mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-06 02:50:49 +09:00
19ab500edb
Jan reported that LTP mmap03 was getting stuck in a page fault loop after commitc46241a370("powerpc/pkeys: Check vma before returning key fault error to the user"), as well as a minimised reproducer: #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> int main(int ac, char **av) { int page_sz = getpagesize(); int fildes; char *addr; fildes = open("tempfile", O_WRONLY | O_CREAT, 0666); write(fildes, &fildes, sizeof(fildes)); close(fildes); fildes = open("tempfile", O_RDONLY); unlink("tempfile"); addr = mmap(0, page_sz, PROT_EXEC, MAP_FILE | MAP_PRIVATE, fildes, 0); printf("%d\n", *addr); return 0; } And noticed that access_pkey_error() in page fault handler now always seem to return false: __do_page_fault access_pkey_error(is_pkey: 1, is_exec: 0, is_write: 0) arch_vma_access_permitted pkey_access_permitted if (!is_pkey_enabled(pkey)) return true return false pkey_access_permitted() should not check if the pkey is available in UAMOR (using is_pkey_enabled()). The kernel needs to do that check only when allocating keys. This also makes sure the execute_only_key which is marked as non-manageable via UAMOR is handled correctly in pkey_access_permitted(), and fixes the bug. Fixes:c46241a370("powerpc/pkeys: Check vma before returning key fault error to the user") Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [mpe: Include bug report details etc. in the change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200627070147.297535-1-aneesh.kumar@linux.ibm.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 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.