e01d48c699
The out-of-bounds access is reported by UBSAN:
[ 0.000000] UBSAN: array-index-out-of-bounds in ../arch/riscv/kernel/vendor_extensions.c:41:66
[ 0.000000] index -1 is out of range for type 'riscv_isavendorinfo [32]'
[ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.11.0-rc2ubuntu-defconfig #2
[ 0.000000] Hardware name: riscv-virtio,qemu (DT)
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff94e078ba>] dump_backtrace+0x32/0x40
[ 0.000000] [<ffffffff95c83c1a>] show_stack+0x38/0x44
[ 0.000000] [<ffffffff95c94614>] dump_stack_lvl+0x70/0x9c
[ 0.000000] [<ffffffff95c94658>] dump_stack+0x18/0x20
[ 0.000000] [<ffffffff95c8bbb2>] ubsan_epilogue+0x10/0x46
[ 0.000000] [<ffffffff95485a82>] __ubsan_handle_out_of_bounds+0x94/0x9c
[ 0.000000] [<ffffffff94e09442>] __riscv_isa_vendor_extension_available+0x90/0x92
[ 0.000000] [<ffffffff94e043b6>] riscv_cpufeature_patch_func+0xc4/0x148
[ 0.000000] [<ffffffff94e035f8>] _apply_alternatives+0x42/0x50
[ 0.000000] [<ffffffff95e04196>] apply_boot_alternatives+0x3c/0x100
[ 0.000000] [<ffffffff95e05b52>] setup_arch+0x85a/0x8bc
[ 0.000000] [<ffffffff95e00ca0>] start_kernel+0xa4/0xfb6
The dereferencing using cpu should actually not happen, so remove it.
Fixes: 23c996fc2b ("riscv: Extend cpufeature.c to detect vendor extensions")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240814192619.276794-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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 reStructuredText 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.