[PATCH v4 3/5] mtd: rawnand: brcmnand: Fix crash during the panic_write

[William Zhang]

When executing a NAND command within the panic write path, wait for any
pending command instead of calling BUG_ON to avoid crashing while
already crashing.

Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
Signed-off-by: William Zhang <william.zhang@xxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
Reviewed-by: Kursad Oney <kursad.oney@xxxxxxxxxxxx>
Reviewed-by: Kamal Dasu <kamal.dasu@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx

---

Changes in v4:
- Update commit message
- Add cc stable tag

Changes in v3: None
Changes in v2: None

 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 9a373a10304d..b2c6396060db 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1608,7 +1608,17 @@ static void brcmnand_send_cmd(struct brcmnand_host *host, int cmd)
 
 	dev_dbg(ctrl->dev, "send native cmd %d addr 0x%llx\n", cmd, cmd_addr);
 
-	BUG_ON(ctrl->cmd_pending != 0);
+	/*
+	 * If we came here through _panic_write and there is a pending
+	 * command, try to wait for it. If it times out, rather than
+	 * hitting BUG_ON, just return so we don't crash while crashing.
+	 */
+	if (oops_in_progress) {
+		if (ctrl->cmd_pending &&
+			bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0))
+			return;
+	} else
+		BUG_ON(ctrl->cmd_pending != 0);
 	ctrl->cmd_pending = cmd;
 
 	ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0);
-- 
2.37.3

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