From: Aleksandr Nogikh <nogikh@google.com>

Commit 16637fea001a ("usb-storage: alauda: Check whether the media is
initialized") added a `media_initialized` boolean to `struct alauda_info`
to prevent `uzonesize` from remaining 0 on initialization failure. However,
`media_initialized` is shared between both LUNs (XD and SM media ports)
supported by the Alauda driver.

When the kernel probes LUN 0, it successfully initializes the media and
sets `media_initialized = true`. When it subsequently probes LUN 1,
`alauda_check_media()` sees that `media_initialized` is already true, skips
the initialization for LUN 1, and leaves its `uzonesize` as 0. Later, when
a read/write command is issued to LUN 1, the driver attempts to divide by
`uzonesize` in `alauda_read_data()`, resulting in a divide-by-zero
exception:

Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 5849 Comm: usb-storage Not tainted
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:954 [inline]
RIP: 0010:alauda_transport+0xbd6/0x43a0 drivers/usb/storage/alauda.c:1187
Call Trace:
 <TASK>
 usb_stor_invoke_transport+0x115/0x1a40 drivers/usb/storage/transport.c:611
 usb_stor_control_thread+0x44c/0x8f0 drivers/usb/storage/usb.c:462
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

To fix this, move the `media_initialized` boolean from `struct alauda_info`
to `struct alauda_media_info` so that each LUN tracks its initialization
state independently. Additionally, explicitly set `media_initialized =
false` when no media is present or before calling `alauda_init_media()`.
This ensures that if initialization fails halfway through, the driver won't
accidentally trust stale data from a previously inserted card.

Fixes: 16637fea001a ("usb-storage: alauda: Check whether the media is initialized")
Assisted-by: Gemini:gemini-3.7-flash Gemini:gemini-3.1-pro-preview syzbot
Reported-by: syzbot+dc208a8cf8d37cf3e5ac@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=dc208a8cf8d37cf3e5ac
Link: https://syzkaller.appspot.com/ai_job?id=87935d94-4387-493a-8061-bcb7752c517c
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>

---
diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 691fe4700..807492f75 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -96,6 +96,8 @@ struct alauda_media_info {
 
 	u16 **lba_to_pba;		/* logical to physical block map */
 	u16 **pba_to_lba;		/* physical to logical block map */
+
+	bool media_initialized;
 };
 
 struct alauda_info {
@@ -105,8 +107,6 @@ struct alauda_info {
 	unsigned char sense_key;
 	unsigned long sense_asc;	/* additional sense code */
 	unsigned long sense_ascq;	/* additional sense code qualifier */
-
-	bool media_initialized;
 };
 
 #define short_pack(lsb,msb) ( ((u16)(lsb)) | ( ((u16)(msb))<<8 ) )
@@ -471,6 +471,7 @@ static int alauda_check_media(struct us_data *us)
 		|| ((status[1] & 0x01) == 0)) {
 		usb_stor_dbg(us, "No media, or door open\n");
 		alauda_free_maps(&MEDIA_INFO(us));
+		MEDIA_INFO(us).media_initialized = false;
 		info->sense_key = 0x02;
 		info->sense_asc = 0x3A;
 		info->sense_ascq = 0x00;
@@ -478,12 +479,13 @@ static int alauda_check_media(struct us_data *us)
 	}
 
 	/* Check for media change */
-	if (status[0] & 0x08 || !info->media_initialized) {
+	if (status[0] & 0x08 || !MEDIA_INFO(us).media_initialized) {
 		usb_stor_dbg(us, "Media change detected\n");
 		alauda_free_maps(&MEDIA_INFO(us));
+		MEDIA_INFO(us).media_initialized = false;
 		rc = alauda_init_media(us);
 		if (rc == USB_STOR_TRANSPORT_GOOD)
-			info->media_initialized = true;
+			MEDIA_INFO(us).media_initialized = true;
 		info->sense_key = UNIT_ATTENTION;
 		info->sense_asc = 0x28;
 		info->sense_ascq = 0x00;


base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f
-- 
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