similar to: [PATCH 0/2] Fix hot-unplug: device removal while port in use

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

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

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

On 07/19/2013 04:16 AM, Amit Shah wrote: > We used to keep the port's char device structs and the /sys entries > around till the last reference to the port was dropped. This is > actually unnecessary, and resulted in buggy behaviour: > > 1. Open port in guest > 2. Hot-unplug port > 3. Hot-plug a port with the same 'name' property as the unplugged one > >

On 07/19/2013 04:16 AM, Amit Shah wrote: > We used to keep the port's char device structs and the /sys entries > around till the last reference to the port was dropped. This is > actually unnecessary, and resulted in buggy behaviour: > > 1. Open port in guest > 2. Hot-unplug port > 3. Hot-plug a port with the same 'name' property as the unplugged one > >

Hello, This series fixes a few 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 for

Hello, This series fixes a few 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 for

On 07/19/2013 01:02 PM, Amit Shah wrote: > On (Fri) 19 Jul 2013 [11:21:47], Jason Wang wrote: >> On 07/19/2013 04:16 AM, Amit Shah wrote: > >>> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c >>> index b04ec95..6bf0df3 100644 >>> --- a/drivers/char/virtio_console.c >>> +++ b/drivers/char/virtio_console.c >>> @@

On 07/19/2013 01:02 PM, Amit Shah wrote: > On (Fri) 19 Jul 2013 [11:21:47], Jason Wang wrote: >> On 07/19/2013 04:16 AM, Amit Shah wrote: > >>> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c >>> index b04ec95..6bf0df3 100644 >>> --- a/drivers/char/virtio_console.c >>> +++ b/drivers/char/virtio_console.c >>> @@

In the case where a virtio-console port is in use (opened by a program) and a virtio-console device is removed, the port is kept around but all the virtio-related state is assumed to be gone. When the port is finally released (close() called), we call device_destroy() on the port's device. This results in the parent device's structures to be freed as well. This includes the PCI regions

In the case where a virtio-console port is in use (opened by a program) and a virtio-console device is removed, the port is kept around but all the virtio-related state is assumed to be gone. When the port is finally released (close() called), we call device_destroy() on the port's device. This results in the parent device's structures to be freed as well. This includes the PCI regions

Turns out virtio console tries to take a buffer out of an active vq. Works by sheer luck, and is explicitly forbidden by spec. And while going over it I saw that error handling is also broken - failure is easy to trigger if I force allocations to fail. Lightly tested. Michael S. Tsirkin (6): virtio_console: don't tie bufs to a vq virtio: add ability to iterate over vqs virtio_console:

Turns out virtio console tries to take a buffer out of an active vq. Works by sheer luck, and is explicitly forbidden by spec. And while going over it I saw that error handling is also broken - failure is easy to trigger if I force allocations to fail. Lightly tested. Michael S. Tsirkin (6): virtio_console: don't tie bufs to a vq virtio: add ability to iterate over vqs virtio_console:

When removing a port we don't check if a program was blocked for read. This leads to a crash when SIGTERM is sent to the program after hot-unplugging the port. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/char/virtio_console.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c

When removing a port we don't check if a program was blocked for read. This leads to a crash when SIGTERM is sent to the program after hot-unplugging the port. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/char/virtio_console.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c

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