CVE-2026-93261locking/lockdep: Fix NULL pointer dereference in __lock_set_class()

Official description

In the Linux kernel, the following vulnerability has been resolved: locking/lockdep: Fix NULL pointer dereference in __lock_set_class() register_lock_class() can return NULL when the lock class pool is exhausted, graph_lock() fails, or key validation fails. However, __lock_set_class() uses the return value directly in pointer arithmetic without a NULL check: class = register_lock_class(lock, subclass, 0); hlock->class_idx = class - lock_classes; If class is NULL, this computes a wild offset that corrupts hlock->class_idx. The subsequent reacquire_held_locks() call will invoke hlock_class() with this corrupted index, leading to a NULL or out-of-bounds pointer dereference. Add the missing NULL check, consistent with how __lock_acquire() already handles this case at the same call site.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/f6093ff67ea6e347574819ed23e96e0f82a25ffc
• https://git.kernel.org/stable/c/59a5c7dd331a3dab48100e1ef8e9bb4f9132a2b2
• https://git.kernel.org/stable/c/f56e54fd24f05e9de528fcb77f6084f80c8066ce
• https://git.kernel.org/stable/c/5c3bff6cf26e6a54fbf8b893a879c32824d2d50d
• https://git.kernel.org/stable/c/b2113dcd8238bf00ce37a34e67b29cf31d32a545
• https://git.kernel.org/stable/c/e7c69c6695d84220847cca62a45e879e71e79e9d
• https://git.kernel.org/stable/c/9be10f49dfc2e4b472b3a5f346483b67374774b8
• https://git.kernel.org/stable/c/7577e00b9ab506202b9f1a33de3cc8cc6413a4db