On 03/19/2018 10:48 AM, Sasha Levin wrote:
From: David Lechner <david@xxxxxxxxxxxxxx> [ Upstream commit a12aa8a68dfef5de181f2e555aa950a0ab05411f ] Reentrant calls to clk_enable() are not working on UP systems. This is caused by the fact spin_trylock_irqsave() always returns true when CONFIG_SMP=n (and CONFIG_DEBUG_SPINLOCK=n) which causes the reference counting to not work correctly when clk_enable_lock() is called twice before clk_enable_unlock() is called (this happens when clk_enable() is called from within another clk_enable()). This fixes the problem by skipping the call to spin_trylock_irqsave() on UP systems and relying solely on reference counting. We also make sure to set flags in this case so that we are not returning an uninitialized value. Suggested-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> ---
I don't know of any existing bugs in v4.15 that this fixes, so I don't think this really fits the criteria for stable.