9 Dec
2020
9 Dec
'20
4:10 a.m.
On Thu, Dec 3, 2020 at 9:07 PM Andy Lutomirski luto@kernel.org wrote:
sync_core_before_usermode() had an incorrect optimization. If we're in an IRQ, we can get to usermode without IRET -- we just have to schedule to a different task in the same mm and do SYSRET. Fortunately, there were no callers of sync_core_before_usermode() that could have had in_irq() or in_nmi() equal to true, because it's only ever called from the scheduler.
While we're at it, clarify a related comment.
Fixes: ac1ab12a3e6e ("lockin/x86: Implement sync_core_before_usermode()")
Cc: stable@vger.kernel.org Reviewed-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Signed-off-by: Andy Lutomirski luto@kernel.org