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Revert "usb: typec: ucsi: Update UCSI structure to have message in and message out fields"

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This reverts commit 3e082978c3.

The new buffer management code has not been tested or reviewed properly
and breaks boot of machines like the Lenovo ThinkPad X13s:

    Unable to handle kernel NULL pointer dereference at virtual address
    0000000000000000

    CPU: 0 UID: 0 PID: 813 Comm: kworker/0:3 Not tainted 6.19.0-rc2 #26 PREEMPT
    Hardware name: LENOVO 21BYZ9SRUS/21BYZ9SRUS, BIOS N3HET87W (1.59 ) 12/05/2023
    Workqueue: events ucsi_handle_connector_change [typec_ucsi]

    Call trace:
     ucsi_sync_control_common+0xe4/0x1ec [typec_ucsi] (P)
     ucsi_run_command+0xcc/0x194 [typec_ucsi]
     ucsi_send_command_common+0x84/0x2a0 [typec_ucsi]
     ucsi_get_connector_status+0x48/0x78 [typec_ucsi]
     ucsi_handle_connector_change+0x5c/0x4f4 [typec_ucsi]
     process_one_work+0x208/0x60c
     worker_thread+0x244/0x388

The new code completely ignores concurrency so that the message length
can be updated while a transaction is ongoing. In the above case, the
length ends up being modified by another thread while processing an ack
so that the NULL cci pointer is dereferenced.

Fixing this will require designing a proper interface for managing these
transactions, something which most likely involves reverting most of the
offending commit anyway.

Revert the broken code to fix the regression and let Intel come up with
a properly tested implementation for a later kernel.

Fixes: 3e082978c3 ("usb: typec: ucsi: Update UCSI structure to have message in and message out fields")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20251222152204.2846-5-johan@kernel.org
This commit is contained in:
Johan Hovold 2025-12-22 16:22:04 +01:00 • committed by Greg Kroah-Hartman
commit e7a9f66001
8 changed files with 71 additions and 112 deletions
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