In the Linux kernel, the following vulnerability has been resolved:

mmc: davinci: avoid NULL deref of host->data in IRQ handler

mmc davinci irq() returns early only when both host->cmd and host->data are NULL:

if (host->cmd == NULL && host->data == NULL) { ... return IRQ NONE; }

So we may legitimately reach the rest of the handler with host->data == NULL (and therefore data == NULL). The DATDNE branch already guards against this with an explicit "if (data != NULL)" check, but the subsequent TOUTRD ("read data timeout") and CRCWR/CRCRD ("data CRC error") branches dereference data unconditionally:

if (qstatus & MMCST0 TOUTRD) { data->error = -ETIMEDOUT; <-- NULL deref ... davinci abort data(host, data); }

if (qstatus & (MMCST0 CRCWR | MMCST0 CRCRD)) { data->error = -EILSEQ; <-- NULL deref ... }

If either bit is set in qstatus while host->data is NULL, the kernel will crash inside the IRQ handler. smatch flags this:

drivers/mmc/host/davinci mmc.c:933 mmc davinci irq() error: we previously assumed 'data' could be null (see line 914)

Gate both branches on a non-NULL data, matching the existing pattern used by the DATDNE branch.

No functional change for callers where data is non-NULL, which is the only case in which these branches did meaningful work before this change.