kernel/git/stable/linux-stable.git/drivers/mailbox, branch linux-6.12.y

mailbox: pcc: Fix command timeout due to missed interrupt

2026-09-14T11:32:47+00:00

[ Upstream commit 3360b088175dc5d5c9166685836158470d00571e ] PCC command execution can time out when a fast platform completes a transaction and signals the platform interrupt before pcc_send_data() marks the channel as in use. For shared platform interrupts, the type 3 handler uses chan_in_use to decide whether the interrupt belongs to the channel. If it observes false, it ignores the completion and the caller waits until timeout. Publish chan_in_use before ringing the doorbell. Use WRITE_ONCE() for the lockless flag updates and READ_ONCE() in the interrupt handler. The following ordered I/O accessor orders the flag store before the platform is notified. Clear chan_in_use if ringing the doorbell fails. Otherwise, leave it set until the interrupt handler completes the transaction, clearing it before the mailbox core can submit another transfer. Fixes: 3db174e478cb ("mailbox: pcc: Support shared interrupt for multiple subspaces") Signed-off-by: Huisong Li Signed-off-by: Sudeep Holla Tested-by: Adam Young Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin

Revert "mailbox/pcc: support mailbox management of the shared buffer"

2026-09-14T11:32:47+00:00

[ Upstream commit f82c3e62b6b8c31d8c56415bf38658f306fda4cb ] This reverts commit 5378bdf6a611a32500fccf13d14156f219bb0c85. Commit 5378bdf6a611 ("mailbox/pcc: support mailbox management of the shared buffer") attempted to introduce generic helpers for managing the PCC shared memory, but it largely duplicates functionality already provided by the mailbox core and leaves gaps: 1. TX preparation: The mailbox framework already supports this via ->tx_prepare callback for mailbox clients. The patch adds pcc_write_to_buffer() and expects clients to toggle pchan->chan.manage_writes, but no drivers set manage_writes, so pcc_write_to_buffer() has no users. 2. RX handling: Data reception is already delivered through mbox_chan_received_data() and client ->rx_callback. The patch adds an optional pchan->chan.rx_alloc, which again has no users and duplicates the existing path. 3. Completion handling: While adding last_tx_done is directionally useful, the implementation only covers Type 3/4 and fails to handle the absence of a command_complete register, so it is incomplete for other types. Given the duplication and incomplete coverage, revert this change. Any new requirements should be addressed in focused follow-ups rather than bundling multiple behavioral changes together. Fixes: 5378bdf6a611 ("mailbox/pcc: support mailbox management of the shared buffer") Signed-off-by: Sudeep Holla Signed-off-by: Jassi Brar Stable-dep-of: 3360b088175d ("mailbox: pcc: Fix command timeout due to missed interrupt") Signed-off-by: Sasha Levin

mailbox/pcc: support mailbox management of the shared buffer

2026-09-14T11:32:47+00:00

[ Upstream commit 5378bdf6a611a32500fccf13d14156f219bb0c85 ] Define a new, optional, callback that allows the driver to specify how the return data buffer is allocated. If that callback is set, mailbox/pcc.c is now responsible for reading from and writing to the PCC shared buffer. This also allows for proper checks of the Commnand complete flag between the PCC sender and receiver. For Type 4 channels, initialize the command complete flag prior to accepting messages. Since the mailbox does not know what memory allocation scheme to use for response messages, the client now has an optional callback that allows it to allocate the buffer for a response message. When an outbound message is written to the buffer, the mailbox checks for the flag indicating the client wants an tx complete notification via IRQ. Upon receipt of the interrupt It will pair it with the outgoing message. The expected use is to free the kernel memory buffer for the previous outgoing message. Signed-off-by: Adam Young Signed-off-by: Jassi Brar Stable-dep-of: 3360b088175d ("mailbox: pcc: Fix command timeout due to missed interrupt") Signed-off-by: Sasha Levin

mailbox: pcc: Always map the shared memory communication address

2026-09-14T11:32:47+00:00

[ Upstream commit fa362ffafa51b08cf8e2fcca38e056332f6b9b05 ] Currently the shared memory communication address was mapped by the mailbox client drivers leading to all sorts of inconsistencies. It also has resulted in the inconsistent attributes used while mapping the shared memory regions. In order to remove/eliminate any issues, let us ensures the shared memory address is always mapped and unmapped when the PCC channels are requested and release. We need to map them as the ACPI PCCT associates these shared memory with each channel subspace and may need use the status or the flags in the headers of those shared memory communication address regions to manage the transport/channel. Note, until all the drivers using PCC start using this mapped shmem, there might be double mapping of the shared memory address. This shouldn't have any impact on existing mbox client drivers. Since there are no users of pcc_chan_ioremap() and also it is mapped by default, we can stop exporting it and merge the functionality into pcc_mbox_request_channel(). Acked-by: Huisong Li Tested-by: Huisong Li Tested-by: Adam Young Signed-off-by: Sudeep Holla Signed-off-by: Jassi Brar Stable-dep-of: 3360b088175d ("mailbox: pcc: Fix command timeout due to missed interrupt") Signed-off-by: Sasha Levin

mailbox: rockchip: disable pclk on probe failure and unbind

2026-09-14T11:32:46+00:00

[ Upstream commit ded48fcbdc1e3ed1dc8e1974b7fe9639fcea6dd6 ] rockchip_mbox_probe() enables the peripheral clock and then keeps going. None of the later failure paths - platform_get_irq(), devm_request_threaded_irq() and devm_mbox_controller_register() - disables it again. The driver has no remove callback either, so the clock also stays prepared and enabled once the device is unbound, and its enable count keeps growing over bind/unbind cycles. Use devm_clk_get_enabled() to tie disabling and unpreparing the clock to the device lifetime. It is registered before the interrupts and the mailbox controller, so devres releases it after both are gone. While rewriting the error path, switch it to dev_err_probe() so that a deferred probe is not reported as an error. Fixes: f70ed3b5dc8b ("mailbox: rockchip: Add Rockchip mailbox driver") Signed-off-by: Linmao Li Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin

mailbox: qcom-cpucp: handle NULL data in send_data callback

2026-09-14T11:32:46+00:00

[ Upstream commit fc4f2f99530298a1739226947aa76525142d421d ] mailbox_clear_channel() calls mbox_send_message() with NULL data to notify the remote side that the RX channel has been cleared. qcom_cpucp_mbox_send_data() blindly dereferenced the data pointer, causing a NULL pointer dereference kernel panic when invoked from this path under PREEMPT_RT. Add an explicit NULL check and return early without writing to the TX register, which is the correct behaviour for a channel-clear notification. Fixes: 0e2a9a03106c ("mailbox: Add support for QTI CPUCP mailbox controller") Signed-off-by: Jia Yang Reviewed-by: Dmitry Baryshkov Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin

mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler

2026-09-14T11:32:46+00:00

[ Upstream commit 3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c ] qcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding chan->lock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an rt_spinlock (rtmutex-based), which tracks ownership and can sleep. The callback chain triggered by mbox_chan_received_data() eventually reaches mailbox_clear_channel() -> mbox_send_message() -> add_to_rbuf(), which attempts to re-acquire the same chan->lock. Since rtmutex detects the re-entrant lock attempt by the same owner, the thread blocks waiting for a lock it already holds, causing a permanent deadlock. This deadlock manifests as 'irq/N-apss_cpucp_mbox' stuck in D state with the following call trace: rt_spin_lock -> mbox_send_message -> mailbox_clear_channel -> scmi_rx_callback -> mbox_chan_received_data [<- held chan->lock here] Fix by saving chan->cl locally and clearing the HW interrupt register inside the lock, then invoking mbox_chan_received_data() after releasing the lock. This preserves the mutual exclusion for chan->cl access while avoiding the lock re-entrancy that causes the PREEMPT_RT deadlock. Fixes: 0e2a9a03106c ("mailbox: Add support for QTI CPUCP mailbox controller") Signed-off-by: Jia Yang Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin

mailbox: qcom-ipcc: fix duplicate channel allocation across holes

2026-09-07T15:18:11+00:00

commit 66c7bcad72430a02c860521031350b84b31ad9a8 upstream. The IPCC of_xlate() both scans for a free mailbox channel and checks for duplicate references to the same underlying IPCC channel. When a channel has been shutdown it might have left a hole in the channel list, which would terminate the search without considering duplicates later in the list. Continue the traversal of the channel list to detect and reject duplicates, while keeping track of the first free channel. Fixes: d6fbfdbc1274 ("mailbox: qcom-ipcc: Fix IPCC mbox channel exhaustion") Cc: stable@vger.kernel.org Signed-off-by: Anup Vishwakarma Signed-off-by: Jassi Brar Signed-off-by: Greg Kroah-Hartman

mailbox: imx: Forward the timeout/ error in imx_mu_generic_tx()

2026-07-24T14:11:12+00:00

[ Upstream commit 82ef9a635d7130ca27ec9dd88c16afc39c83a4e8 ] imx_mu_generic_tx() for the IMX_MU_TYPE_TXDB_V2 type polls on a register which may timeout and is recognized as an error. This error is siltently dropped and not dropped to the caller. Forward the error to the caller. Fixes: b5ef17917f3a7 ("mailbox: imx: fix TXDB_V2 channel race condition") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin

mailbox: mtk-adsp: fix UAF during device teardown

2026-07-24T14:11:05+00:00

[ Upstream commit b57d1a40bc43258372fa1f4d39305e093947a262 ] When the SOF audio driver fails to initialize (e.g. firmware boot timeout), its devres unwind frees the snd_sof_dev object that the mailbox client (mtk-adsp-ipc) reaches via chan->cl->rx_callback. The mtk-adsp-mailbox shutdown clears the mailbox command registers but leaves the IRQ line unmasked, so a late interrupt can still queue a threaded handler after mbox_free_channel() had cleared chan->cl, and mbox_chan_received_data() would then trigger UAF: BUG: KASAN: slab-use-after-free in sof_ipc3_validate_fw_version sof_ipc3_validate_fw_version sof_ipc3_do_rx_work sof_ipc3_rx_msg mt8196_dsp_handle_request mtk_adsp_ipc_recv mbox_chan_received_data mtk_adsp_mbox_isr irq_thread_fn Freed by task ...: kfree devres_release_all really_probe ... (sof-audio-of-mt8196 probe failure) The crash was observed roughly three seconds after the failed probe. disable_irq() in shutdown and enable_irq() in startup. disable_irq() also waits for any in-flight interrupts, so by the time mbox_free_channel() proceeds to clear chan->cl no rx_callback can run. In addition, request the IRQ with IRQF_NO_AUTOEN so it stays masked between probe and the first client bind — otherwise an early interrupt can crash on chan->cl == NULL in mbox_chan_received_data(). Fixes: af2dfa96c52d ("mailbox: mediatek: add support for adsp mailbox controller") Signed-off-by: Sergey Senozhatsky Reviewed-by: Tzung-Bi Shih Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin