V4L/DVB (5818): CinergyT2: fix flush_workqueue() vs work->func() deadlock

Spotted and tested by Thomas Sattler <[email protected]>.

cinergyT2.c does cancel_delayed_work() + flush_scheduled_work() while
holding cinergyt2->sem. This leads to deadlock because work->func()
needs the same mutex to complete. Another bug is that this code in fact
can't reliably stop the re-arming delayed_work.

Convert this code to use cancel_rearming_delayed_work() and move it
out of ->sem. Another mutex, ->wq_sem, was added to protect against the
concurrent open/resume.

This patch is a horrible hack to fix the lockup which happens in practice.
As Dmitry Torokhov pointed out this driver has other problems and needs
further changes.

Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

0 files changed, 0 insertions, 0 deletions