07ffdf0d98
commit a194c33f45f83068ef13bf1d16e26d4ca3ecc098 upstream. Will reported a UBSAN warning: UBSAN: null-ptr-deref in arch/arm64/kernel/smp.c:596:6 member access within null pointer of type 'struct acpi_madt_generic_interrupt' CPU: 0 PID: 0 Comm: swapper Not tainted 5.7.0-rc6-00124-g96bc42ff0a82 #1 Call trace: dump_backtrace+0x0/0x384 show_stack+0x28/0x38 dump_stack+0xec/0x174 handle_null_ptr_deref+0x134/0x174 __ubsan_handle_type_mismatch_v1+0x84/0xa4 acpi_parse_gic_cpu_interface+0x60/0xe8 acpi_parse_entries_array+0x288/0x498 acpi_table_parse_entries_array+0x178/0x1b4 acpi_table_parse_madt+0xa4/0x110 acpi_parse_and_init_cpus+0x38/0x100 smp_init_cpus+0x74/0x258 setup_arch+0x350/0x3ec start_kernel+0x98/0x6f4 This is from the use of the ACPI_OFFSET in arch/arm64/include/asm/acpi.h. Replace its use with offsetof from include/linux/stddef.h which should implement the same logic using __builtin_offsetof, so that UBSAN wont warn. Reported-by: Will Deacon <will@kernel.org> Suggested-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/20200521100952.GA5360@willie-the-truck/ Link: https://lore.kernel.org/r/20200608203818.189423-1-ndesaulniers@google.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.