[bug report] mailbox: Introduce support for T-head TH1520 Mailbox driver

[Dan Carpenter]

Hello Michal Wilczynski,

Commit 5d4d263e1c6b ("mailbox: Introduce support for T-head TH1520
Mailbox driver") from Nov 4, 2024 (linux-next), leads to the
following Smatch static checker warning:

drivers/mailbox/mailbox-th1520.c:535 th1520_mbox_suspend_noirq() error: buffer overflow 'ctx->intr_mask' 3 <= 3
drivers/mailbox/mailbox-th1520.c:548 th1520_mbox_resume_noirq() error: buffer overflow 'ctx->intr_mask' 3 <= 3

drivers/mailbox/mailbox-th1520.c
    525 static int __maybe_unused th1520_mbox_suspend_noirq(struct device *dev)
    526 {
    527         struct th1520_mbox_priv *priv = dev_get_drvdata(dev);
    528         struct th1520_mbox_context *ctx = priv->ctx;
    529         u32 i;
    530         /*
    531          * ONLY interrupt mask bit should be stored and restores.
    532          * INFO data all assumed to be lost.
    533          */
    534         for (i = 0; i < TH_1520_MBOX_CHANS; i++) {
--> 535                 ctx->intr_mask[i] =

The ctx->intr_mask[] array has TH_1520_MBOX_CHANS - 1 elements so this is
memory corruption.

    536                         ioread32(priv->local_icu[i] + TH_1520_MBOX_MASK);
    537         }
    538         return 0;
    539 }

regards,
dan carpenter