CVE-2025-38486

In the Linux kernel, the following vulnerability has been resolved:

soundwire: Revert "soundwire: qcom: Add set_channel_map api support"

This reverts commit 7796c97df6b1b2206681a07f3c80f6023a6593d5.

This patch broke Dragonboard 845c (sdm845). I see:

Unexpected kernel BRK exception at EL1
Internal error: BRK handler: 00000000f20003e8 [#1]  SMP
pc : qcom_swrm_set_channel_map+0x7c/0x80 [soundwire_qcom]
lr : snd_soc_dai_set_channel_map+0x34/0x78
Call trace:
 qcom_swrm_set_channel_map+0x7c/0x80 [soundwire_qcom] (P)
 sdm845_dai_init+0x18c/0x2e0 [snd_soc_sdm845]
 snd_soc_link_init+0x28/0x6c
 snd_soc_bind_card+0x5f4/0xb0c
 snd_soc_register_card+0x148/0x1a4
 devm_snd_soc_register_card+0x50/0xb0
 sdm845_snd_platform_probe+0x124/0x148 [snd_soc_sdm845]
 platform_probe+0x6c/0xd0
 really_probe+0xc0/0x2a4
 __driver_probe_device+0x7c/0x130
 driver_probe_device+0x40/0x118
 __device_attach_driver+0xc4/0x108
 bus_for_each_drv+0x8c/0xf0
 __device_attach+0xa4/0x198
 device_initial_probe+0x18/0x28
 bus_probe_device+0xb8/0xbc
 deferred_probe_work_func+0xac/0xfc
 process_one_work+0x244/0x658
 worker_thread+0x1b4/0x360
 kthread+0x148/0x228
 ret_from_fork+0x10/0x20
Kernel panic - not syncing: BRK handler: Fatal exception

Dan has also reported following issues with the original patch https://lore.kernel.org/all/33fe8fe7-719a-405a-9ed2-d9f816ce1d57@sabinyo.mountain/

Bug #1: The zeroeth element of ctrl->pconfig[] is supposed to be unused. We start counting at 1. However this code sets ctrl->pconfig[0].ch_mask = 128.

Bug #2: There are SLIM_MAX_TX_PORTS (16) elements in tx_ch[] array but only QCOM_SDW_MAX_PORTS + 1 (15) in the ctrl->pconfig[] array so it corrupts memory like Yongqin Liu pointed out.

Bug 3: Like Jie Gan pointed out, it erases all the tx information with the rx information.