Got this after sending v2 but it will have the same problem. This occurs for CONFIG_MMU=n which seems to be broken anyway due to other arch build errors (at least for Arm SA1100 based builds). Fixing this is easy enough though - only defining migration_entry_wait_on_locked() when CONFIG_MIGRATION=y fixes this and is probably a good idea anyway. I will wait a bit for feedback on v2 before sending v3 with this fix. - Alistair On Friday, 5 November 2021 8:50:08 PM AEDT kernel test robot wrote: > Hi Alistair, > > Thank you for the patch! Yet something to improve: > > [auto build test ERROR on linux/master] > [also build test ERROR on v5.15] > [cannot apply to hnaz-mm/master linus/master next-20211105] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use '--base' as documented in > https://git-scm.com/docs/git-format-patch] > > url: https://github.com/0day-ci/linux/commits/Alistair-Popple/mm-migrate-c-Rework-migration_entry_wait-to-not-take-a-pageref/20211104-183442 > base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2f111a6fd5b5297b4e92f53798ca086f7c7d33a4 > config: arm-randconfig-r026-20211105 (attached as .config) > compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 847a6807332b13f43704327c2d30103ec0347c77) > 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 arm cross compiling tool for clang build > # apt-get install binutils-arm-linux-gnueabi > # https://github.com/0day-ci/linux/commit/e9447498f8f8758741f3dae044c3e4593130595c > git remote add linux-review https://github.com/0day-ci/linux > git fetch --no-tags linux-review Alistair-Popple/mm-migrate-c-Rework-migration_entry_wait-to-not-take-a-pageref/20211104-183442 > git checkout e9447498f8f8758741f3dae044c3e4593130595c > # save the attached .config to linux build tree > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All errors (new ones prefixed by >>): > > >> mm/filemap.c:1468:2: error: implicit declaration of function 'pte_unmap' [-Werror,-Wimplicit-function-declaration] > pte_unmap_unlock(ptep, ptl); > ^ > include/linux/mm.h:2275:2: note: expanded from macro 'pte_unmap_unlock' > pte_unmap(pte); \ > ^ > 1 error generated. > > > vim +/pte_unmap +1468 mm/filemap.c > > 1413 > 1414 /** > 1415 * migration_entry_wait_on_locked - Wait for a migration entry to be removed > 1416 * @page: page referenced by the migration entry. > 1417 * @ptep: mapped pte pointer. This function will return with the ptep unmapped. > 1418 * @ptl: already locked ptl. This function will drop the lock. > 1419 * > 1420 * Wait for a migration entry referencing the given page to be removed. This is > 1421 * equivalent to put_and_wait_on_page_locked(page, TASK_UNINTERRUPTIBLE) except > 1422 * this can be called without taking a reference on the page. Instead this > 1423 * should be called while holding the ptl for the migration entry referencing > 1424 * the page. > 1425 * > 1426 * Returns after unmapping and unlocking the pte/ptl with pte_unmap_unlock(). > 1427 * > 1428 * This follows the same logic as wait_on_page_bit_common() so see the comments > 1429 * there. > 1430 */ > 1431 void migration_entry_wait_on_locked(struct page *page, pte_t *ptep, > 1432 spinlock_t *ptl) > 1433 { > 1434 struct wait_page_queue wait_page; > 1435 wait_queue_entry_t *wait = &wait_page.wait; > 1436 bool thrashing = false; > 1437 bool delayacct = false; > 1438 unsigned long pflags; > 1439 wait_queue_head_t *q; > 1440 > 1441 q = page_waitqueue(page); > 1442 if (!PageUptodate(page) && PageWorkingset(page)) { > 1443 if (!PageSwapBacked(page)) { > 1444 delayacct_thrashing_start(); > 1445 delayacct = true; > 1446 } > 1447 psi_memstall_enter(&pflags); > 1448 thrashing = true; > 1449 } > 1450 > 1451 init_wait(wait); > 1452 wait->func = wake_page_function; > 1453 wait_page.page = page; > 1454 wait_page.bit_nr = PG_locked; > 1455 wait->flags = 0; > 1456 > 1457 spin_lock_irq(&q->lock); > 1458 SetPageWaiters(page); > 1459 if (!trylock_page_bit_common(page, PG_locked, wait)) > 1460 __add_wait_queue_entry_tail(q, wait); > 1461 spin_unlock_irq(&q->lock); > 1462 > 1463 /* > 1464 * If a migration entry exists for the page the migration path must hold > 1465 * a valid reference to the page, and it must take the ptl to remove the > 1466 * migration entry. So the page is valid until the ptl is dropped. > 1467 */ > > 1468 pte_unmap_unlock(ptep, ptl); > 1469 > 1470 for (;;) { > 1471 unsigned int flags; > 1472 > 1473 set_current_state(TASK_UNINTERRUPTIBLE); > 1474 > 1475 /* Loop until we've been woken or interrupted */ > 1476 flags = smp_load_acquire(&wait->flags); > 1477 if (!(flags & WQ_FLAG_WOKEN)) { > 1478 if (signal_pending_state(TASK_UNINTERRUPTIBLE, current)) > 1479 break; > 1480 > 1481 io_schedule(); > 1482 continue; > 1483 } > 1484 break; > 1485 } > 1486 > 1487 finish_wait(q, wait); > 1488 > 1489 if (thrashing) { > 1490 if (delayacct) > 1491 delayacct_thrashing_end(); > 1492 psi_memstall_leave(&pflags); > 1493 } > 1494 } > 1495 > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx >
