From: Mike Christie <michael.christie@oracle.com>
To: Bodo Stroesser <bostroesser@gmail.com>,
linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] scsi: target: tcmu: Fix wrong uio handling causing big memory leak
Date: Tue, 12 Jan 2021 12:36:24 -0600 [thread overview]
Message-ID: <73dc2d01-6398-c1d1-df47-66034d184eec@oracle.com> (raw)
In-Reply-To: <20201218141534.9918-1-bostroesser@gmail.com>
On 12/18/20 8:15 AM, Bodo Stroesser wrote:
> tcmu calls uio_unregister_device from tcmu_destroy_device.
> After that uio will never call tcmu_release for this device.
> If userspace still had the uio device open and / or mmap'ed
> during uio_unregister_device, tcmu_release will not be called and
> udev->kref will never go down to 0.
>
I didn't get why the release function is not called if you call
uio_unregister_device while a device is open. Does the device_destroy call in
uio_unregister_device completely free the device or does it set some bits so
uio_release is not called later?
Do other drivers hit this? Should uio have refcounting so uio_release is called
when the last ref (from userspace open/close/mmap calls and from the kernel by
drivers like target_core_user) is done?
next prev parent reply other threads:[~2021-01-12 18:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-18 14:15 [PATCH] scsi: target: tcmu: Fix wrong uio handling causing big memory leak Bodo Stroesser
2021-01-11 18:22 ` Bodo Stroesser
2021-01-12 18:36 ` Mike Christie [this message]
2021-01-13 17:59 ` Bodo Stroesser
2021-01-13 21:04 ` Mike Christie
2021-01-14 16:50 ` Bodo Stroesser
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