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.