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| author | Christian Eggers <ceggers@arri.de> | 2025-03-11 10:18:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-03-28 22:04:55 +0100 |
| commit | 5ade367b56c3947c990598df92395ce737bee872 (patch) | |
| tree | 9a0db29cab3375f03d330197273bddfb671b4add | |
| parent | c2d5d14a7bcbb045d0cd0095cefe95f2a4b91159 (diff) | |
| download | linux-5ade367b56c3947c990598df92395ce737bee872.tar.gz linux-5ade367b56c3947c990598df92395ce737bee872.tar.bz2 linux-5ade367b56c3947c990598df92395ce737bee872.zip | |
regulator: dummy: force synchronous probing
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: 259b93b21a9f ("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>
| -rw-r--r-- | drivers/regulator/dummy.c | 2 |
1 files changed, 1 insertions, 1 deletions
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, }, }; |