From 716386e397fabbbf9915d49f8bc79673fd2831bb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Wed, 20 May 2020 15:05:38 +0100 Subject: [PATCH] cpus-common: ensure auto-assigned cpu_indexes don't clash MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Basing the cpu_index on the number of currently allocated vCPUs fails when vCPUs aren't removed in a LIFO manner. This is especially true when we are allocating a cpu_index for each guest thread in linux-user where there is no ordering constraint on their allocation and de-allocation. [I've dropped the assert which is there to guard against out-of-order removal as this should probably be caught higher up the stack. Maybe we could just ifdef CONFIG_SOFTTMU it?] Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Acked-by: Igor Mammedow Cc: Nikolay Igotti Cc: Paolo Bonzini Cc: Eduardo Habkost Message-Id: <20200520140541.30256-13-alex.bennee@linaro.org> --- cpus-common.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/cpus-common.c b/cpus-common.c index 55d5df8923..70a9d12981 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -61,13 +61,15 @@ static bool cpu_index_auto_assigned; static int cpu_get_free_index(void) { CPUState *some_cpu; - int cpu_index = 0; + int max_cpu_index = 0; cpu_index_auto_assigned = true; CPU_FOREACH(some_cpu) { - cpu_index++; + if (some_cpu->cpu_index >= max_cpu_index) { + max_cpu_index = some_cpu->cpu_index + 1; + } } - return cpu_index; + return max_cpu_index; } void cpu_list_add(CPUState *cpu) @@ -90,8 +92,6 @@ void cpu_list_remove(CPUState *cpu) return; } - assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus))); - QTAILQ_REMOVE_RCU(&cpus, cpu, node); cpu->cpu_index = UNASSIGNED_CPU_INDEX; }