BMC/Intel-BMC/linux.git/mm/z3fold.c, branch dev-5.2

mm/z3fold.c: fix race between migration and destruction

2019-08-29T06:30:25+00:00

commit d776aaa9895eb6eb770908e899cb7f5bd5025b3c upstream. In z3fold_destroy_pool() we call destroy_workqueue(&pool->compact_wq). However, we have no guarantee that migration isn't happening in the background at that time. Migration directly calls queue_work_on(pool->compact_wq), if destruction wins that race we are using a destroyed workqueue. Link: http://lkml.kernel.org/r/20190809213828.202833-1-henryburns@google.com Signed-off-by: Henry Burns Cc: Vitaly Wool Cc: Shakeel Butt Cc: Jonathan Adams Cc: Henry Burns Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/z3fold.c: fix z3fold_destroy_pool() race condition

2019-08-25T14:10:21+00:00

commit b997052bc3ac444a0bceab1093aff7ae71ed419e upstream. The constraint from the zpool use of z3fold_destroy_pool() is there are no outstanding handles to memory (so no active allocations), but it is possible for there to be outstanding work on either of the two wqs in the pool. Calling z3fold_deregister_migration() before the workqueues are drained means that there can be allocated pages referencing a freed inode, causing any thread in compaction to be able to trip over the bad pointer in PageMovable(). Link: http://lkml.kernel.org/r/20190726224810.79660-2-henryburns@google.com Fixes: 1f862989b04a ("mm/z3fold.c: support page migration") Signed-off-by: Henry Burns Reviewed-by: Shakeel Butt Reviewed-by: Jonathan Adams Cc: Vitaly Vul Cc: Vitaly Wool Cc: David Howells Cc: Thomas Gleixner Cc: Al Viro Cc: Henry Burns Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/z3fold.c: fix z3fold_destroy_pool() ordering

2019-08-25T14:10:21+00:00

commit 6051d3bd3b91e96c59e62b8be2dba1cc2b19ee40 upstream. The constraint from the zpool use of z3fold_destroy_pool() is there are no outstanding handles to memory (so no active allocations), but it is possible for there to be outstanding work on either of the two wqs in the pool. If there is work queued on pool->compact_workqueue when it is called, z3fold_destroy_pool() will do: z3fold_destroy_pool() destroy_workqueue(pool->release_wq) destroy_workqueue(pool->compact_wq) drain_workqueue(pool->compact_wq) do_compact_page(zhdr) kref_put(&zhdr->refcount) __release_z3fold_page(zhdr, ...) queue_work_on(pool->release_wq, &pool->work) *BOOM* So compact_wq needs to be destroyed before release_wq. Link: http://lkml.kernel.org/r/20190726224810.79660-1-henryburns@google.com Fixes: 5d03a6613957 ("mm/z3fold.c: use kref to prevent page free/compact race") Signed-off-by: Henry Burns Reviewed-by: Shakeel Butt Reviewed-by: Jonathan Adams Cc: Vitaly Vul Cc: Vitaly Wool Cc: David Howells Cc: Thomas Gleixner Cc: Al Viro Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/z3fold.c: reinitialize zhdr structs after migration

2019-08-06T17:08:10+00:00

[ Upstream commit c92d2f38563db20c20c8db2f98fa1349290477d5 ] z3fold_page_migration() calls memcpy(new_zhdr, zhdr, PAGE_SIZE). However, zhdr contains fields that can't be directly coppied over (ex: list_head, a circular linked list). We only need to initialize the linked lists in new_zhdr, as z3fold_isolate_page() already ensures that these lists are empty Additionally it is possible that zhdr->work has been placed in a workqueue. In this case we shouldn't migrate the page, as zhdr->work references zhdr as opposed to new_zhdr. Link: http://lkml.kernel.org/r/20190716000520.230595-1-henryburns@google.com Fixes: 1f862989b04ade61d3 ("mm/z3fold.c: support page migration") Signed-off-by: Henry Burns Reviewed-by: Shakeel Butt Cc: Vitaly Vul Cc: Vitaly Wool Cc: Jonathan Adams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/z3fold: don't try to use buddy slots after free

2019-08-06T17:08:10+00:00

[ Upstream commit bb9a374dfa3a2f46581455ab66cd1d24c5e3d183 ] As reported by Henry Burns: Running z3fold stress testing with address sanitization showed zhdr->slots was being used after it was freed. z3fold_free(z3fold_pool, handle) free_handle(handle) kmem_cache_free(pool->c_handle, zhdr->slots) release_z3fold_page_locked_list(kref) __release_z3fold_page(zhdr, true) zhdr_to_pool(zhdr) slots_to_pool(zhdr->slots) *BOOM* To fix this, add pointer to the pool back to z3fold_header and modify zhdr_to_pool to return zhdr->pool. Link: http://lkml.kernel.org/r/20190708134808.e89f3bfadd9f6ffd7eff9ba9@gmail.com Fixes: 7c2b8baa61fe ("mm/z3fold.c: add structure for buddy handles") Signed-off-by: Vitaly Wool Reported-by: Henry Burns Reviewed-by: Shakeel Butt Cc: Jonathan Adams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/z3fold.c: lock z3fold page before __SetPageMovable()

2019-07-26T07:11:07+00:00

commit 810481a246089117d98e3373a3cb735c3efc1f90 upstream. Following zsmalloc.c's example we call trylock_page() and unlock_page(). Also make z3fold_page_migrate() assert that newpage is passed in locked, as per the documentation. [akpm@linux-foundation.org: fix trylock_page return value test, per Shakeel] Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com Link: http://lkml.kernel.org/r/20190702233538.52793-1-henryburns@google.com Signed-off-by: Henry Burns Suggested-by: Vitaly Wool Acked-by: Vitaly Wool Acked-by: David Rientjes Reviewed-by: Shakeel Butt Cc: Vitaly Vul Cc: Mike Rapoport Cc: Xidong Wang Cc: Jonathan Adams Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

z3fold: fix sheduling while atomic

2019-06-01T22:51:31+00:00

kmem_cache_alloc() may be called from z3fold_alloc() in atomic context, so we need to pass correct gfp flags to avoid "scheduling while atomic" bug. Link: http://lkml.kernel.org/r/20190523153245.119dfeed55927e8755250ddd@gmail.com Fixes: 7c2b8baa61fe5 ("mm/z3fold.c: add structure for buddy handles") Signed-off-by: Vitaly Wool Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

treewide: Add SPDX license identifier for more missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

mm/z3fold.c: support page migration

2019-05-14T16:47:50+00:00

Now that we are not using page address in handles directly, we can make z3fold pages movable to decrease the memory fragmentation z3fold may create over time. This patch starts advertising non-headless z3fold pages as movable and uses the existing kernel infrastructure to implement moving of such pages per memory management subsystem's request. It thus implements 3 required callbacks for page migration: * isolation callback: z3fold_page_isolate(): try to isolate the page by removing it from all lists. Pages scheduled for some activity and mapped pages will not be isolated. Return true if isolation was successful or false otherwise * migration callback: z3fold_page_migrate(): re-check critical conditions and migrate page contents to the new page provided by the memory subsystem. Returns 0 on success or negative error code otherwise * putback callback: z3fold_page_putback(): put back the page if z3fold_page_migrate() for it failed permanently (i. e. not with -EAGAIN code). [lkp@intel.com: z3fold_page_isolate() can be static] Link: http://lkml.kernel.org/r/20190419130924.GA161478@ivb42 Link: http://lkml.kernel.org/r/20190417103922.31253da5c366c4ebe0419cfc@gmail.com Signed-off-by: Vitaly Wool Signed-off-by: kbuild test robot Cc: Bartlomiej Zolnierkiewicz Cc: Dan Streetman Cc: Krzysztof Kozlowski Cc: Oleksiy Avramchenko Cc: Uladzislau Rezki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/z3fold.c: add structure for buddy handles

2019-05-14T16:47:50+00:00

For z3fold to be able to move its pages per request of the memory subsystem, it should not use direct object addresses in handles. Instead, it will create abstract handles (3 per page) which will contain pointers to z3fold objects. Thus, it will be possible to change these pointers when z3fold page is moved. Link: http://lkml.kernel.org/r/20190417103826.484eaf18c1294d682769880f@gmail.com Signed-off-by: Vitaly Wool Cc: Bartlomiej Zolnierkiewicz Cc: Dan Streetman Cc: Krzysztof Kozlowski Cc: Oleksiy Avramchenko Cc: Uladzislau Rezki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds