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Input: edt-ft5x06 - fix use-after-free in debugfs teardown

The commit 68743c500c6e ("Input: edt-ft5x06 - use per-client debugfs
directory") removed the manual debugfs teardown, relying on the I2C core
to handle it. However, this creates a window where debugfs files are
still accessible after edt_ft5x06_ts_teardown_debugfs() frees
tsdata->raw_buffer.

To prevent a use-after-free, protect the freeing of raw_buffer with the
device mutex and set raw_buffer to NULL. The debugfs read function
already checks if raw_buffer is NULL under the same mutex, so this
safely avoids the use-after-free.

Fixes: 68743c500c6e ("Input: edt-ft5x06 - use per-client debugfs directory")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/adnJicDh-bTUaWXP@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Dmitry Torokhov f5f9e070 875115b8

+3
+3
drivers/input/touchscreen/edt-ft5x06.c
··· 804 804 805 805 static void edt_ft5x06_ts_teardown_debugfs(struct edt_ft5x06_ts_data *tsdata) 806 806 { 807 + guard(mutex)(&tsdata->mutex); 808 + 807 809 kfree(tsdata->raw_buffer); 810 + tsdata->raw_buffer = NULL; 808 811 } 809 812 810 813 #else