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

tracing: Fix potential double free in create_var_ref()

In create_var_ref(), init_var_ref() is called to initialize the fields
of variable ref_field, which is allocated in the previous function call
to create_hist_field(). Function init_var_ref() allocates the
corresponding fields such as ref_field->system, but frees these fields
when the function encounters an error. The caller later calls
destroy_hist_field() to conduct error handling, which frees the fields
and the variable itself. This results in double free of the fields which
are already freed in the previous function.

Fix this by storing NULL to the corresponding fields when they are freed
in init_var_ref().

https://git.kernel.org/stable/c/058cb6d86b9789377216c936506b346aaa1eb581

https://git.kernel.org/stable/c/37443b3508b8cce6832f8d25cb4550b2f7801f50

https://git.kernel.org/stable/c/4fdfb15e08598711dbf50daf56a33965232daf0e

https://git.kernel.org/stable/c/99696a2592bca641eb88cc9a80c90e591afebd0f

https://git.kernel.org/stable/c/bd83ff3bbfb003832481c9bff999d12385f396ae

https://git.kernel.org/stable/c/c27f744ceefadc7bbeb14233b6abc150ced617d2

https://git.kernel.org/stable/c/f8b383f83cb573152c577eca1ef101e89995b72a