um: Add winch to winch_handlers before registering winch IRQ
[ Upstream commit a0fbbd36c156b9f7b2276871d499c9943dfe5101 ]
Registering a winch IRQ is racy, an interrupt may occur before the winch is
added to the winch_handlers list.
If that happens, register_winch_irq() adds to that list a winch that is
scheduled to be (or has already been) freed, causing a panic later in
winch_cleanup().
Avoid the race by adding the winch to the winch_handlers list before
registering the IRQ, and rolling back if um_request_irq() fails.
Fixes: 42a359e31a0e ("uml: SIGIO support cleanup")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 66ea9a7c6824821476914bed21a476cd20094f33)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
1 file changed