Linux Kernel NULL Pointer Dereference Vulnerability in NVMe PCI Component

A vulnerability in the Linux kernel's NVMe PCI component can lead to a NULL pointer dereference. This issue arises in the 'nvme_alloc_admin_tags' function, where the 'admin_q' variable may be set to an error state (typically due to insufficient memory) if the 'blk_mq_init_queue' call fails. When this error is propagated up the stack, it can trigger the 'nvme_remove_dead_ctrl' function, which checks only if the 'admin_q' is non-NULL. This oversight allows the function to attempt to quiesce a queue that doesn't exist, resulting in a bad or NULL pointer dereference.

Impact

Exploitation of this vulnerability causes a NULL pointer dereference, leading to a crash or undefined behavior in the kernel.