Re: [PATCH] tpm: fix NPE on probe for missing device

On Thu, Dec 23, 2021 at 09:49:31AM -0600, Patrick Williams wrote:

When using the tpm_tis-spi driver on a system missing the physical TPM, a null pointer exception was observed.

[    0.938677] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[    0.939020] pgd = 10c753cb
[    0.939237] [00000004] *pgd=00000000
[    0.939808] Internal error: Oops: 5 [#1] SMP ARM
[    0.940157] CPU: 0 PID: 48 Comm: kworker/u4:1 Not tainted 5.15.10-dd1e40c #1
[    0.940364] Hardware name: Generic DT based system
[    0.940601] Workqueue: events_unbound async_run_entry_fn
[    0.941048] PC is at tpm_tis_remove+0x28/0xb4
[    0.941196] LR is at tpm_tis_core_init+0x170/0x6ac

This is due to an attempt in 'tpm_tis_remove' to use the drvdata, which was not initialized in 'tpm_tis_core_init' prior to the first error.

Move the initialization of drvdata earlier so 'tpm_tis_remove' has access to it.

Signed-off-by: Patrick Williams patrick@stwcx.xyz Fixes: 79ca6f74dae0 ("tpm: fix Atmel TPM crash caused by too frequent queries") Cc: stable@vger.kernel.org

Thank you.

Reviewed-by: Jarkko Sakkinen jarkko@kernel.org

/Jarkko