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Andrei Kuchynski
07f8aaffee
[ Upstream commit7aa7d4bf9d] A synchronization issue exists during port unregistration where pending partner work items can race against workqueue destruction, leading to use-after-free conditions: cros_ec_ucsi cros_ec_ucsi.3.auto: error -ETIMEDOUT: PPM init failed BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:__queue_work+0x83/0x4a0 Call Trace: <IRQ> __cfi_delayed_work_timer_fn+0x10/0x10 run_timer_softirq+0x3b6/0xbd0 sched_clock_cpu+0xc/0x110 irq_exit_rcu+0x18d/0x330 fred_sysvec_apic_timer_interrupt+0x5e/0x80 Fix this by ensuring strict ordering and proper serialization during teardown: 1. Move ucsi_unregister_partner() to the beginning of the teardown sequence and protect it under the connector mutex lock. 2. Ensure all pending partner tasks are explicitly flushed and finished before the workqueue is destroyed. 3. Switch from mod_delayed_work() to a cancel_delayed_work() and queue_delayed_work() sequence. This guarantees that items currently marked as pending won't be scheduled an additional time, preventing a double release of resources which leads to the following crash: Oops: general protection fault, probably for non-canonical address 0xdead000000000122: 0000 [#1] SMP NOPTI Workqueue: cros_ec_ucsi.3.auto-con2 ucsi_poll_worker RIP: 0010:ucsi_poll_worker+0x65/0x1e0 Call Trace: <TASK> process_scheduled_works+0x218/0x6d0 worker_thread+0x188/0x3f0 __cfi_worker_thread+0x10/0x10 kthread+0x226/0x2a0 To ensure these rules are applied identically across both the normal teardown and the ucsi_init() error paths, consolidate the cleanup logic into a new helper, ucsi_unregister_port(). Cc: stable <stable@kernel.org> Fixes:b9aa02ca39("usb: typec: ucsi: Add polling mechanism for partner tasks like alt mode checking") Fixes:b13abcb7dd("usb: typec: ucsi: Fix NULL pointer access") Fixes:fac4b8633f("usb: ucsi: Ensure connector delayed work items are flushed") Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org> Reviewed-by: Benson Leung <bleung@chromium.org> Link: https://patch.msgid.link/20260707141736.1635698-1-akuchynski@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.