[openwrt/openwrt] ltq-adsl-mei: check status register before reading mailbox messages
LEDE Commits
lede-commits at lists.infradead.org
Thu Jul 17 12:12:08 PDT 2025
hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/6889ea7b9a466b73f59fad9c6ae942728b907200
commit 6889ea7b9a466b73f59fad9c6ae942728b907200
Author: Jan Hoffmann <jan at 3e8.eu>
AuthorDate: Fri Jul 11 20:31:29 2025 +0200
ltq-adsl-mei: check status register before reading mailbox messages
The interrupt handler reads from the mailbox if no other reason for the
interrupt is known. If a spurious interrupt is received just after a
mailbox message has been sent, this means that the response to the
previous message is read again and returned by DSL_BSP_SendCMV instead
of the actual response.
To fix this, check the status register before reading from the mailbox
in the interrupt handler.
Tested on Fritzbox 7320. Without this change, there is occasionally a
kernel panic due to an out-of-bounds memory access in the ltq-adsl
driver (in DSL_DRV_DEV_G997_SnrAllocationNscGet), as a result of an
incorrect value returned by DSL_DRV_DANUBE_CmvRead. This is reproducible
by calling "dsl_cpe_pipe.sh g997dsnrg 1 1" multiple times.
Signed-off-by: Jan Hoffmann <jan at 3e8.eu>
Link: https://github.com/openwrt/openwrt/pull/19385
Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
package/kernel/lantiq/ltq-adsl-mei/src/drv_mei_cpe.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/package/kernel/lantiq/ltq-adsl-mei/src/drv_mei_cpe.c b/package/kernel/lantiq/ltq-adsl-mei/src/drv_mei_cpe.c
index 2680e1fa86..c0fb66c5e3 100644
--- a/package/kernel/lantiq/ltq-adsl-mei/src/drv_mei_cpe.c
+++ b/package/kernel/lantiq/ltq-adsl-mei/src/drv_mei_cpe.c
@@ -1787,6 +1787,7 @@ extern void ifx_usb_enable_afe_oc(void);
*/
static irqreturn_t IFX_MEI_IrqHandle (int int1, void *void0)
{
+ u32 stat;
u32 scratch;
DSL_DEV_Device_t *pDev = (DSL_DEV_Device_t *) void0;
#if defined(CONFIG_LTQ_MEI_FW_LOOPBACK) && defined(DFE_PING_TEST)
@@ -1820,6 +1821,12 @@ static irqreturn_t IFX_MEI_IrqHandle (int int1, void *void0)
if (dsl_bsp_event_callback[event].function)
(*dsl_bsp_event_callback[event].function)(pDev, event, dsl_bsp_event_callback[event].pData);
} else { // normal message
+ IFX_MEI_LongWordReadOffset (pDev, (u32) ME_ARC2ME_STAT, &stat);
+ if (!(stat & ARC_TO_MEI_MSGAV)) {
+ // status register indicates there is no message
+ return IRQ_NONE;
+ }
+
IFX_MEI_MailboxRead (pDev, DSL_DEV_PRIVATE(pDev)->CMV_RxMsg, MSG_LENGTH);
if (DSL_DEV_PRIVATE(pDev)-> cmv_waiting == 1) {
DSL_DEV_PRIVATE(pDev)-> arcmsgav = 1;
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