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When enabling both CONFIG_KFENCE and CONFIG_DEBUG_SG, I get the following backtraces when running LongArch kernels. [ 2.496257] kernel BUG at include/linux/scatterlist.h:187! ... [ 2.501925] Call Trace: [ 2.501950] [<9000000004ad59c4>] sg_init_one+0xac/0xc0 [ 2.502204] [<9000000004a438f8>] do_test_kpp+0x278/0x6e4 [ 2.502353] [<9000000004a43dd4>] alg_test_kpp+0x70/0xf4 [ 2.502494] [<9000000004a41b48>] alg_test+0x128/0x690 [ 2.502631] [<9000000004a3d898>] cryptomgr_test+0x20/0x40 [ 2.502775] [<90000000041b4508>] kthread+0x138/0x158 [ 2.502912] [<9000000004161c48>] ret_from_kernel_thread+0xc/0xa4 The backtrace is always similar but not exactly the same. It is always triggered from cryptomgr_test, but not always from the same test. Analysis shows that with CONFIG_KFENCE active, the address returned from kmalloc() and friends is not always below vm_map_base. It is allocated by kfence_alloc() which at least sometimes seems to get its memory from an address space above vm_map_base. This causes __virt_addr_valid() to return false for the affected objects. Let __virt_addr_valid() return 1 for kfence pool addresses, this make virt_addr_valid()/__virt_addr_valid() work with KFENCE. Reported-by: Guenter Roeck <linux@roeck-us.net> Suggested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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.