The code does not properly check whether the calibration variable is available in the EFI. If it is not available, it causes a NULL pointer dereference. Check the return value of the first get_variable call also. BUG: kernel NULL pointer dereference, address: 0000000000000000 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x171/0x4e0 ? srso_alias_return_thunk+0x5/0x7f ? schedule+0x5e/0xd0 ? exc_page_fault+0x7f/0x180 ? asm_exc_page_fault+0x26/0x30 ? crc32_body+0x2c/0x120 ? tas2781_save_calibration+0xe4/0x220 [snd_hda_scodec_tas2781_i2c] tasdev_fw_ready+0x1af/0x280 [snd_hda_scodec_tas2781_i2c] request_firmware_work_func+0x59/0xa0 Fixes: 5be27f1e3ec9 ("ALSA: hda/tas2781: Add tas2781 HDA driver") CC: stable@vger.kernel.org Signed-off-by: Gergo Koteles <soyer@irl.hu> Link: https://lore.kernel.org/r/f1f6583bda918f78556f67d522ca7b3b91cebbd5.1702251102.git.soyer@irl.hu Signed-off-by: Takashi Iwai <tiwai@suse.de>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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