0091429095
Will reports that with CONFIG_EXPERT=y and CONFIG_HARDEN_BRANCH_PREDICTOR=n, the kernel dereferences a NULL pointer during boot: [ 2.384444] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 2.384461] pstate: 20400085 (nzCv daIf +PAN -UAO) [ 2.384472] pc : cpu_hyp_reinit+0x114/0x30c [ 2.384476] lr : cpu_hyp_reinit+0x80/0x30c [ 2.384529] Call trace: [ 2.384533] cpu_hyp_reinit+0x114/0x30c [ 2.384537] _kvm_arch_hardware_enable+0x30/0x54 [ 2.384541] flush_smp_call_function_queue+0xe4/0x154 [ 2.384544] generic_smp_call_function_single_interrupt+0x10/0x18 [ 2.384549] ipi_handler+0x170/0x2b0 [ 2.384555] handle_percpu_devid_fasteoi_ipi+0x120/0x1cc [ 2.384560] __handle_domain_irq+0x9c/0xf4 [ 2.384563] gic_handle_irq+0x6c/0xe4 [ 2.384566] el1_irq+0xf0/0x1c0 [ 2.384570] arch_cpu_idle+0x28/0x44 [ 2.384574] do_idle+0x100/0x2a8 [ 2.384577] cpu_startup_entry+0x20/0x24 [ 2.384581] secondary_start_kernel+0x1b0/0x1cc [ 2.384589] Code: b9469d08 7100011f 540003ad 52800208 (f9400108) [ 2.384600] ---[ end trace 266d08dbf96ff143 ]--- [ 2.385171] Kernel panic - not syncing: Fatal exception in interrupt In this configuration arm64_get_bp_hardening_data() returns NULL. Add a check in kvm_get_hyp_vector(). Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/linux-arm-kernel/20220408120041.GB27685@willie-the-truck/ Fixes: 26129ea2953b ("KVM: arm64: Add templates for BHB mitigation sequences") Cc: stable@vger.kernel.org # 5.4.x Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.