* [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails @ 2021-06-09 13:35 Xiyu Yang 2021-06-09 14:12 ` Robin Murphy 0 siblings, 1 reply; 3+ messages in thread From: Xiyu Yang @ 2021-06-09 13:35 UTC (permalink / raw) To: Will Deacon, Robin Murphy, Joerg Roedel, Nicolin Chen, Bjorn Andersson, Krishna Reddy, Jordan Crouse, Sai Prakash Ranjan, linux-arm-kernel, iommu, linux-kernel Cc: yuanxzhang, Xiyu Yang, Xin Tan arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the refcount of the "smmu" even though the return value is less than 0. The reference counting issue happens in some error handling paths of arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get() fails, the caller functions forget to decrease the refcount of "smmu" increased by arm_smmu_rpm_get(), causing a refcount leak. Fix this issue by calling arm_smmu_rpm_put() or jumping to the "rpm_put" label when arm_smmu_rpm_get() fails. Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> --- drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 6f72c4d208ca..177ee54c5534 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -840,7 +840,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) ret = arm_smmu_rpm_get(smmu); if (ret < 0) - return; + goto rpm_put; /* * Disable the context bank and free the page tables before freeing @@ -857,6 +857,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) free_io_pgtable_ops(smmu_domain->pgtbl_ops); __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); +rpm_put: arm_smmu_rpm_put(smmu); } @@ -1153,7 +1154,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) ret = arm_smmu_rpm_get(smmu); if (ret < 0) - return ret; + goto rpm_put; /* Ensure that the domain is finalised */ ret = arm_smmu_init_domain_context(domain, smmu, dev); @@ -1404,7 +1405,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) ret = arm_smmu_rpm_get(smmu); if (ret < 0) - goto out_cfg_free; + goto rpm_put; ret = arm_smmu_master_alloc_smes(dev); arm_smmu_rpm_put(smmu); @@ -1417,6 +1418,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) return &smmu->iommu; +rpm_put: + arm_smmu_rpm_put(smmu); out_cfg_free: kfree(cfg); out_free: @@ -1438,8 +1441,10 @@ static void arm_smmu_release_device(struct device *dev) smmu = cfg->smmu; ret = arm_smmu_rpm_get(smmu); - if (ret < 0) + if (ret < 0) { + arm_smmu_rpm_put(smmu); return; + } arm_smmu_master_free_smes(cfg, fwspec); -- 2.7.4 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails 2021-06-09 13:35 [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails Xiyu Yang @ 2021-06-09 14:12 ` Robin Murphy 2021-06-10 2:20 ` Xiyu Yang 0 siblings, 1 reply; 3+ messages in thread From: Robin Murphy @ 2021-06-09 14:12 UTC (permalink / raw) To: Xiyu Yang, Will Deacon, Joerg Roedel, Nicolin Chen, Bjorn Andersson, Krishna Reddy, Jordan Crouse, Sai Prakash Ranjan, linux-arm-kernel, iommu, linux-kernel Cc: yuanxzhang, Xin Tan On 2021-06-09 14:35, Xiyu Yang wrote: > arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the > refcount of the "smmu" even though the return value is less than 0. > > The reference counting issue happens in some error handling paths of > arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get() > fails, the caller functions forget to decrease the refcount of "smmu" > increased by arm_smmu_rpm_get(), causing a refcount leak. > > Fix this issue by calling arm_smmu_rpm_put() or jumping to the "rpm_put" > label when arm_smmu_rpm_get() fails. If only there was some kind of helper function which could encapsulate the correct expected behaviour in a single place... In fact with the new pm_runtime_resume_and_get() API I think these two patches boil down to a one-line change. Thanks, Robin. > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> > --- > drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c > index 6f72c4d208ca..177ee54c5534 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > @@ -840,7 +840,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > - return; > + goto rpm_put; > > /* > * Disable the context bank and free the page tables before freeing > @@ -857,6 +857,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > free_io_pgtable_ops(smmu_domain->pgtbl_ops); > __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); > > +rpm_put: > arm_smmu_rpm_put(smmu); > } > > @@ -1153,7 +1154,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) > > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > - return ret; > + goto rpm_put; > > /* Ensure that the domain is finalised */ > ret = arm_smmu_init_domain_context(domain, smmu, dev); > @@ -1404,7 +1405,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > - goto out_cfg_free; > + goto rpm_put; > > ret = arm_smmu_master_alloc_smes(dev); > arm_smmu_rpm_put(smmu); > @@ -1417,6 +1418,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > return &smmu->iommu; > > +rpm_put: > + arm_smmu_rpm_put(smmu); > out_cfg_free: > kfree(cfg); > out_free: > @@ -1438,8 +1441,10 @@ static void arm_smmu_release_device(struct device *dev) > smmu = cfg->smmu; > > ret = arm_smmu_rpm_get(smmu); > - if (ret < 0) > + if (ret < 0) { > + arm_smmu_rpm_put(smmu); > return; > + } > > arm_smmu_master_free_smes(cfg, fwspec); > > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Re: [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails 2021-06-09 14:12 ` Robin Murphy @ 2021-06-10 2:20 ` Xiyu Yang 0 siblings, 0 replies; 3+ messages in thread From: Xiyu Yang @ 2021-06-10 2:20 UTC (permalink / raw) To: Robin Murphy Cc: Will Deacon, Joerg Roedel, Nicolin Chen, Bjorn Andersson, Krishna Reddy, Jordan Crouse, Sai Prakash Ranjan, linux-arm-kernel, iommu, linux-kernel, yuanxzhang, Xin Tan Thanks for your advice, I'll send a v2 patch soon. > -----Original Messages----- > From: "Robin Murphy" <robin.murphy@arm.com> > Sent Time: 2021-06-09 22:12:11 (Wednesday) > To: "Xiyu Yang" <xiyuyang19@fudan.edu.cn>, "Will Deacon" <will@kernel.org>, "Joerg Roedel" <joro@8bytes.org>, "Nicolin Chen" <nicoleotsuka@gmail.com>, "Bjorn Andersson" <bjorn.andersson@linaro.org>, "Krishna Reddy" <vdumpa@nvidia.com>, "Jordan Crouse" <jordan@cosmicpenguin.net>, "Sai Prakash Ranjan" <saiprakash.ranjan@codeaurora.org>, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org > Cc: yuanxzhang@fudan.edu.cn, "Xin Tan" <tanxin.ctf@gmail.com> > Subject: Re: [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails > > On 2021-06-09 14:35, Xiyu Yang wrote: > > arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the > > refcount of the "smmu" even though the return value is less than 0. > > > > The reference counting issue happens in some error handling paths of > > arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get() > > fails, the caller functions forget to decrease the refcount of "smmu" > > increased by arm_smmu_rpm_get(), causing a refcount leak. > > > > Fix this issue by calling arm_smmu_rpm_put() or jumping to the "rpm_put" > > label when arm_smmu_rpm_get() fails. > > If only there was some kind of helper function which could encapsulate > the correct expected behaviour in a single place... > > In fact with the new pm_runtime_resume_and_get() API I think these two > patches boil down to a one-line change. > > Thanks, > Robin. > > > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> > > --- > > drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++---- > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > index 6f72c4d208ca..177ee54c5534 100644 > > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > @@ -840,7 +840,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - return; > > + goto rpm_put; > > > > /* > > * Disable the context bank and free the page tables before freeing > > @@ -857,6 +857,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > > free_io_pgtable_ops(smmu_domain->pgtbl_ops); > > __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); > > > > +rpm_put: > > arm_smmu_rpm_put(smmu); > > } > > > > @@ -1153,7 +1154,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - return ret; > > + goto rpm_put; > > > > /* Ensure that the domain is finalised */ > > ret = arm_smmu_init_domain_context(domain, smmu, dev); > > @@ -1404,7 +1405,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - goto out_cfg_free; > > + goto rpm_put; > > > > ret = arm_smmu_master_alloc_smes(dev); > > arm_smmu_rpm_put(smmu); > > @@ -1417,6 +1418,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > > > return &smmu->iommu; > > > > +rpm_put: > > + arm_smmu_rpm_put(smmu); > > out_cfg_free: > > kfree(cfg); > > out_free: > > @@ -1438,8 +1441,10 @@ static void arm_smmu_release_device(struct device *dev) > > smmu = cfg->smmu; > > > > ret = arm_smmu_rpm_get(smmu); > > - if (ret < 0) > > + if (ret < 0) { > > + arm_smmu_rpm_put(smmu); > > return; > > + } > > > > arm_smmu_master_free_smes(cfg, fwspec); > > > > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-06-10 2:21 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-06-09 13:35 [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails Xiyu Yang 2021-06-09 14:12 ` Robin Murphy 2021-06-10 2:20 ` Xiyu Yang
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