A reboot can crash the kernel if it overlaps with WLAN firmware crash recovery (SSR). The crash is a NULL pointer dereference in the MHI teardown path while freeing DMA-backed MHI contexts. Simplified trace: dma_free_attrs mhi_deinit_dev_ctxt [mhi] ath11k_pci_power_down [ath11k_pci] ath11k_pci_shutdown [ath11k_pci] device_shutdown kernel_restart On the host side, SSR is driven by the MHI RDDM callback, which queues reset_work to perform device recovery. reset_work power-cycles the device by calling ath11k_hif_power_down() followed by ath11k_hif_power_up(). The power-down phase deinitializes MHI and frees DMA resources. Shutdown/reboot runs fully asynchronously with this RDDM-driven SSR recovery flow. As a result, the shutdown path (ath11k_pci_shutdown() -> ath11k_pci_power_down()) can race with the SSR recovery sequence. Fix this by canceling SSR-related work items during PCI shutdown, marking the device as unregistering, and serializing the RDDM callback path that checks and queues reset_work. This ensures that no new SSR recovery work can be queued once teardown has started, and that any in-flight recovery work is fully synchronized before device power-down, preventing MHI teardown and DMA resource freeing from running more than once. Note: This issue only affects PCI/MHI-based devices. AHB-based ath11k devices do not queue reset_work in normal SSR flows. Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04866.5-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1 Fixes: 13da397f884d ("ath11k: add support for device recovery for QCA6390/WCN6855") Fixes: 5edbb148bc57 ("wifi: ath11k: Add firmware coredump collection support") Signed-off-by: Wei Zhang --- drivers/net/wireless/ath/ath11k/mhi.c | 4 +++- drivers/net/wireless/ath/ath11k/pci.c | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c index f994233df2bb..a6c9ff112c68 100644 --- a/drivers/net/wireless/ath/ath11k/mhi.c +++ b/drivers/net/wireless/ath/ath11k/mhi.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: BSD-3-Clause-Clear /* * Copyright (c) 2020 The Linux Foundation. All rights reserved. - * Copyright (c) 2021-2025 Qualcomm Innovation Center, Inc. All rights reserved. + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. */ #include @@ -282,8 +282,10 @@ static void ath11k_mhi_op_status_cb(struct mhi_controller *mhi_cntrl, break; } + spin_lock_bh(&ab->base_lock); if (!(test_bit(ATH11K_FLAG_UNREGISTERING, &ab->dev_flags))) queue_work(ab->workqueue_aux, &ab->reset_work); + spin_unlock_bh(&ab->base_lock); break; default: diff --git a/drivers/net/wireless/ath/ath11k/pci.c b/drivers/net/wireless/ath/ath11k/pci.c index 7114eca8810d..35bb9e7a63a2 100644 --- a/drivers/net/wireless/ath/ath11k/pci.c +++ b/drivers/net/wireless/ath/ath11k/pci.c @@ -1210,6 +1210,14 @@ static void ath11k_pci_shutdown(struct pci_dev *pdev) struct ath11k_pci *ab_pci = ath11k_pci_priv(ab); ath11k_pci_set_irq_affinity_hint(ab_pci, NULL); + + spin_lock_bh(&ab->base_lock); + set_bit(ATH11K_FLAG_UNREGISTERING, &ab->dev_flags); + spin_unlock_bh(&ab->base_lock); + + cancel_work_sync(&ab->reset_work); + cancel_work_sync(&ab->dump_work); + ath11k_pci_power_down(ab, false); } base-commit: 15551ababf6d4e857f2101366a0c3eaa86dd822c -- 2.34.1