Commits
Waiman Long committed 710d9fd2f48
locking/rwsem: Fix kernel crash when spinning on RWSEM_OWNER_UNKNOWN commit 39e7234f00bc93613c086ae42d852d5f4147120a upstream. The commit 91d2a812dfb9 ("locking/rwsem: Make handoff writer optimistically spin on owner") will allow a recently woken up waiting writer to spin on the owner. Unfortunately, if the owner happens to be RWSEM_OWNER_UNKNOWN, the code will incorrectly spin on it leading to a kernel crash. This is fixed by passing the proper non-spinnable bits to rwsem_spin_on_owner() so that RWSEM_OWNER_UNKNOWN will be treated as a non-spinnable target. Fixes: 91d2a812dfb9 ("locking/rwsem: Make handoff writer optimistically spin on owner") Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200115154336.8679-1-longman@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>