5.4-stable review patch. If anyone has any objections, please let me know.
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From: Alessandro Carminati acarmina@redhat.com
[ Upstream commit ca46946a482238b0cdea459fb82fc837fb36260e ]
Failing to reset coupling_desc.n_coupled after freeing coupled_rdevs can lead to NULL pointer dereference when regulators are accessed post-unbind.
This can happen during runtime PM or other regulator operations that rely on coupling metadata.
For example, on ridesx4, unbinding the 'reg-dummy' platform device triggers a panic in regulator_lock_recursive() due to stale coupling state.
Ensure n_coupled is set to 0 to prevent access to invalid pointers.
Signed-off-by: Alessandro Carminati acarmina@redhat.com Link: https://patch.msgid.link/20250626083809.314842-1-acarmina@redhat.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/regulator/core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index a01a769b2f2d1..e5ce97dc32158 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5062,6 +5062,7 @@ static void regulator_remove_coupling(struct regulator_dev *rdev) err); }
+ rdev->coupling_desc.n_coupled = 0; kfree(rdev->coupling_desc.coupled_rdevs); rdev->coupling_desc.coupled_rdevs = NULL; }