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eeprom: at24: fix memory corruption race condition 

If the eeprom is not accessible, an nvmem device will be registered, the
read will fail, and the device will be torn down. If another driver
accesses the nvmem device after the teardown, it will reference
invalid memory.

Move the failure point before registering the nvmem device.

Signed-off-by: Daniel Okazaki <dtokazaki@google.com>
Fixes: b20eb4c1f0 ("eeprom: at24: drop unnecessary label")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240422174337.2487142-1-dtokazaki@google.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Daniel Okazaki 2024-04-22 17:43:36 +00:00 committed by Bartosz Golaszewski
parent b3de7b433a
commit f42c97027f
1 changed files with 9 additions and 9 deletions
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18
drivers/misc/eeprom/at24.c
View File

@ -758,15 +758,6 @@ static int at24_probe(struct i2c_client *client)
}
pm_runtime_enable(dev);
at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
if (IS_ERR(at24->nvmem)) {
pm_runtime_disable(dev);
if (!pm_runtime_status_suspended(dev))
regulator_disable(at24->vcc_reg);
return dev_err_probe(dev, PTR_ERR(at24->nvmem),
"failed to register nvmem\n");
}
/*
* Perform a one-byte test read to verify that the chip is functional,
* unless powering on the device is to be avoided during probe (i.e.
@ -782,6 +773,15 @@ static int at24_probe(struct i2c_client *client)
}
}
at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
if (IS_ERR(at24->nvmem)) {
pm_runtime_disable(dev);
if (!pm_runtime_status_suspended(dev))
regulator_disable(at24->vcc_reg);
return dev_err_probe(dev, PTR_ERR(at24->nvmem),
"failed to register nvmem\n");
}
/* If this a SPD EEPROM, probe for DDR3 thermal sensor */
if (cdata == &at24_data_spd)
at24_probe_temp_sensor(client);