[PATCH 4.2.y-ckt 24/70] [media] au0828: fix au0828_v4l2_close() dev_state race condition

From	Kamal Mostafa <kamal@canonical.com>
Newsgroups	linux.kernel
Subject	[PATCH 4.2.y-ckt 24/70] [media] au0828: fix au0828_v4l2_close() dev_state race condition
Date	2016-04-12 23:40 +0200
Message-ID	<rnecq-5Ws-5@gated-at.bofh.it> (permalink)
References	<rndzH-5be-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.2.8-ckt8 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Shuah Khan <shuahkh@osg.samsung.com>

commit ed940cd27416f9887864b95e1f8f8845aa9d6391 upstream.

au0828_v4l2_close() check for dev_state == DEV_DISCONNECTED will fail to
detect the device disconnected state correctly, if au0828_v4l2_open() runs
to set the DEV_INITIALIZED bit. A loop test of bind/unbind found this bug
by increasing the likelihood of au0828_v4l2_open() occurring while unbind
is in progress. When au0828_v4l2_close() fails to detect that the device
is in disconnect state, it attempts to power down the device and fails with
the following general protection fault:

[  260.992962] Call Trace:
[  260.993008]  [<ffffffffa0f80f0f>] ? xc5000_sleep+0x8f/0xd0 [xc5000]
[  260.993095]  [<ffffffffa0f6803c>] ? fe_standby+0x3c/0x50 [tuner]
[  260.993186]  [<ffffffffa0ef541c>] au0828_v4l2_close+0x53c/0x620 [au0828]
[  260.993298]  [<ffffffffa0d08ec0>] v4l2_release+0xf0/0x210 [videodev]
[  260.993382]  [<ffffffff81570f9c>] __fput+0x1fc/0x6c0
[  260.993449]  [<ffffffff815714ce>] ____fput+0xe/0x10
[  260.993519]  [<ffffffff8116eb83>] task_work_run+0x133/0x1f0
[  260.993602]  [<ffffffff810035d0>] exit_to_usermode_loop+0x140/0x170
[  260.993681]  [<ffffffff810061ca>] syscall_return_slowpath+0x16a/0x1a0
[  260.993754]  [<ffffffff82835fb3>] entry_SYSCALL_64_fastpath+0xa6/0xa8

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/media/usb/au0828/au0828-video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c
index 1a362a0..5cc2bb1 100644
--- a/drivers/media/usb/au0828/au0828-video.c
+++ b/drivers/media/usb/au0828/au0828-video.c
@@ -1001,7 +1001,7 @@ static int au0828_v4l2_close(struct file *filp)
 		del_timer_sync(&dev->vbi_timeout);
 	}
 
-	if (dev->dev_state == DEV_DISCONNECTED)
+	if (dev->dev_state & DEV_DISCONNECTED)
 		goto end;
 
 	if (dev->users == 1) {
-- 
2.7.4

Thread

[4.2.y-ckt stable] Linux 4.2.8-ckt8 stable review Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 69/70] mwifiex: fix corner case association failure Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 35/70] ext4: ignore quota mount options if the quota feature is enabled Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 64/70] lib/ucs2_string: Correct ucs2 -> utf8 conversion Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 63/70] efi: Add pstore variables to the deletion whitelist Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 65/70] ipr: Fix out-of-bounds null overwrite Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 22/70] USB: cypress_m8: add endpoint sanity check Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 62/70] efi: Make efivarfs entries immutable by default Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 61/70] efi: Make our variable validation list include the guid Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 09/70] hwmon: (max1111) Return -ENODEV from max1111_read_channel if not instantiated Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 70/70] net: phy: at803x: Request 'reset' GPIO only for AT8030 PHY Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:00 +0200
  [PATCH 4.2.y-ckt 42/70] USB: serial: ftdi_sio: Add support for ICP DAS I-756xU devices Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 49/70] parisc: Fix kernel crash with reversed copy_from_user() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 55/70] pinctrl: nomadik: fix pull debug print inversion Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 38/70] mac80211: properly deal with station hashtable insert errors Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 39/70] compiler-gcc: disable -ftracer for __noclone functions Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 47/70] gpio: pca953x: Use correct u16 value for register word write Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 36/70] xen/events: Mask a moving irq Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 43/70] USB: serial: cp210x: Adding GE Healthcare Device ID Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 41/70] Btrfs: fix file/data loss caused by fsync after rename and new inode Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 33/70] mm: fix invalid node in alloc_migrate_target() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 57/70] KVM: x86: move steal time initialization to vcpu entry time Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 37/70] usb: renesas_usbhs: fix to avoid using a disabled ep in usbhsg_queue_done() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 40/70] rbd: use GFP_NOIO consistently for request allocations Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 50/70] parisc: Unbreak handling exceptions from kernel modules Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 52/70] net: bcmgenet: fix dev->stats.tx_bytes accounting Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 31/70] KVM: x86: Inject pending interrupt even if pending nmi exist Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 34/70] iio: st_magn: always define ST_MAGN_TRIGGER_SET_STATE Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 48/70] parisc: Avoid function pointers for kernel exception routines Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 56/70] ip6_tunnel: set rtnl_link_ops before calling register_netdevice Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 45/70] virtio: virtio 1.0 cs04 spec compliance for reset Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 54/70] ipv6: udp: fix UDP_MIB_IGNOREDMULTI updates Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 44/70] USB: option: add "D-Link DWM-221 B1" device id Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:30 +0200
  [PATCH 4.2.y-ckt 30/70] ALSA: hda - fix front mic problem for a HP desktop Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 27/70] drm/dp: move hw_mutex up the call stack Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 08/70] nfs: use file_dentry() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 24/70] [media] au0828: fix au0828_v4l2_close() dev_state race condition Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 02/70] PKCS#7: pkcs7_validate_trust(): initialize the _trusted output argument Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 16/70] usb: renesas_usbhs: avoid NULL pointer derefernce in usbhsf_pkt_handler() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 10/70] drm/radeon: add another R7 370 quirk Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 20/70] ALSA: usb-audio: Fix double-free in error paths after snd_usb_add_audio_stream() call Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 05/70] ALSA: hda - Apply fix for white noise on Asus N550JV, too Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 26/70] sd: Fix excessive capacity printing on devices with blocks bigger than 512 bytes Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 23/70] USB: digi_acceleport: do sanity checking for the number of ports Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 32/70] ALSA: timer: Use mod_timer() for rearming the system timer Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 14/70] pinctrl: pistachio: fix mfio84-89 function description and pinmux. Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 15/70] pinctrl: sunxi: Fix A33 external interrupts not working Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 28/70] drm/udl: Use unlocked gem unreferencing Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 03/70] ALSA: hda - Asus N750JV external subwoofer fixup Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 12/70] powerpc/mm: Fixup preempt underflow with huge pages Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 04/70] ALSA: hda - Fix white noise on Asus N750JV headphone Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 18/70] btrfs: fix crash/invalid memory access on fsync when using overlayfs Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 29/70] ext4: add lockdep annotations for i_data_sem Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 11/70] drm/radeon: add a dpm quirk for all R7 370 parts Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 13/70] pinctrl: sh-pfc: only use dummy states for non-DT platforms Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 17/70] usb: renesas_usbhs: disable TX IRQ before starting TX DMAC transfer Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 21/70] USB: mct_u232: add sanity checking in probe Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 25/70] [media] au0828: Fix dev_state handling Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200
  [PATCH 4.2.y-ckt 07/70] fs: add file_dentry() Kamal Mostafa <kamal@canonical.com> - 2016-04-12 23:40 +0200

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