_range(addr, addr + 2);
atomic_inc(&param->cpu_count); atomic_inc(&param->cpu_count);