# git rev-parse -q --verify 19ab500edb5d6020010caba48ce3b4ce4182ab63^{commit} 19ab500edb5d6020010caba48ce3b4ce4182ab63 already have revision, skipping fetch # git checkout -q -f -B kisskb 19ab500edb5d6020010caba48ce3b4ce4182ab63 # git clean -qxdf # < git log -1 # commit 19ab500edb5d6020010caba48ce3b4ce4182ab63 # Author: Aneesh Kumar K.V # Date: Sat Jun 27 12:31:46 2020 +0530 # # powerpc/mm/pkeys: Make pkey access check work on execute_only_key # # Jan reported that LTP mmap03 was getting stuck in a page fault loop # after commit c46241a370a6 ("powerpc/pkeys: Check vma before returning # key fault error to the user"), as well as a minimised reproducer: # # #include # #include # #include # #include # #include # # 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: c46241a370a6 ("powerpc/pkeys: Check vma before returning key fault error to the user") # Reported-by: Jan Stancek # Signed-off-by: Aneesh Kumar K.V # [mpe: Include bug report details etc. in the change log] # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20200627070147.297535-1-aneesh.kumar@linux.ibm.com # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 19ab500edb5d6020010caba48ce3b4ce4182ab63 # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powernv_defconfig+STRICT_RWX_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- powernv_defconfig # Added to kconfig CONFIG_RELOCATABLE=n # Added to kconfig CONFIG_STRICT_KERNEL_RWX=y # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powernv_defconfig+STRICT_RWX_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powernv_defconfig+STRICT_RWX_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig .config:3977:warning: override: reassigning to symbol RELOCATABLE # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_powernv_defconfig+STRICT_RWX_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- Completed OK # rm -rf /kisskb/build/powerpc-fixes_powernv_defconfig+STRICT_RWX_powerpc-gcc9 # Build took: 0:03:52.398092