From d3065bf0a83e02032d0900566fa8605d8865073d Mon Sep 17 00:00:00 2001 From: Alejandro Vallejo Date: Mon, 17 Jul 2023 08:34:11 +0200 Subject: [PATCH] x86/microcode: Add missing unlock in microcode_update_helper() microcode_update_helper() may return early while holding cpu_add_remove_lock, hence preventing any writers from taking it again. Leave through the `put` label instead so it's properly released. Fixes: 5ed12565aa32 ("microcode: rendezvous CPUs in NMI handler and load ucode") Signed-off-by: Alejandro Vallejo Reviewed-by: Andrew Cooper master commit: b35b22acb887f682efe8385b3df165220bc84c86 master date: 2023-06-05 16:11:10 +0100 --- xen/arch/x86/cpu/microcode/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode/core.c index ad150e5963..cd942130f5 100644 --- a/xen/arch/x86/cpu/microcode/core.c +++ b/xen/arch/x86/cpu/microcode/core.c @@ -594,7 +594,8 @@ static long microcode_update_helper(void *data) printk(XENLOG_WARNING "CPU%u is expected to lead ucode loading (but got CPU%u)\n", nmi_cpu, cpumask_first(&cpu_online_map)); - return -EPERM; + ret = -EPERM; + goto put; } patch = parse_blob(buffer->buffer, buffer->len); -- 2.39.5