Commit Graph

10 Commits

Author SHA1 Message Date
Alex Ng e66853b090 Drivers: hv: utils: Remove util transport handler from list if registration fails
If util transport fails to initialize for any reason, the list of transport
handlers may become corrupted due to freeing the transport handler without
removing it from the list. Fix this by cleaning it up from the list.

Signed-off-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-01 16:57:20 -08:00
Vitaly Kuznetsov 77b744a598 Drivers: hv: utils: fix hvt_op_poll() return value on transport destroy
The return type of hvt_op_poll() is unsigned int and -EBADF is
inappropriate, poll functions return POLL* statuses.

Reported-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-21 13:14:56 -08:00
Vitaly Kuznetsov 9420098adc Drivers: hv: utils: fix crash when device is removed from host side
The crash is observed when a service is being disabled host side while
userspace daemon is connected to the device:

[   90.244859] general protection fault: 0000 [#1] SMP
...
[   90.800082] Call Trace:
[   90.800082]  [<ffffffff81187008>] __fput+0xc8/0x1f0
[   90.800082]  [<ffffffff8118716e>] ____fput+0xe/0x10
...
[   90.800082]  [<ffffffff81015278>] do_signal+0x28/0x580
[   90.800082]  [<ffffffff81086656>] ? finish_task_switch+0xa6/0x180
[   90.800082]  [<ffffffff81443ebf>] ? __schedule+0x28f/0x870
[   90.800082]  [<ffffffffa01ebbaa>] ? hvt_op_read+0x12a/0x140 [hv_utils]
...

The problem is that hvutil_transport_destroy() which does misc_deregister()
freeing the appropriate device is reachable by two paths: module unload
and from util_remove(). While module unload path is protected by .owner in
struct file_operations util_remove() path is not. Freeing the device while
someone holds an open fd for it is a show stopper.

In general, it is not possible to revoke an fd from all users so the only
way to solve the issue is to defer freeing the hvutil_transport structure.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:27:30 -08:00
Vitaly Kuznetsov a15025660d Drivers: hv: utils: introduce HVUTIL_TRANSPORT_DESTROY mode
When Hyper-V host asks us to remove some util driver by closing the
appropriate channel there is no easy way to force the current file
descriptor holder to hang up but we can start to respond -EBADF to all
operations asking it to exit gracefully.

As we're setting hvt->mode from two separate contexts now we need to use
a proper locking.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:27:30 -08:00
Vitaly Kuznetsov a72f3a4ccf Drivers: hv: utils: rename outmsg_lock
As a preparation to reusing outmsg_lock to protect test-and-set openrations
on 'mode' rename it the more general 'lock'.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:27:30 -08:00
Vitaly Kuznetsov 1f75338b6f Drivers: hv: utils: fix memory leak on on_msg() failure
inmsg should be freed in case of on_msg() failure to avoid memory leak.
Preserve the error code from on_msg().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:27:30 -08:00
Olaf Hering b00359642c Drivers: hv: utils: use memdup_user in hvt_op_write
Use memdup_user to handle OOM.

Fixes: 14b50f80c3 ('Drivers: hv: util: introduce hv_utils_transport abstraction')

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:12:21 -08:00
Olaf Hering cdc0c0c94e Drivers: hv: util: catch allocation errors
Catch allocation errors in hvutil_transport_send.

Fixes: 14b50f80c3 ('Drivers: hv: util: introduce hv_utils_transport abstraction')

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-14 19:12:21 -08:00
Dan Carpenter 9dd6a06430 hv: util: checking the wrong variable
We don't catch this allocation failure because there is a typo and we
check the wrong variable.

Fixes: 14b50f80c3 ('Drivers: hv: util: introduce hv_utils_transport abstraction')

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:29:45 -07:00
Vitaly Kuznetsov 14b50f80c3 Drivers: hv: util: introduce hv_utils_transport abstraction
The intention is to make KVP/VSS drivers work through misc char devices.
Introduce an abstraction for kernel/userspace communication to make the
migration smoother. Transport operational mode (netlink or char device)
is determined by the first received message. To support driver upgrades
the switch from netlink to chardev operational mode is supported.

Every hv_util daemon is supposed to register 2 callbacks:
1) on_msg() to get notified when the userspace daemon sent a message;
2) on_reset() to get notified when the userspace daemon drops the connection.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 12:17:41 -07:00