From: Christian Eggers Date: Tue, 11 Mar 2025 09:18:02 +0000 (+0100) Subject: regulator: dummy: force synchronous probing X-Git-Tag: v6.14~6^2~3 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=8619909b38eeebd3e60910158d7d68441fc954e9;p=linux-block.git regulator: dummy: force synchronous probing Sometimes I get a NULL pointer dereference at boot time in kobject_get() with the following call stack: anatop_regulator_probe() devm_regulator_register() regulator_register() regulator_resolve_supply() kobject_get() By placing some extra BUG_ON() statements I could verify that this is raised because probing of the 'dummy' regulator driver is not completed ('dummy_regulator_rdev' is still NULL). In the JTAG debugger I can see that dummy_regulator_probe() and anatop_regulator_probe() can be run by different kernel threads (kworker/u4:*). I haven't further investigated whether this can be changed or if there are other possibilities to force synchronization between these two probe routines. On the other hand I don't expect much boot time penalty by probing the 'dummy' regulator synchronously. Cc: stable@vger.kernel.org Fixes: 259b93b21a9f ("regulator: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in 4.14") Signed-off-by: Christian Eggers Link: https://patch.msgid.link/20250311091803.31026-1-ceggers@arri.de Signed-off-by: Mark Brown --- diff --git a/drivers/regulator/dummy.c b/drivers/regulator/dummy.c index 5b9b9e4e762d..9f59889129ab 100644 --- a/drivers/regulator/dummy.c +++ b/drivers/regulator/dummy.c @@ -60,7 +60,7 @@ static struct platform_driver dummy_regulator_driver = { .probe = dummy_regulator_probe, .driver = { .name = "reg-dummy", - .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .probe_type = PROBE_FORCE_SYNCHRONOUS, }, };