From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@ziepe.ca>, Joel Granados <j.granados@samsung.com>
Cc: baolu.lu@linux.intel.com, Kevin Tian <kevin.tian@intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Nicolin Chen <nicolinc@nvidia.com>, Yi Liu <yi.l.liu@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
iommu@lists.linux.dev, linux-kselftest@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/6] iommufd: Deliver fault messages to user space
Date: Fri, 8 Dec 2023 13:47:35 +0800 [thread overview]
Message-ID: <c72184d8-693d-43ce-aed9-00a8fc684137@linux.intel.com> (raw)
In-Reply-To: <20231207171742.GU1489931@ziepe.ca>
On 12/8/23 1:17 AM, Jason Gunthorpe wrote:
> On Thu, Dec 07, 2023 at 05:34:10PM +0100, Joel Granados wrote:
>>> @@ -58,6 +255,8 @@ static void hw_pagetable_fault_free(struct hw_pgtable_fault *fault)
>>> WARN_ON(!list_empty(&fault->deliver));
>>> WARN_ON(!list_empty(&fault->response));
>>>
>>> + fput(fault->fault_file);
>>> + put_unused_fd(fault->fault_fd);
>> I have resolved this in a naive way by just not calling the
>> put_unused_fd function.
> That is correct.
>
> put_unused_fd() should only be called on error paths prior to the
> syscall return.
>
> The design of a FD must follow this pattern
>
> syscall():
> fdno = get_unused_fd_flags(O_CLOEXEC);
> filep = [..]
>
> // syscall MUST succeed after this statement:
> fd_install(fdno, filep);
> return 0;
>
> err:
> put_unused_fd(fdno)
> return -ERRNO
Yes. Agreed.
>
> Also the refcounting looks a little strange, the filep reference is
> consumed by fd_install, so what is that fput pairing with in fault_free?
fput() pairs with get_unused_fd_flags()? fd_install() does not seem to
increase any reference.
Best regards,
baolu
next prev parent reply other threads:[~2023-12-08 5:52 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-26 2:49 [PATCH v2 0/6] IOMMUFD: Deliver IO page faults to user space Lu Baolu
2023-10-26 2:49 ` [PATCH v2 1/6] iommu: Add iommu page fault cookie helpers Lu Baolu
2023-12-01 14:38 ` Jason Gunthorpe
2023-12-08 6:24 ` Baolu Lu
2023-10-26 2:49 ` [PATCH v2 2/6] iommufd: Add iommu page fault uapi data Lu Baolu
2023-12-01 15:14 ` Jason Gunthorpe
2023-12-08 6:35 ` Baolu Lu
2023-10-26 2:49 ` [PATCH v2 3/6] iommufd: Initializing and releasing IO page fault data Lu Baolu
[not found] ` <CGME20231212131010eucas1p104d069ac6d6c97fce4987caa62c996ee@eucas1p1.samsung.com>
2023-12-12 13:10 ` Joel Granados
2023-12-12 14:12 ` Jason Gunthorpe
2023-12-13 2:04 ` Baolu Lu
2023-12-13 2:15 ` Tian, Kevin
2023-12-13 13:19 ` Jason Gunthorpe
2023-10-26 2:49 ` [PATCH v2 4/6] iommufd: Deliver fault messages to user space Lu Baolu
2023-12-01 15:24 ` Jason Gunthorpe
2023-12-08 11:43 ` Baolu Lu
[not found] ` <CGME20231207163412eucas1p2fa912b4923031804c27c764e5c8d67e7@eucas1p2.samsung.com>
2023-12-07 16:34 ` Joel Granados
2023-12-07 17:17 ` Jason Gunthorpe
2023-12-08 5:47 ` Baolu Lu [this message]
2023-12-08 13:41 ` Jason Gunthorpe
2024-01-12 17:46 ` Shameerali Kolothum Thodi
2024-01-15 16:47 ` Jason Gunthorpe
2024-01-15 17:44 ` Shameerali Kolothum Thodi
2024-01-15 17:58 ` Jason Gunthorpe
2023-10-26 2:49 ` [PATCH v2 5/6] iommufd/selftest: Add IOMMU_TEST_OP_TRIGGER_IOPF test support Lu Baolu
2023-10-26 2:49 ` [PATCH v2 6/6] iommufd/selftest: Add coverage for IOMMU_TEST_OP_TRIGGER_IOPF Lu Baolu
2023-11-02 12:47 ` [PATCH v2 0/6] IOMMUFD: Deliver IO page faults to user space Jason Gunthorpe
2023-11-02 12:47 ` Jason Gunthorpe
2023-11-07 8:35 ` Tian, Kevin
2023-11-07 8:35 ` Tian, Kevin
2023-11-07 17:54 ` Jason Gunthorpe
2023-11-07 17:54 ` Jason Gunthorpe
2023-11-08 8:53 ` Tian, Kevin
2023-11-08 17:39 ` Jason Gunthorpe
[not found] ` <c774e157-9b47-4fb8-80dd-37441c69b43d@linux.intel.com>
2023-11-15 13:58 ` Jason Gunthorpe
2023-11-16 1:42 ` Liu, Jing2
2023-11-21 0:14 ` Jason Gunthorpe
2023-11-29 9:08 ` Shameerali Kolothum Thodi
2023-11-30 3:44 ` Baolu Lu
2023-12-01 14:24 ` Jason Gunthorpe
2023-12-08 5:57 ` Baolu Lu
2023-12-08 13:43 ` Jason Gunthorpe
[not found] ` <CGME20231204150747eucas1p2365e92a7ac33ba99b801d7c800acaf6a@eucas1p2.samsung.com>
2023-12-04 15:07 ` Joel Granados
2023-12-04 15:32 ` Jason Gunthorpe
2023-12-08 5:10 ` Baolu Lu
[not found] ` <CGME20240112215609eucas1p1eedeeee8e1cca2c935b41816a50f56f6@eucas1p1.samsung.com>
2024-01-12 21:56 ` Joel Granados
2024-01-14 13:13 ` Baolu Lu
2024-01-14 17:18 ` Joel Granados
2024-01-15 1:25 ` Baolu Lu
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