From ae0c3751ab08d3fe039d48935e9ad2c46711b23b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 22 Jun 2011 15:32:48 +0100 Subject: [PATCH] ARM: 6975/1: pmu: reject duplicate PMU registrations Currently, the PMU reservation framework allows for multiple PMUs of the same type to register themselves. This can lead to a bug with the sequence: register_pmu(pmu1); reserve_pmu(pmu_type); register_pmu(pmu2); release_pmu(pmu1); Here, pmu1 cannot be released, and pmu2 cannot be reserved. This patch modifies register_pmu to reject registrations where a PMU is already present, preventing this problem. PMUs which can have multiple instances should not use the PMU reservation framework. Signed-off-by: Mark Rutland Acked-by: Jamie Iles Acked-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/pmu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm/kernel/pmu.c b/arch/arm/kernel/pmu.c index 87942b931c6..de6b1b0860c 100644 --- a/arch/arm/kernel/pmu.c +++ b/arch/arm/kernel/pmu.c @@ -34,13 +34,13 @@ static int __devinit pmu_register(struct platform_device *pdev, return -EINVAL; } - if (pmu_devices[type]) - pr_warning("registering new PMU device type %d overwrites " - "previous registration!\n", type); - else - pr_info("registered new PMU device of type %d\n", - type); + if (pmu_devices[type]) { + pr_warning("rejecting duplicate registration of PMU device " + "type %d.", type); + return -ENOSPC; + } + pr_info("registered new PMU device of type %d\n", type); pmu_devices[type] = pdev; return 0; } -- 2.39.2