tree 8e24e52483d472a3879f37a4e56808b6ec40b5aa
parent bb75c00bad0d04025b00991fe16db2fc0504ce58
author Roberto Sassu <roberto.sassu@huawei.com> 1709808566 +0100
committer Vegard Nossum <vegard.nossum@oracle.com> 1721065470 +0000

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>