tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/sgx head: 5b8719504e3adf47646273781591ad439b3c3c7a commit: 5b8719504e3adf47646273781591ad439b3c3c7a [2/2] x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page() config: x86_64-randconfig-r004-20210318 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 6db3ab2903f42712f44000afb5aa467efbd25f35) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=5b... git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git git fetch --no-tags tip x86/sgx git checkout 5b8719504e3adf47646273781591ad439b3c3c7a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): if (page) ^~~~ arch/x86/kernel/cpu/sgx/main.c:502:22: note: uninitialized use occurs here nid = next_node_in(nid, sgx_numa_mask); ^~~ include/linux/nodemask.h:278:46: note: expanded from macro 'next_node_in' #define next_node_in(n, src) __next_node_in((n), &(src)) ^ arch/x86/kernel/cpu/sgx/main.c:496:3: note: remove the 'if' if its condition is always true if (page) ^~~~~~~~~ arch/x86/kernel/cpu/sgx/main.c:494:6: warning: variable 'nid' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (node_isset(nid_of_current, sgx_numa_mask)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/nodemask.h:152:36: note: expanded from macro 'node_isset' #define node_isset(node, nodemask) test_bit((node), (nodemask).bits) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kernel/cpu/sgx/main.c:502:22: note: uninitialized use occurs here nid = next_node_in(nid, sgx_numa_mask); ^~~ include/linux/nodemask.h:278:46: note: expanded from macro 'next_node_in' #define next_node_in(n, src) __next_node_in((n), &(src)) ^ arch/x86/kernel/cpu/sgx/main.c:494:2: note: remove the 'if' if its condition is always true if (node_isset(nid_of_current, sgx_numa_mask)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kernel/cpu/sgx/main.c:492:9: note: initialize the variable 'nid' to silence this warning int nid; ^ = 0 2 warnings generated. vim +496 arch/x86/kernel/cpu/sgx/main.c d2285493bef310 Jarkko Sakkinen 2020-11-13 477 d2285493bef310 Jarkko Sakkinen 2020-11-13 478 /** d2285493bef310 Jarkko Sakkinen 2020-11-13 479 * __sgx_alloc_epc_page() - Allocate an EPC page d2285493bef310 Jarkko Sakkinen 2020-11-13 480 * 5b8719504e3adf Jarkko Sakkinen 2021-03-18 481 * Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start 5b8719504e3adf Jarkko Sakkinen 2021-03-18 482 * from the NUMA node, where the caller is executing. d2285493bef310 Jarkko Sakkinen 2020-11-13 483 * d2285493bef310 Jarkko Sakkinen 2020-11-13 484 * Return: 5b8719504e3adf Jarkko Sakkinen 2021-03-18 485 * - an EPC page: A borrowed EPC pages were available. 5b8719504e3adf Jarkko Sakkinen 2021-03-18 486 * - NULL: Out of EPC pages. d2285493bef310 Jarkko Sakkinen 2020-11-13 487 */ d2285493bef310 Jarkko Sakkinen 2020-11-13 488 struct sgx_epc_page *__sgx_alloc_epc_page(void) d2285493bef310 Jarkko Sakkinen 2020-11-13 489 { d2285493bef310 Jarkko Sakkinen 2020-11-13 490 struct sgx_epc_page *page; 5b8719504e3adf Jarkko Sakkinen 2021-03-18 491 int nid_of_current = numa_node_id(); 5b8719504e3adf Jarkko Sakkinen 2021-03-18 492 int nid; d2285493bef310 Jarkko Sakkinen 2020-11-13 493 5b8719504e3adf Jarkko Sakkinen 2021-03-18 494 if (node_isset(nid_of_current, sgx_numa_mask)) { 5b8719504e3adf Jarkko Sakkinen 2021-03-18 495 page = __sgx_alloc_epc_page_from_node(nid_of_current); d2285493bef310 Jarkko Sakkinen 2020-11-13 @496 if (page) d2285493bef310 Jarkko Sakkinen 2020-11-13 497 return page; d2285493bef310 Jarkko Sakkinen 2020-11-13 498 } d2285493bef310 Jarkko Sakkinen 2020-11-13 499 5b8719504e3adf Jarkko Sakkinen 2021-03-18 500 /* Fall back to the non-local NUMA nodes: */ 5b8719504e3adf Jarkko Sakkinen 2021-03-18 501 while (true) { 5b8719504e3adf Jarkko Sakkinen 2021-03-18 502 nid = next_node_in(nid, sgx_numa_mask); 5b8719504e3adf Jarkko Sakkinen 2021-03-18 503 if (nid == nid_of_current) 5b8719504e3adf Jarkko Sakkinen 2021-03-18 504 break; 5b8719504e3adf Jarkko Sakkinen 2021-03-18 505 5b8719504e3adf Jarkko Sakkinen 2021-03-18 506 page = __sgx_alloc_epc_page_from_node(nid); 5b8719504e3adf Jarkko Sakkinen 2021-03-18 507 if (page) 5b8719504e3adf Jarkko Sakkinen 2021-03-18 508 break; 5b8719504e3adf Jarkko Sakkinen 2021-03-18 509 } 5b8719504e3adf Jarkko Sakkinen 2021-03-18 510 5b8719504e3adf Jarkko Sakkinen 2021-03-18 511 return page; d2285493bef310 Jarkko Sakkinen 2020-11-13 512 } d2285493bef310 Jarkko Sakkinen 2020-11-13 513 :::::: The code at line 496 was first introduced by commit :::::: d2285493bef310b66b56dfe4eb75c1e2f431ea5c x86/sgx: Add SGX page allocator functions :::::: TO: Jarkko Sakkinen <jarkko(a)kernel.org&gt; :::::: CC: Borislav Petkov <bp(a)suse.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org