similar to: [PATCH 1/2] virtio: console: Fix crash when hot-unplugging a port and read is blocked

Hey Rusty, These are the patches that rework a few bits to make hot-unplug while ports are open not crash apps (or kernels). The problem is when hot-unplug is performed when a port is open, the cdev struct is kept around by the file pointers and when the app later does a 'close', things go boom-boom. This patch series makes sure port as well as device hot-unplug is now safe to perform

Hey Rusty, These are the patches that rework a few bits to make hot-unplug while ports are open not crash apps (or kernels). The problem is when hot-unplug is performed when a port is open, the cdev struct is kept around by the file pointers and when the app later does a 'close', things go boom-boom. This patch series makes sure port as well as device hot-unplug is now safe to perform

Unfortunately there proved to be at least one bug which requires an ABI change, so we're best off not introducing multiport support until 2.6.35. While I generally left the multiport code paths intact, I really wanted to remove the ABI defines from the header, which meant some quite deep cuts. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> To: Amit Shah <amit.shah at

Unfortunately there proved to be at least one bug which requires an ABI change, so we're best off not introducing multiport support until 2.6.35. While I generally left the multiport code paths intact, I really wanted to remove the ABI defines from the header, which meant some quite deep cuts. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> To: Amit Shah <amit.shah at

If a port was open before going into one of the sleep states, the port can continue normal operation after restore. However, the host has to be told that the guest side of the connection is open to restore pre-suspend state. This wasn't noticed so far due to a bug in qemu that was fixed recently (which marked the guest-side connection as always open). CC: stable at vger.kernel.org # Only

If a port was open before going into one of the sleep states, the port can continue normal operation after restore. However, the host has to be told that the guest side of the connection is open to restore pre-suspend state. This wasn't noticed so far due to a bug in qemu that was fixed recently (which marked the guest-side connection as always open). CC: stable at vger.kernel.org # Only

If we're using multiport, there's no point in always creating a console port. Create the console port only if the host doesn't support multiport. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/char/virtio_console.c | 32 +++++++++++++++----------------- 1 files changed, 15 insertions(+), 17 deletions(-) diff --git a/drivers/char/virtio_console.c

If we're using multiport, there's no point in always creating a console port. Create the console port only if the host doesn't support multiport. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/char/virtio_console.c | 32 +++++++++++++++----------------- 1 files changed, 15 insertions(+), 17 deletions(-) diff --git a/drivers/char/virtio_console.c

SIGIO should be sent when a port gets unplugged. It should only be sent to prcesses that have the port opened, and have asked for SIGIO to be delivered. We were clearing out guest_connected before calling send_sigio_to_port(), resulting in a sigio not getting sent to processes. Fix by setting guest_connected to false after invoking the sigio function. CC: <stable at vger.kernel.org>

Hello, This series fixes a few bugs and races with port unplug and the various file operations: read(), write() and close(). I started coding up an alternative locking mechanism based on the discussion earlier in this series, but some of what we already have has to remain, and the new code is sufficiently different, so I'd rather it bakes for a while, and I ensure there are no regressions

Hello, This series fixes a few bugs and races with port unplug and the various file operations: read(), write() and close(). I started coding up an alternative locking mechanism based on the discussion earlier in this series, but some of what we already have has to remain, and the new code is sufficiently different, so I'd rather it bakes for a while, and I ensure there are no regressions

Hey Rusty, Here are a few fixes for virtio and virtio_console. The first patch ensures the data elements of vqs are properly initialised at allocation-time so that we don't trigger BUG_ONs. I found this when hot-unplugging ports and there was just one unused buffer. detach_unused_buffers() kept returning pointers that were invalid. I didn't catch this earlier as I had the in_vq filled

Hey Rusty, Here are a few fixes for virtio and virtio_console. The first patch ensures the data elements of vqs are properly initialised at allocation-time so that we don't trigger BUG_ONs. I found this when hot-unplugging ports and there was just one unused buffer. detach_unused_buffers() kept returning pointers that were invalid. I didn't catch this earlier as I had the in_vq filled

Port unplug can race with close() in port_fops_release(). port_fops_release() already takes the necessary locks, ensure unplug_port() does that too. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/char/virtio_console.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 9cbed93..e8b707d 100644 ---

Amit Shah <amit.shah at redhat.com> writes: > There's a window between find_port_by_devt() returning a port and us > taking a kref on the port, where the port could get unplugged. Fix it > by taking the reference in find_port_by_devt() itself. > > Problem reported and analyzed by Mateusz Guzik. This fix is clearly correct, but what about the other find_port_by_*

Amit Shah <amit.shah at redhat.com> writes: > There's a window between find_port_by_devt() returning a port and us > taking a kref on the port, where the port could get unplugged. Fix it > by taking the reference in find_port_by_devt() itself. > > Problem reported and analyzed by Mateusz Guzik. This fix is clearly correct, but what about the other find_port_by_*

Hey Rusty, These updated patches in the series return -EFAULT on copy_xx_user errors and also move the copy_from_user into fops_write() instead of it being in send_buf. This enables send_buf to just read from kernel buffers, making it simpler. This also allows write()s to write more to the host in one go, removingthe 4k limitation. I do limit the writes to 32k at once to not put too much

Hey Rusty, These updated patches in the series return -EFAULT on copy_xx_user errors and also move the copy_from_user into fops_write() instead of it being in send_buf. This enables send_buf to just read from kernel buffers, making it simpler. This also allows write()s to write more to the host in one go, removingthe 4k limitation. I do limit the writes to 32k at once to not put too much

Hello, This series fixes a few bugs and races with port unplug and the various file operations: read(), write(), close() and poll(). There still might be more races lurking, but testing this series looks good to at least solve the easily-triggerable ones. I've run the virtio-serial testsuite and a few open/close/unplug tests, and haven't seen any badness. I've marked these patches

Hello, This series fixes a few bugs and races with port unplug and the various file operations: read(), write(), close() and poll(). There still might be more races lurking, but testing this series looks good to at least solve the easily-triggerable ones. I've run the virtio-serial testsuite and a few open/close/unplug tests, and haven't seen any badness. I've marked these patches