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tpm: fix NPE on probe for missing device
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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: 79ca6f7 ("tpm: fix Atmel TPM crash caused by too frequent queries")
Cc: stable@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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williamspatrick authored and jarkkojs committed Jan 8, 2022
1 parent eabad7b commit 84cc695
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions drivers/char/tpm/tpm_tis_core.c
Original file line number Diff line number Diff line change
Expand Up @@ -950,6 +950,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
priv->timeout_max = TPM_TIMEOUT_USECS_MAX;
priv->phy_ops = phy_ops;

dev_set_drvdata(&chip->dev, priv);

rc = tpm_tis_read32(priv, TPM_DID_VID(0), &vendor);
if (rc < 0)
return rc;
Expand All @@ -962,8 +964,6 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
priv->timeout_max = TIS_TIMEOUT_MAX_ATML;
}

dev_set_drvdata(&chip->dev, priv);

if (is_bsw()) {
priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR,
ILB_REMAP_SIZE);
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