Messages in this thread Patch in this message | | | From | Martin Fuzzey <> | Subject | [PATCH v2] regulator: da9063: fix null pointer deref with partial DT config | Date | Thu, 22 Jun 2023 17:11:02 +0200 |
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When some of the da9063 regulators do not have corresponding DT nodes a null pointer dereference occurs on boot:
[ 1.559034] 8<--- cut here --- [ 1.564014] Unable to handle kernel NULL pointer dereference at virtual address 00000098 when read [ 1.578055] [00000098] *pgd=00000000 [ 1.593575] Internal error: Oops: 5 [#1] SMP ARM [ 1.634870] PC is at da9063_regulator_probe+0x35c/0x788 [ 1.647934] LR is at da9063_regulator_probe+0x2e8/0x788 [ 2.073626] da9063_regulator_probe from platform_probe+0x58/0xb8 [ 2.079759] platform_probe from really_probe+0xd8/0x3c0 [ 2.085092] really_probe from __driver_probe_device+0x94/0x1e8 [ 2.091026] __driver_probe_device from driver_probe_device+0x2c/0xd0 [ 2.097479] driver_probe_device from __device_attach_driver+0xa4/0x11c [ 2.104107] __device_attach_driver from bus_for_each_drv+0x84/0xdc [ 2.110402] bus_for_each_drv from __device_attach_async_helper+0xb0/0x110 [ 2.117295] __device_attach_async_helper from async_run_entry_fn+0x3c/0x158 [ 2.124369] async_run_entry_fn from process_one_work+0x1d4/0x3e4 [ 2.130485] process_one_work from worker_thread+0x30/0x520 [ 2.136070] worker_thread from kthread+0xdc/0xfc
This is because such regulators have no init_data causing the pointers calculated in da9063_check_xvp_constraints() to be invalid.
Do not dereference them in this case.
Fixes: b8717a80e6ee ("regulator: da9063: implement setter for voltage monitoring") Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group> ---
Changes since V1: - Following review by Mark Brown avoid previous dereferences too. With the GCC versions I tried this didn't cause problems because it only takes the address ie &config->init_data->constraints doesn't fault if config->init_data is NULL (it would without the &) But this behaviour isn't guaranteed and other compilers or compiler versions could behave differently so completely avoid calling the function if config->init_data is NULL.
drivers/regulator/da9063-regulator.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/regulator/da9063-regulator.c b/drivers/regulator/da9063-regulator.c index c5dd77be558b..a0621665a6d2 100644 --- a/drivers/regulator/da9063-regulator.c +++ b/drivers/regulator/da9063-regulator.c @@ -1028,9 +1028,12 @@ static int da9063_regulator_probe(struct platform_device *pdev) config.of_node = da9063_reg_matches[id].of_node; config.regmap = da9063->regmap; - ret = da9063_check_xvp_constraints(&config); - if (ret) - return ret; + /* Checking constraints requires init_data from DT. */ + if (config.init_data) { + ret = da9063_check_xvp_constraints(&config); + if (ret) + return ret; + } regl->rdev = devm_regulator_register(&pdev->dev, ®l->desc, &config); -- 2.25.1
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