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

ACPI: fix NULL pointer dereference

Commit 71f642833284 ("ACPI: utils: Fix reference counting in
for_each_acpi_dev_match()") started doing "acpi_dev_put()" on a pointer
that was possibly NULL.  That fails miserably, because that helper
inline function is not set up to handle that case.

Just make acpi_dev_put() silently accept a NULL pointer, rather than
calling down to put_device() with an invalid offset off that NULL
pointer.

kernel.org https://git.kernel.org/stable/c/38f54217b423c0101d03a00feec6fb8ec608b12e [No types assigned]

kernel.org https://git.kernel.org/stable/c/cae3fa3d8165761f3000f523b11cfa1cd35206bc [No types assigned]

kernel.org https://git.kernel.org/stable/c/ccf23a0888077a25a0793a746c3941db2a7562e4 [No types assigned]

kernel.org https://git.kernel.org/stable/c/fc68f42aa737dc15e7665a4101d4168aadb8e4c4 [No types assigned]