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e26f24ca4f
commit 8619909b38eeebd3e60910158d7d68441fc954e9 upstream.
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: 259b93b21a ("regulator: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in 4.14")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Link: https://patch.msgid.link/20250311091803.31026-1-ceggers@arri.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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