]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
usb: typec: displayport: Fix potential deadlock
authorAndrei Kuchynski <akuchynski@chromium.org>
Tue, 24 Jun 2025 13:32:46 +0000 (13:32 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 10 Jul 2025 13:59:53 +0000 (15:59 +0200)
commit76cf1f33e7319fe74c94ac92f9814094ee8cc84b
treee8dcfe0fa17dcd1b72b455aaaaf5daf80b1309d0
parentfdc38ababdc8d07549dd9ee435265d42f5d0513d
usb: typec: displayport: Fix potential deadlock

commit 099cf1fbb8afc3771f408109f62bdec66f85160e upstream.

The deadlock can occur due to a recursive lock acquisition of
`cros_typec_altmode_data::mutex`.
The call chain is as follows:
1. cros_typec_altmode_work() acquires the mutex
2. typec_altmode_vdm() -> dp_altmode_vdm() ->
3. typec_altmode_exit() -> cros_typec_altmode_exit()
4. cros_typec_altmode_exit() attempts to acquire the mutex again

To prevent this, defer the `typec_altmode_exit()` call by scheduling
it rather than calling it directly from within the mutex-protected
context.

Cc: stable <stable@kernel.org>
Fixes: b4b38ffb38c9 ("usb: typec: displayport: Receive DP Status Update NAK request exit dp altmode")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250624133246.3936737-1-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/typec/altmodes/displayport.c