NULL pointer dereference in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: ice: fix NULL pointer dereference in ice_reset_all_vfs() ice_reset_all_vfs() ignores the return value of ice_vf_rebuild_vsi(). When the VSI rebuild fails (e.g. during NVM firmware update via nvmupdate64e), ice_vsi_rebuild() tears down the VSI on its error path, leaving txq_map and rxq_map as NULL. The subsequent unconditional call to ice_vf_post_vsi_rebuild() leads to a NULL pointer dereference in ice_ena_vf_q_mappings() when it accesses vsi->txq_map[0]. The single-VF reset path in ice_reset_vf() already handles this correctly by checking the return value of ice_vf_reconfig_vsi() and skipping ice_vf_post_vsi_rebuild() on failure. Apply the same pattern to ice_reset_all_vfs(): check the return value of ice_vf_rebuild_vsi() and skip ice_vf_post_vsi_rebuild() and ice_eswitch_attach_vf() on failure. The VF is left safely disabled (ICE_VF_STATE_INIT not set, VFGEN_RSTAT not set to VFACTIVE) and can be recovered via a VFLR triggered by a PCI reset of the VF (sysfs reset or driver rebind). Note that this patch does not prevent the VF VSI rebuild from failing during NVM update — the underlying cause is firmware being in a transitional state while the EMP reset is processed, which can cause Admin Queue commands (ice_add_vsi, ice_cfg_vsi_lan) to fail. This patch only prevents the subsequent NULL pointer dereference that crashes the kernel when the rebuild does fail. crash> bt PID: 50795 TASK: ff34c9ee708dc680 CPU: 1 COMMAND: "kworker/u512:5" #0 [ff72159bcfe5bb50] machine_kexec at ffffffffaa8850ee #1 [ff72159bcfe5bba8] __crash_kexec at ffffffffaaa15fba #2 [ff72159bcfe5bc68] crash_kexec at ffffffffaaa16540 #3 [ff72159bcfe5bc70] oops_end at ffffffffaa837eda #4 [ff72159bcfe5bc90] page_fault_oops at ffffffffaa893997 #5 [ff72159bcfe5bce8] exc_page_fault at ffffffffab528595 #6 [ff72159bcfe5bd10] asm_exc_page_fault at ffffffffab600bb2 [exception RIP: ice_ena_vf_q_mappings+0x79] RIP: ffffffffc0a85b29 RSP: ff72159bcfe5bdc8 RFLAGS: 00010206 RAX: 00000000000f0000 RBX: ff34c9efc9c00000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000010 RDI: ff34c9efc9c00000 RBP: ff34c9efc27d4828 R8: 0000000000000093 R9: 0000000000000040 R10: ff34c9efc27d4828 R11: 0000000000000040 R12: 0000000000100000 R13: 0000000000000010 R14: R15: ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ff72159bcfe5bdf8] ice_sriov_post_vsi_rebuild at ffffffffc0a85e2e [ice] #8 [ff72159bcfe5be08] ice_reset_all_vfs at ffffffffc0a920b4 [ice] #9 [ff72159bcfe5be48] ice_service_task at ffffffffc0a31519 [ice] #10 [ff72159bcfe5be88] process_one_work at ffffffffaa93dca4 #11 [ff72159bcfe5bec8] worker_thread at ffffffffaa93e9de #12 [ff72159bcfe5bf18] kthread at ffffffffaa946663 #13 [ff72159bcfe5bf50] ret_from_fork at ffffffffaa8086b9 The panic occurs attempting to dereference the NULL pointer in RDX at ice_sriov.c:294, which loads vsi->txq_map (offset 0x4b8 in ice_vsi). The faulting VSI is an allocated slab object but not fully initialized after a failed ice_vsi_rebuild(): crash> struct ice_vsi 0xff34c9efc27d4828 netdev = 0x0, rx_rings = 0x0, tx_rings = 0x0, q_vectors = 0x0, txq_map = 0x0, rxq_map = 0x0, alloc_txq = 0x10, num_txq = 0x10, alloc_rxq = 0x10, num_rxq = 0x10, The nvmupdate64e process was performing NVM firmware update: crash> bt 0xff34c9edd1a30000 PID: 49858 TASK: ff34c9edd1a30000 CPU: 1 COMMAND: "nvmupdate64e" #0 [ff72159bcd617618] __schedule at ffffffffab5333f8 #4 [ff72159bcd617750] ice_sq_send_cmd at ffffffffc0a35347 [ice] #5 [ff72159bcd6177a8] ice_sq_send_cmd_retry at ffffffffc0a35b47 [ice] #6 [ff72159bcd617810] ice_aq_send_cmd at ffffffffc0a38018 [ice] #7 [ff72159bcd617848] ice_aq_read_nvm at ffffffffc0a40254 [ice] #8 ---truncated---