[ Upstream commit b2d102bd ]
This bug occurs when:
- a new request arrives, one thread(let's call it A) is pending in
optee_supp_req() with req->busy is initial value false.
- tee-supplicant is killed, then optee_supp_release() is called, this
function calls list_del(&req->link), and set supp->ctx to NULL. And
it also wake up process A.
- process A continues, it firstly checks supp->ctx which is NULL,
then checks req->busy which is false, at last run list_del(&req->link).
This triggers double list_del() and results kernel panic.
For solve this problem, we rename req->busy to req->in_queue, and
associate it with state of whether req is linked to supp->reqs. So we
can just only check req->in_queue to make decision calling list_del()
Signed-off-by: Zhizhou Zhang <email@example.com>
Signed-off-by: Jens Wiklander <firstname.lastname@example.org>
Signed-off-by: Sasha Levin <email@example.com>