Re: [PATCH net] ice: fix locking around wait_event_interruptible_locked_irq

[Simon Horman <horms@kernel.org>]

On Fri, Mar 27, 2026 at 08:23:25AM +0100, Aleksandr Loktionov wrote:
> From: Jacob Keller <jacob.e.keller@intel.com>
> 
> Commit 50327223a8bb ("ice: add lock to protect low latency interface")
> introduced a wait queue used to protect the low latency timer interface.
> The queue is used with the wait_event_interruptible_locked_irq macro, which
> unlocks the wait queue lock while sleeping. The irq variant uses
> spin_lock_irq and spin_unlock_irq to manage this. The wait queue lock was
> previously locked using spin_lock_irqsave. This difference in lock variants
> could lead to issues, since wait_event would unlock the wait queue and
> restore interrupts while sleeping.
> 
> The ice_read_phy_tstamp_ll_e810() function is ultimately called through
> ice_read_phy_tstamp, which is called from ice_ptp_process_tx_tstamp or
> ice_ptp_clear_unexpected_tx_ready. The former is called through the
> miscellaneous IRQ thread function, while the latter is called from the
> service task work queue thread. Neither of these functions has interrupts
> disabled, so use spin_lock_irq instead of spin_lock_irqsave.
> 
> Fixes: 50327223a8bb ("ice: add lock to protect low latency interface")
> Cc: stable@vger.kernel.org
> Reported-by: Jakub Kicinski <kuba@kernel.org>
> Closes: https://lore.kernel.org/netdev/20250109181823.77f44c69@kernel.org/
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>