linux-toradex.git/drivers/char/virtio_console.c, branch v4.10

virtio_console: fix a crash in config_work_handler

2017-01-19T21:46:31+00:00

Using control_work instead of config_work as the 3rd argument to
container_of results in an invalid portdev pointer. Indeed, the work
structure is initialized as below:

    INIT_WORK(&portdev->config_work, &config_work_handler);

It leads to a crash when portdev->vdev is dereferenced later. This
bug
is triggered when the guest uses a virtio-console without multiport
feature and receives a config_changed virtio interrupt.

Signed-off-by: G. Campana 
Reviewed-by: Amit Shah 
Signed-off-by: Michael S. Tsirkin

virtio_console: drop unused config fields

2016-12-15T04:59:15+00:00

struct ports_device includes a config field including the whole
virtio_console_config, but only max_nr_ports in there is ever updated or
used. The rest is unused and in fact does not even mirror the
device config. Drop everything except max_nr_ports,
saving some memory.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Jason Wang

virtio: console: Unlock vqs while freeing buffers

2016-10-30T22:21:44+00:00

Commit c6017e793b93 ("virtio: console: add locks around buffer removal
in port unplug path") added locking around the freeing of buffers in the
vq. However, when free_buf() is called with can_sleep = true and rproc
is enabled, it calls dma_free_coherent() directly, requiring interrupts
to be enabled. Currently a WARNING is triggered due to the spin locking
around free_buf, with a call stack like this:

WARNING: CPU: 3 PID: 121 at ./include/linux/dma-mapping.h:433
free_buf+0x1a8/0x288
Call Trace:
[<8040c538>] show_stack+0x74/0xc0
[<80757240>] dump_stack+0xd0/0x110
[<80430d98>] __warn+0xfc/0x130
[<80430ee0>] warn_slowpath_null+0x2c/0x3c
[<807e7c6c>] free_buf+0x1a8/0x288
[<807ea590>] remove_port_data+0x50/0xac
[<807ea6a0>] unplug_port+0xb4/0x1bc
[<807ea858>] virtcons_remove+0xb0/0xfc
[<807b6734>] virtio_dev_remove+0x58/0xc0
[<807f918c>] __device_release_driver+0xac/0x134
[<807f924c>] device_release_driver+0x38/0x50
[<807f7edc>] bus_remove_device+0xfc/0x130
[<807f4b74>] device_del+0x17c/0x21c
[<807f4c38>] device_unregister+0x24/0x38
[<807b6b50>] unregister_virtio_device+0x28/0x44

Fix this by restructuring the loops to allow the locks to only be taken
where it is necessary to protect the vqs, and release it while the
buffer is being freed.

Fixes: c6017e793b93 ("virtio: console: add locks around buffer removal in port unplug path")
Cc: stable@vger.kernel.org
Signed-off-by: Matt Redfearn 
Signed-off-by: Michael S. Tsirkin

treewide: remove redundant #include

2016-10-11T22:06:33+00:00

Kernel source files need not include  explicitly
because the top Makefile forces to include it with:

  -include $(srctree)/include/linux/kconfig.h

This commit removes explicit includes except the following:

  * arch/s390/include/asm/facilities_src.h
  * tools/testing/radix-tree/linux/kernel.h

These two are used for host programs.

Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pipe: add pipe_buf_steal() helper

2016-10-05T22:23:59+00:00

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro

virtio_console: Stop doing DMA on the stack

2016-09-09T18:12:45+00:00

virtio_console uses a small DMA buffer for control requests.  Move
that buffer into heap memory.

Doing virtio DMA on the stack is normally okay on non-DMA-API virtio
systems (which is currently most of them), but it breaks completely
if the stack is virtually mapped.

Tested by typing both directions using picocom aimed at /dev/hvc0.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Amit Shah

virtio_console: silence a static checker warning

2015-05-24T19:24:35+00:00

My static checker complains that this sprintf() can overflow but really
it can't.  Just silence the warning by using snprintf().

Signed-off-by: Dan Carpenter 
Reviewed-by: Amit Shah 
Signed-off-by: Greg Kroah-Hartman

virtio_console: Use bool function return values of true/false not 1/0

2015-04-03T14:15:30+00:00

Use the normal return values for bool functions

Signed-off-by: Joe Perches 
Reviewed-by: Amit Shah 
Signed-off-by: Greg Kroah-Hartman

virtio_console: avoid config access from irq

2015-03-05T03:06:18+00:00

when multiport is off, virtio console invokes config access from irq
context, config access is blocking on s390.
Fix this up by scheduling work from config irq - similar to what we do
for multiport configs.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Amit Shah 
Signed-off-by: Rusty Russell 
Cc: stable@kernel.org

virtio_console: init work unconditionally

2015-03-05T03:06:17+00:00

when multiport is off, we don't initialize config work,
but we then cancel uninitialized control_work on freeze.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Amit Shah 
Signed-off-by: Rusty Russell 
Cc: stable@kernel.org