From: Alexander Shishkin Date: Fri, 5 Jul 2019 14:14:24 +0000 (+0300) Subject: intel_th: msu: Prevent freeing buffers while locked windows exist X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ed5207afc580937cd6cc671357fe1119f1b5b0f5;p=linux.git intel_th: msu: Prevent freeing buffers while locked windows exist We already prevent freeing buffers via sysfs interface in case there are existing users or if trace is active. Treat the existence of locked windows similarly and return -EBUSY on attempts to free the buffer. When the last window is unlocked, the freeing will succeed. Signed-off-by: Alexander Shishkin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20190705141425.19894-5-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index a6c0eb09c5158..b200d9d1c7a03 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -724,6 +724,11 @@ static int msc_win_set_lockout(struct msc_window *win, win->lockout = new; + if (old == expect && new == WIN_LOCKED) + atomic_inc(&win->msc->user_count); + else if (old == expect && old == WIN_LOCKED) + atomic_dec(&win->msc->user_count); + unlock: spin_unlock_irqrestore(&win->lo_lock, flags);