tree: https://git.kernel.org/pub/scm/linux/kernel/git/rw/uml.git linux-next head: 1aee020155f364ef538370d3392969f1077b9bae commit: dd3035a21ba7ccaa883d7107d357ad06320d78fc [13/19] um: add a UML specific futex implementation config: um-x86_64_defconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.3-341-g8af24329-dirty # https://git.kernel.org/pub/scm/linux/kernel/git/rw/uml.git/commit/?id=dd3... git remote add uml https://git.kernel.org/pub/scm/linux/kernel/git/rw/uml.git git fetch --no-tags uml linux-next git checkout dd3035a21ba7ccaa883d7107d357ad06320d78fc # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=um SUBARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) arch/um/kernel/skas/uaccess.c:292:15: sparse: expected unsigned int [noderef] [usertype] __user *uaddr arch/um/kernel/skas/uaccess.c:292:15: sparse: got unsigned int [usertype] * arch/um/kernel/skas/uaccess.c:366:15: sparse: expected unsigned int [noderef] [usertype] __user *uaddr arch/um/kernel/skas/uaccess.c:366:15: sparse: got void * arch/um/kernel/skas/uaccess.c:373:15: sparse: expected void const volatile *v arch/um/kernel/skas/uaccess.c:373:15: sparse: got unsigned int [noderef] [usertype] __user *__ai_ptr arch/um/kernel/skas/uaccess.c:299:18: sparse: sparse: dereference of noderef expression arch/um/kernel/skas/uaccess.c:302:18: sparse: sparse: dereference of noderef expression arch/um/kernel/skas/uaccess.c:305:18: sparse: sparse: dereference of noderef expression arch/um/kernel/skas/uaccess.c:308:18: sparse: sparse: dereference of noderef expression arch/um/kernel/skas/uaccess.c:311:18: sparse: sparse: dereference of noderef expression arch/um/kernel/skas/uaccess.c:371:18: sparse: sparse: dereference of noderef expression vim +292 arch/um/kernel/skas/uaccess.c 252 253 /** 254 * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant 255 * argument and comparison of the previous 256 * futex value with another constant. 257 * 258 * @encoded_op: encoded operation to execute 259 * @uaddr: pointer to user space address 260 * 261 * Return: 262 * 0 - On success 263 * -EFAULT - User access resulted in a page fault 264 * -EAGAIN - Atomic operation was unable to complete due to contention 265 * -ENOSYS - Operation not supported 266 */ 267 268 int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr) 269 { 270 int oldval, ret; 271 struct page *page; 272 unsigned long addr = (unsigned long) uaddr; 273 pte_t *pte; 274 275 ret = -EFAULT; 276 if (!access_ok(uaddr, sizeof(*uaddr))) 277 return -EFAULT; 278 preempt_disable(); 279 pte = maybe_map(addr, 1); 280 if (pte == NULL) 281 goto out_inuser; 282 283 page = pte_page(*pte); 284 #ifdef CONFIG_64BIT 285 pagefault_disable(); 286 addr = (unsigned long) page_address(page) + 287 (((unsigned long) addr) & ~PAGE_MASK); 288 #else 289 addr = (unsigned long) kmap_atomic(page) + 290 ((unsigned long) addr & ~PAGE_MASK); 291 #endif 294 295 ret = 0; 296 297 switch (op) { 298 case FUTEX_OP_SET: 299 *uaddr = oparg; 300 break; 301 case FUTEX_OP_ADD: 302 *uaddr += oparg; 303 break; 304 case FUTEX_OP_OR: 305 *uaddr |= oparg; 306 break; 307 case FUTEX_OP_ANDN: 308 *uaddr &= ~oparg; 309 break; 310 case FUTEX_OP_XOR: 311 *uaddr ^= oparg; 312 break; 313 default: 314 ret = -ENOSYS; 315 } 316 #ifdef CONFIG_64BIT 317 pagefault_enable(); 318 #else 319 kunmap_atomic((void *)addr); 320 #endif 321 322 out_inuser: 323 preempt_enable(); 324 325 if (ret == 0) 326 *oval = oldval; 327 328 return ret; 329 } 330 EXPORT_SYMBOL(arch_futex_atomic_op_inuser); 331 332 /** 333 * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the 334 * uaddr with newval if the current value is 335 * oldval. 336 * @uval: pointer to store content of @uaddr 337 * @uaddr: pointer to user space address 338 * @oldval: old value 339 * @newval: new value to store to @uaddr 340 * 341 * Return: 342 * 0 - On success 343 * -EFAULT - User access resulted in a page fault 344 * -EAGAIN - Atomic operation was unable to complete due to contention 345 * -ENOSYS - Function not implemented (only if !HAVE_FUTEX_CMPXCHG) 346 */ 347 348 int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 349 u32 oldval, u32 newval) 350 { 351 struct page *page; 352 pte_t *pte; 353 int ret = -EFAULT; 354 355 if (!access_ok(uaddr, sizeof(*uaddr))) 356 return -EFAULT; 357 358 preempt_disable(); 359 pte = maybe_map((unsigned long) uaddr, 1); 360 if (pte == NULL) 361 goto out_inatomic; 362 363 page = pte_page(*pte); 364 #ifdef CONFIG_64BIT 365 pagefault_disable(); 367 #else 368 uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK); 369 #endif 370 371 *uval = *uaddr; 372 374 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org