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2019-08-13mm/vmalloc.c: fix percpu free VM area search criteriaKuppuswamy Sathyanarayanan
Recent changes to the vmalloc code by commit 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation") can cause spurious percpu allocation failures. These, in turn, can result in panic()s in the slub code. One such possible panic was reported by Dave Hansen in following link https://lkml.org/lkml/2019/6/19/939. Another related panic observed is, RIP: 0033:0x7f46f7441b9b Call Trace: dump_stack+0x61/0x80 pcpu_alloc.cold.30+0x22/0x4f mem_cgroup_css_alloc+0x110/0x650 cgroup_apply_control_enable+0x133/0x330 cgroup_mkdir+0x41b/0x500 kernfs_iop_mkdir+0x5a/0x90 vfs_mkdir+0x102/0x1b0 do_mkdirat+0x7d/0xf0 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 VMALLOC memory manager divides the entire VMALLOC space (VMALLOC_START to VMALLOC_END) into multiple VM areas (struct vm_areas), and it mainly uses two lists (vmap_area_list & free_vmap_area_list) to track the used and free VM areas in VMALLOC space. And pcpu_get_vm_areas(offsets[], sizes[], nr_vms, align) function is used for allocating congruent VM areas for percpu memory allocator. In order to not conflict with VMALLOC users, pcpu_get_vm_areas allocates VM areas near the end of the VMALLOC space. So the search for free vm_area for the given requirement starts near VMALLOC_END and moves upwards towards VMALLOC_START. Prior to commit 68ad4a330433, the search for free vm_area in pcpu_get_vm_areas() involves following two main steps. Step 1: Find a aligned "base" adress near VMALLOC_END. va = free vm area near VMALLOC_END Step 2: Loop through number of requested vm_areas and check, Step 2.1: if (base < VMALLOC_START) 1. fail with error Step 2.2: // end is offsets[area] + sizes[area] if (base + end > va->vm_end) 1. Move the base downwards and repeat Step 2 Step 2.3: if (base + start < va->vm_start) 1. Move to previous free vm_area node, find aligned base address and repeat Step 2 But Commit 68ad4a330433 removed Step 2.2 and modified Step 2.3 as below: Step 2.3: if (base + start < va->vm_start || base + end > va->vm_end) 1. Move to previous free vm_area node, find aligned base address and repeat Step 2 Above change is the root cause of spurious percpu memory allocation failures. For example, consider a case where a relatively large vm_area (~ 30 TB) was ignored in free vm_area search because it did not pass the base + end < vm->vm_end boundary check. Ignoring such large free vm_area's would lead to not finding free vm_area within boundary of VMALLOC_start to VMALLOC_END which in turn leads to allocation failures. So modify the search algorithm to include Step 2.2. Link: http://lkml.kernel.org/r/20190729232139.91131-1-sathyanarayanan.kuppuswamy@linux.intel.com Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation") Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Reported-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: sathyanarayanan kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm/memcontrol.c: fix use after free in mem_cgroup_iter()Miles Chen
This patch is sent to report an use after free in mem_cgroup_iter() after merging commit be2657752e9e ("mm: memcg: fix use after free in mem_cgroup_iter()"). I work with android kernel tree (4.9 & 4.14), and commit be2657752e9e ("mm: memcg: fix use after free in mem_cgroup_iter()") has been merged to the trees. However, I can still observe use after free issues addressed in the commit be2657752e9e. (on low-end devices, a few times this month) backtrace: css_tryget <- crash here mem_cgroup_iter shrink_node shrink_zones do_try_to_free_pages try_to_free_pages __perform_reclaim __alloc_pages_direct_reclaim __alloc_pages_slowpath __alloc_pages_nodemask To debug, I poisoned mem_cgroup before freeing it: static void __mem_cgroup_free(struct mem_cgroup *memcg) for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); free_percpu(memcg->stat); + /* poison memcg before freeing it */ + memset(memcg, 0x78, sizeof(struct mem_cgroup)); kfree(memcg); } The coredump shows the position=0xdbbc2a00 is freed. (gdb) p/x ((struct mem_cgroup_per_node *)0xe5009e00)->iter[8] $13 = {position = 0xdbbc2a00, generation = 0x2efd} 0xdbbc2a00: 0xdbbc2e00 0x00000000 0xdbbc2800 0x00000100 0xdbbc2a10: 0x00000200 0x78787878 0x00026218 0x00000000 0xdbbc2a20: 0xdcad6000 0x00000001 0x78787800 0x00000000 0xdbbc2a30: 0x78780000 0x00000000 0x0068fb84 0x78787878 0xdbbc2a40: 0x78787878 0x78787878 0x78787878 0xe3fa5cc0 0xdbbc2a50: 0x78787878 0x78787878 0x00000000 0x00000000 0xdbbc2a60: 0x00000000 0x00000000 0x00000000 0x00000000 0xdbbc2a70: 0x00000000 0x00000000 0x00000000 0x00000000 0xdbbc2a80: 0x00000000 0x00000000 0x00000000 0x00000000 0xdbbc2a90: 0x00000001 0x00000000 0x00000000 0x00100000 0xdbbc2aa0: 0x00000001 0xdbbc2ac8 0x00000000 0x00000000 0xdbbc2ab0: 0x00000000 0x00000000 0x00000000 0x00000000 0xdbbc2ac0: 0x00000000 0x00000000 0xe5b02618 0x00001000 0xdbbc2ad0: 0x00000000 0x78787878 0x78787878 0x78787878 0xdbbc2ae0: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2af0: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b00: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b10: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b20: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b30: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b40: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b50: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b60: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b70: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2b80: 0x78787878 0x78787878 0x00000000 0x78787878 0xdbbc2b90: 0x78787878 0x78787878 0x78787878 0x78787878 0xdbbc2ba0: 0x78787878 0x78787878 0x78787878 0x78787878 In the reclaim path, try_to_free_pages() does not setup sc.target_mem_cgroup and sc is passed to do_try_to_free_pages(), ..., shrink_node(). In mem_cgroup_iter(), root is set to root_mem_cgroup because sc->target_mem_cgroup is NULL. It is possible to assign a memcg to root_mem_cgroup.nodeinfo.iter in mem_cgroup_iter(). try_to_free_pages struct scan_control sc = {...}, target_mem_cgroup is 0x0; do_try_to_free_pages shrink_zones shrink_node mem_cgroup *root = sc->target_mem_cgroup; memcg = mem_cgroup_iter(root, NULL, &reclaim); mem_cgroup_iter() if (!root) root = root_mem_cgroup; ... css = css_next_descendant_pre(css, &root->css); memcg = mem_cgroup_from_css(css); cmpxchg(&iter->position, pos, memcg); My device uses memcg non-hierarchical mode. When we release a memcg: invalidate_reclaim_iterators() reaches only dead_memcg and its parents. If non-hierarchical mode is used, invalidate_reclaim_iterators() never reaches root_mem_cgroup. static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) { struct mem_cgroup *memcg = dead_memcg; for (; memcg; memcg = parent_mem_cgroup(memcg) ... } So the use after free scenario looks like: CPU1 CPU2 try_to_free_pages do_try_to_free_pages shrink_zones shrink_node mem_cgroup_iter() if (!root) root = root_mem_cgroup; ... css = css_next_descendant_pre(css, &root->css); memcg = mem_cgroup_from_css(css); cmpxchg(&iter->position, pos, memcg); invalidate_reclaim_iterators(memcg); ... __mem_cgroup_free() kfree(memcg); try_to_free_pages do_try_to_free_pages shrink_zones shrink_node mem_cgroup_iter() if (!root) root = root_mem_cgroup; ... mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id); iter = &mz->iter[reclaim->priority]; pos = READ_ONCE(iter->position); css_tryget(&pos->css) <- use after free To avoid this, we should also invalidate root_mem_cgroup.nodeinfo.iter in invalidate_reclaim_iterators(). [cai@lca.pw: fix -Wparentheses compilation warning] Link: http://lkml.kernel.org/r/1564580753-17531-1-git-send-email-cai@lca.pw Link: http://lkml.kernel.org/r/20190730015729.4406-1-miles.chen@mediatek.com Fixes: 5ac8fb31ad2e ("mm: memcontrol: convert reclaim iterator to simple css refcounting") Signed-off-by: Miles Chen <miles.chen@mediatek.com> Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm/z3fold.c: fix z3fold_destroy_pool() race conditionHenry Burns
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 <henryburns@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Jonathan Adams <jwadams@google.com> Cc: Vitaly Vul <vitaly.vul@sony.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Henry Burns <henrywolfeburns@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm/z3fold.c: fix z3fold_destroy_pool() orderingHenry Burns
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 <henryburns@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Jonathan Adams <jwadams@google.com> Cc: Vitaly Vul <vitaly.vul@sony.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk Cc: Henry Burns <henrywolfeburns@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm: mempolicy: handle vma with unmovable pages mapped correctly in mbindYang Shi
When running syzkaller internally, we ran into the below bug on 4.9.x kernel: kernel BUG at mm/huge_memory.c:2124! invalid opcode: 0000 [#1] SMP KASAN CPU: 0 PID: 1518 Comm: syz-executor107 Not tainted 4.9.168+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011 task: ffff880067b34900 task.stack: ffff880068998000 RIP: split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124 Call Trace: split_huge_page include/linux/huge_mm.h:100 [inline] queue_pages_pte_range+0x7e1/0x1480 mm/mempolicy.c:538 walk_pmd_range mm/pagewalk.c:50 [inline] walk_pud_range mm/pagewalk.c:90 [inline] walk_pgd_range mm/pagewalk.c:116 [inline] __walk_page_range+0x44a/0xdb0 mm/pagewalk.c:208 walk_page_range+0x154/0x370 mm/pagewalk.c:285 queue_pages_range+0x115/0x150 mm/mempolicy.c:694 do_mbind mm/mempolicy.c:1241 [inline] SYSC_mbind+0x3c3/0x1030 mm/mempolicy.c:1370 SyS_mbind+0x46/0x60 mm/mempolicy.c:1352 do_syscall_64+0x1d2/0x600 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: c7 80 1c 02 00 e8 26 0a 76 01 <0f> 0b 48 c7 c7 40 46 45 84 e8 4c RIP [<ffffffff81895d6b>] split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124 RSP <ffff88006899f980> with the below test: uint64_t r[1] = {0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); intptr_t res = 0; res = syscall(__NR_socket, 0x11, 3, 0x300); if (res != -1) r[0] = res; *(uint32_t*)0x20000040 = 0x10000; *(uint32_t*)0x20000044 = 1; *(uint32_t*)0x20000048 = 0xc520; *(uint32_t*)0x2000004c = 1; syscall(__NR_setsockopt, r[0], 0x107, 0xd, 0x20000040, 0x10); syscall(__NR_mmap, 0x20fed000, 0x10000, 0, 0x8811, r[0], 0); *(uint64_t*)0x20000340 = 2; syscall(__NR_mbind, 0x20ff9000, 0x4000, 0x4002, 0x20000340, 0x45d4, 3); return 0; } Actually the test does: mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 socket(AF_PACKET, SOCK_RAW, 768) = 3 setsockopt(3, SOL_PACKET, PACKET_TX_RING, {block_size=65536, block_nr=1, frame_size=50464, frame_nr=1}, 16) = 0 mmap(0x20fed000, 65536, PROT_NONE, MAP_SHARED|MAP_FIXED|MAP_POPULATE|MAP_DENYWRITE, 3, 0) = 0x20fed000 mbind(..., MPOL_MF_STRICT|MPOL_MF_MOVE) = 0 The setsockopt() would allocate compound pages (16 pages in this test) for packet tx ring, then the mmap() would call packet_mmap() to map the pages into the user address space specified by the mmap() call. When calling mbind(), it would scan the vma to queue the pages for migration to the new node. It would split any huge page since 4.9 doesn't support THP migration, however, the packet tx ring compound pages are not THP and even not movable. So, the above bug is triggered. However, the later kernel is not hit by this issue due to commit d44d363f6578 ("mm: don't assume anonymous pages have SwapBacked flag"), which just removes the PageSwapBacked check for a different reason. But, there is a deeper issue. According to the semantic of mbind(), it should return -EIO if MPOL_MF_MOVE or MPOL_MF_MOVE_ALL was specified and MPOL_MF_STRICT was also specified, but the kernel was unable to move all existing pages in the range. The tx ring of the packet socket is definitely not movable, however, mbind() returns success for this case. Although the most socket file associates with non-movable pages, but XDP may have movable pages from gup. So, it sounds not fine to just check the underlying file type of vma in vma_migratable(). Change migrate_page_add() to check if the page is movable or not, if it is unmovable, just return -EIO. But do not abort pte walk immediately, since there may be pages off LRU temporarily. We should migrate other pages if MPOL_MF_MOVE* is specified. Set has_unmovable flag if some paged could not be not moved, then return -EIO for mbind() eventually. With this change the above test would return -EIO as expected. [yang.shi@linux.alibaba.com: fix review comments from Vlastimil] Link: http://lkml.kernel.org/r/1563556862-54056-3-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1561162809-59140-3-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and ↵Yang Shi
MPOL_MF_STRICT were specified When both MPOL_MF_MOVE* and MPOL_MF_STRICT was specified, mbind() should try best to migrate misplaced pages, if some of the pages could not be migrated, then return -EIO. There are three different sub-cases: 1. vma is not migratable 2. vma is migratable, but there are unmovable pages 3. vma is migratable, pages are movable, but migrate_pages() fails If #1 happens, kernel would just abort immediately, then return -EIO, after a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified"). If #3 happens, kernel would set policy and migrate pages with best-effort, but won't rollback the migrated pages and reset the policy back. Before that commit, they behaves in the same way. It'd better to keep their behavior consistent. But, rolling back the migrated pages and resetting the policy back sounds not feasible, so just make #1 behave as same as #3. Userspace will know that not everything was successfully migrated (via -EIO), and can take whatever steps it deems necessary - attempt rollback, determine which exact page(s) are violating the policy, etc. Make queue_pages_range() return 1 to indicate there are unmovable pages or vma is not migratable. The #2 is not handled correctly in the current kernel, the following patch will fix it. [yang.shi@linux.alibaba.com: fix review comments from Vlastimil] Link: http://lkml.kernel.org/r/1563556862-54056-2-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1561162809-59140-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm/hmm: fix bad subpage pointer in try_to_unmap_oneRalph Campbell
When migrating an anonymous private page to a ZONE_DEVICE private page, the source page->mapping and page->index fields are copied to the destination ZONE_DEVICE struct page and the page_mapcount() is increased. This is so rmap_walk() can be used to unmap and migrate the page back to system memory. However, try_to_unmap_one() computes the subpage pointer from a swap pte which computes an invalid page pointer and a kernel panic results such as: BUG: unable to handle page fault for address: ffffea1fffffffc8 Currently, only single pages can be migrated to device private memory so no subpage computation is needed and it can be set to "page". [rcampbell@nvidia.com: add comment] Link: http://lkml.kernel.org/r/20190724232700.23327-4-rcampbell@nvidia.com Link: http://lkml.kernel.org/r/20190719192955.30462-4-rcampbell@nvidia.com Fixes: a5430dda8a3a1c ("mm/migrate: support un-addressable ZONE_DEVICE page in migration") Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-13mm/hmm: fix ZONE_DEVICE anon page mapping reuseRalph Campbell
When a ZONE_DEVICE private page is freed, the page->mapping field can be set. If this page is reused as an anonymous page, the previous value can prevent the page from being inserted into the CPU's anon rmap table. For example, when migrating a pte_none() page to device memory: migrate_vma(ops, vma, start, end, src, dst, private) migrate_vma_collect() src[] = MIGRATE_PFN_MIGRATE migrate_vma_prepare() /* no page to lock or isolate so OK */ migrate_vma_unmap() /* no page to unmap so OK */ ops->alloc_and_copy() /* driver allocates ZONE_DEVICE page for dst[] */ migrate_vma_pages() migrate_vma_insert_page() page_add_new_anon_rmap() __page_set_anon_rmap() /* This check sees the page's stale mapping field */ if (PageAnon(page)) return /* page->mapping is not updated */ The result is that the migration appears to succeed but a subsequent CPU fault will be unable to migrate the page back to system memory or worse. Clear the page->mapping field when freeing the ZONE_DEVICE page so stale pointer data doesn't affect future page use. Link: http://lkml.kernel.org/r/20190719192955.30462-3-rcampbell@nvidia.com Fixes: b7a523109fb5c9d2d6dd ("mm: don't clear ->mapping in hmm_devmem_free") Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Kara <jack@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-09mm/memremap: Fix reuse of pgmap instances with internal referencesDan Williams
Currently, attempts to shutdown and re-enable a device-dax instance trigger: Missing reference count teardown definition WARNING: CPU: 37 PID: 1608 at mm/memremap.c:211 devm_memremap_pages+0x234/0x850 [..] RIP: 0010:devm_memremap_pages+0x234/0x850 [..] Call Trace: dev_dax_probe+0x66/0x190 [device_dax] really_probe+0xef/0x390 driver_probe_device+0xb4/0x100 device_driver_attach+0x4f/0x60 Given that the setup path initializes pgmap->ref, arrange for it to be also torn down so devm_memremap_pages() is ready to be called again and not be mistaken for the 3rd-party per-cpu-ref case. Fixes: 24917f6b1041 ("memremap: provide an optional internal refcount in struct dev_pagemap") Reported-by: Fan Du <fan.du@intel.com> Tested-by: Vishal Verma <vishal.l.verma@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/156530042781.2068700.8733813683117819799.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-08-07mm/hmm: make HMM_MIRROR an implicit optionChristoph Hellwig
Make HMM_MIRROR an option that is selected by drivers wanting to use it instead of a user visible option as it is just a low-level implementation detail. Link: https://lore.kernel.org/r/20190806160554.14046-15-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: allow HMM_MIRROR on all architectures with MMUChristoph Hellwig
There isn't really any architecture specific code in this page table walk implementation, so drop the dependencies. Link: https://lore.kernel.org/r/20190806160554.14046-14-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: cleanup the hmm_vma_walk_hugetlb_entry stubChristoph Hellwig
Stub out the whole function and assign NULL to the .hugetlb_entry method if CONFIG_HUGETLB_PAGE is not set, as the method won't ever be called in that case. Link: https://lore.kernel.org/r/20190806160554.14046-13-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: cleanup the hmm_vma_handle_pmd stubChristoph Hellwig
Stub out the whole function when CONFIG_TRANSPARENT_HUGEPAGE is not set to make the function easier to read. Link: https://lore.kernel.org/r/20190806160554.14046-12-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: only define hmm_vma_walk_pud if neededChristoph Hellwig
We only need the special pud_entry walker if PUD-sized hugepages and pte mappings are supported, else the common pagewalk code will take care of the iteration. Not implementing this callback reduced the amount of code compiled for non-x86 platforms, and also fixes compile failures with other architectures when helpers like pud_pfn are not implemented. Link: https://lore.kernel.org/r/20190806160554.14046-11-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: don't abuse pte_index() in hmm_vma_handle_pmdChristoph Hellwig
pte_index is an internal arch helper in various architectures, without consistent semantics. Open code that calculation of a PMD index based on the virtual address instead. Link: https://lore.kernel.org/r/20190806160554.14046-10-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: remove the mask variable in hmm_vma_walk_hugetlb_entryChristoph Hellwig
The pagewalk code already passes the value as the hmask parameter. Link: https://lore.kernel.org/r/20190806160554.14046-9-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: remove the page_shift member from struct hmm_rangeChristoph Hellwig
All users pass PAGE_SIZE here, and if we wanted to support single entries for huge pages we should really just add a HMM_FAULT_HUGEPAGE flag instead that uses the huge page size instead of having the caller calculate that size once, just for the hmm code to verify it. Link: https://lore.kernel.org/r/20190806160554.14046-8-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: remove superfluous arguments from hmm_range_registerChristoph Hellwig
The start, end and page_shift values are all saved in the range structure, so we might as well use that for argument passing. Link: https://lore.kernel.org/r/20190806160554.14046-7-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: remove the unused vma argument to hmm_range_dma_unmapChristoph Hellwig
Link: https://lore.kernel.org/r/20190806160554.14046-6-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-03memremap: move from kernel/ to mm/Christoph Hellwig
memremap.c implements MM functionality for ZONE_DEVICE, so it really should be in the mm/ directory, not the kernel/ one. Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm/memory_hotplug.c: remove unneeded return for void functionWeitao Hou
return is unneeded in void function Link: http://lkml.kernel.org/r/20190723130814.21826-1-houweitaoo@gmail.com Signed-off-by: Weitao Hou <houweitaoo@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm/migrate.c: initialize pud_entry in migrate_vma()Ralph Campbell
When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls migrate_vma_collect() which initializes a struct mm_walk but didn't initialize mm_walk.pud_entry. (Found by code inspection) Use a C structure initialization to make sure it is set to NULL. Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@nvidia.com Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with device memory") Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm: compaction: avoid 100% CPU usage during compaction when a task is killedMel Gorman
"howaboutsynergy" reported via kernel buzilla number 204165 that compact_zone_order was consuming 100% CPU during a stress test for prolonged periods of time. Specifically the following command, which should exit in 10 seconds, was taking an excessive time to finish while the CPU was pegged at 100%. stress -m 220 --vm-bytes 1000000000 --timeout 10 Tracing indicated a pattern as follows stress-3923 [007] 519.106208: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106212: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106216: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106219: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106223: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106227: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106231: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106235: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106238: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106242: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 Note that compaction is entered in rapid succession while scanning and isolating nothing. The problem is that when a task that is compacting receives a fatal signal, it retries indefinitely instead of exiting while making no progress as a fatal signal is pending. It's not easy to trigger this condition although enabling zswap helps on the basis that the timing is altered. A very small window has to be hit for the problem to occur (signal delivered while compacting and isolating a PFN for migration that is not aligned to SWAP_CLUSTER_MAX). This was reproduced locally -- 16G single socket system, 8G swap, 30% zswap configured, vm-bytes 22000000000 using Colin Kings stress-ng implementation from github running in a loop until the problem hits). Tracing recorded the problem occurring almost 200K times in a short window. With this patch, the problem hit 4 times but the task existed normally instead of consuming CPU. This problem has existed for some time but it was made worse by commit cf66f0700c8f ("mm, compaction: do not consider a need to reschedule as contention"). Before that commit, if the same condition was hit then locks would be quickly contended and compaction would exit that way. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204165 Link: http://lkml.kernel.org/r/20190718085708.GE24383@techsingularity.net Fixes: cf66f0700c8f ("mm, compaction: do not consider a need to reschedule as contention") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [5.1+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm: migrate: fix reference check race between __find_get_block() and migrationJan Kara
buffer_migrate_page_norefs() can race with bh users in the following way: CPU1 CPU2 buffer_migrate_page_norefs() buffer_migrate_lock_buffers() checks bh refs spin_unlock(&mapping->private_lock) __find_get_block() spin_lock(&mapping->private_lock) grab bh ref spin_unlock(&mapping->private_lock) move page do bh work This can result in various issues like lost updates to buffers (i.e. metadata corruption) or use after free issues for the old page. This patch closes the race by holding mapping->private_lock while the mapping is being moved to a new page. Ordinarily, a reference can be taken outside of the private_lock using the per-cpu BH LRU but the references are checked and the LRU invalidated if necessary. The private_lock is held once the references are known so the buffer lookup slow path will spin on the private_lock. Between the page lock and private_lock, it should be impossible for other references to be acquired and updates to happen during the migration. A user had reported data corruption issues on a distribution kernel with a similar page migration implementation as mainline. The data corruption could not be reproduced with this patch applied. A small number of migration-intensive tests were run and no performance problems were noted. [mgorman@techsingularity.net: Changelog, removed tracing] Link: http://lkml.kernel.org/r/20190718090238.GF24383@techsingularity.net Fixes: 89cb0888ca14 "mm: migrate: provide buffer_migrate_page_norefs()" Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [5.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab ↵Yang Shi
shrinker Shakeel Butt reported premature oom on kernel with "cgroup_disable=memory" since mem_cgroup_is_root() returns false even though memcg is actually NULL. The drop_caches is also broken. It is because commit aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") removed the !memcg check before !mem_cgroup_is_root(). And, surprisingly root memcg is allocated even though memory cgroup is disabled by kernel boot parameter. Add mem_cgroup_disabled() check to make reclaimer work as expected. Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com Fixes: aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reported-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jan Hadrava <had@kam.mff.cuni.cz> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Hugh Dickins <hughd@google.com> Cc: Qian Cai <cai@lca.pw> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> [4.19+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03Revert "kmemleak: allow to coexist with fault injection"Yang Shi
When running ltp's oom test with kmemleak enabled, the below warning was triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is passed in: WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50 Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50 ... kmemleak_alloc+0x4e/0xb0 kmem_cache_alloc+0x2a7/0x3e0 mempool_alloc_slab+0x2d/0x40 mempool_alloc+0x118/0x2b0 bio_alloc_bioset+0x19d/0x350 get_swap_bio+0x80/0x230 __swap_writepage+0x5ff/0xb20 The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak has __GFP_NOFAIL set all the time due to d9570ee3bd1d4f2 ("kmemleak: allow to coexist with fault injection"). But, it doesn't make any sense to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same time. According to the discussion on the mailing list, the commit should be reverted for short term solution. Catalin Marinas would follow up with a better solution for longer term. The failure rate of kmemleak metadata allocation may increase in some circumstances, but this should be expected side effect. Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com Fixes: d9570ee3bd1d4f2 ("kmemleak: allow to coexist with fault injection") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-31mm: slub: Fix slab walking for init_on_freeLaura Abbott
To properly clear the slab on free with slab_want_init_on_free, we walk the list of free objects using get_freepointer/set_freepointer. The value we get from get_freepointer may not be valid. This isn't an issue since an actual value will get written later but this means there's a chance of triggering a bug if we use this value with set_freepointer: kernel BUG at mm/slub.c:306! invalid opcode: 0000 [#1] PREEMPT PTI CPU: 0 PID: 0 Comm: swapper Not tainted 5.2.0-05754-g6471384a #4 RIP: 0010:kfree+0x58a/0x5c0 Code: 48 83 05 78 37 51 02 01 0f 0b 48 83 05 7e 37 51 02 01 48 83 05 7e 37 51 02 01 48 83 05 7e 37 51 02 01 48 83 05 d6 37 51 02 01 <0f> 0b 48 83 05 d4 37 51 02 01 48 83 05 d4 37 51 02 01 48 83 05 d4 RSP: 0000:ffffffff82603d90 EFLAGS: 00010002 RAX: ffff8c3976c04320 RBX: ffff8c3976c04300 RCX: 0000000000000000 RDX: ffff8c3976c04300 RSI: 0000000000000000 RDI: ffff8c3976c04320 RBP: ffffffff82603db8 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8c3976c04320 R11: ffffffff8289e1e0 R12: ffffd52cc8db0100 R13: ffff8c3976c01a00 R14: ffffffff810f10d4 R15: ffff8c3976c04300 FS: 0000000000000000(0000) GS:ffffffff8266b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8c397ffff000 CR3: 0000000125020000 CR4: 00000000000406b0 Call Trace: apply_wqattrs_prepare+0x154/0x280 apply_workqueue_attrs_locked+0x4e/0xe0 apply_workqueue_attrs+0x36/0x60 alloc_workqueue+0x25a/0x6d0 workqueue_init_early+0x246/0x348 start_kernel+0x3c7/0x7ec x86_64_start_reservations+0x40/0x49 x86_64_start_kernel+0xda/0xe4 secondary_startup_64+0xb6/0xc0 Modules linked in: ---[ end trace f67eb9af4d8d492b ]--- Fix this by ensuring the value we set with set_freepointer is either NULL or another value in the chain. Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options") Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-30Merge tag 'for-linus-hmm' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma Pull HMM fixes from Jason Gunthorpe: "Fix the locking around nouveau's use of the hmm_range_* APIs. It works correctly in the success case, but many of the the edge cases have missing unlocks or double unlocks. The diffstat is a bit big as Christoph did a comprehensive job to move the obsolete API from the core header and into the driver before fixing its flow, but the risk of regression from this code motion is low" * tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: nouveau: unlock mmap_sem on all errors from nouveau_range_fault nouveau: remove the block parameter to nouveau_range_fault mm/hmm: move hmm_vma_range_done and hmm_vma_fault to nouveau mm/hmm: always return EBUSY for invalid ranges in hmm_range_{fault,snapshot}
2019-07-29Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds
Pull virtio/vhost fixes from Michael Tsirkin: - Fixes in the iommu and balloon devices. - Disable the meta-data optimization for now - I hope we can get it fixed shortly, but there's no point in making users suffer crashes while we are working on that. * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost: disable metadata prefetch optimization iommu/virtio: Update to most recent specification balloon: fix up comments mm/balloon_compaction: avoid duplicate page removal
2019-07-26mm/hmm: remove hmm_range vmaRalph Campbell
Since hmm_range_fault() doesn't use the struct hmm_range vma field, remove it. Link: https://lore.kernel.org/r/20190726005650.2566-8-rcampbell@nvidia.com Suggested-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: remove hugetlbfs check in hmm_vma_walk_pmdRalph Campbell
walk_page_range() will only call hmm_vma_walk_hugetlb_entry() for hugetlbfs pages and doesn't call hmm_vma_walk_pmd() in this case. Therefore, it is safe to remove the check for vma->vm_flags & VM_HUGETLB in hmm_vma_walk_pmd(). Link: https://lore.kernel.org/r/20190726005650.2566-7-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: merge hmm_range_snapshot into hmm_range_faultChristoph Hellwig
Add a HMM_FAULT_SNAPSHOT flag so that hmm_range_snapshot can be merged into the almost identical hmm_range_fault function. Link: https://lore.kernel.org/r/20190726005650.2566-5-rcampbell@nvidia.com Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: replace the block argument to hmm_range_fault with a flags valueChristoph Hellwig
This allows easier expansion to other flags, and also makes the callers a little easier to read. Link: https://lore.kernel.org/r/20190726005650.2566-4-rcampbell@nvidia.com Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: a few more C style and comment clean upsRalph Campbell
A few more comments and minor programming style clean ups. There should be no functional changes. Link: https://lore.kernel.org/r/20190726005650.2566-3-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: replace hmm_update with mmu_notifier_rangeRalph Campbell
The hmm_mirror_ops callback function sync_cpu_device_pagetables() passes a struct hmm_update which is a simplified version of struct mmu_notifier_range. This is unnecessary so replace hmm_update with mmu_notifier_range directly. Link: https://lore.kernel.org/r/20190726005650.2566-2-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> [jgg: white space tuning] Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-25mm/hmm: comment on VM_FAULT_RETRY semantics in handle_mm_faultJason Gunthorpe
The magic dropping of mmap_sem when handle_mm_fault returns VM_FAULT_RETRY is rather subtile. Add a comment explaining it. Link: https://lore.kernel.org/r/20190724065258.16603-8-hch@lst.de Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> [hch: wrote a changelog] Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-07-25mm/hmm: always return EBUSY for invalid ranges in hmm_range_{fault,snapshot}Christoph Hellwig
We should not have two different error codes for the same condition. EAGAIN must be reserved for the FAULT_FLAG_ALLOW_RETRY retry case and signals to the caller that the mmap_sem has been unlocked. Use EBUSY for the !valid case so that callers can get the locking right. Link: https://lore.kernel.org/r/20190724065258.16603-2-hch@lst.de Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com> [jgg: elaborated commit message] Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-23percpu: fix typo in pcpu_setup_first_chunk() commentChristophe JAILLET
s/perpcu/percpu/ Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Dennis Zhou <dennis@kernel.org> [Dennis: updated title]
2019-07-22balloon: fix up commentsMichael S. Tsirkin
Lots of comments bitrotted. Fix them up. Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces) Reviewed-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Acked-by: Nadav Amit <namit@vmware.com>
2019-07-22mm/balloon_compaction: avoid duplicate page removalWei Wang
A #GP is reported in the guest when requesting balloon inflation via virtio-balloon. The reason is that the virtio-balloon driver has removed the page from its internal page list (via balloon_page_pop), but balloon_page_enqueue_one also calls "list_del" to do the removal. This is necessary when it's used from balloon_page_enqueue_list, but not from balloon_page_enqueue. Move list_del to balloon_page_enqueue, and update comments accordingly. Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces) Signed-off-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2019-07-22mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()Joerg Roedel
On x86-32 with PTI enabled, parts of the kernel page-tables are not shared between processes. This can cause mappings in the vmalloc/ioremap area to persist in some page-tables after the region is unmapped and released. When the region is re-used the processes with the old mappings do not fault in the new mappings but still access the old ones. This causes undefined behavior, in reality often data corruption, kernel oopses and panics and even spontaneous reboots. Fix this problem by activly syncing unmaps in the vmalloc/ioremap area to all page-tables in the system before the regions can be re-used. References: https://bugzilla.suse.com/show_bug.cgi?id=1118689 Fixes: 5d72b4fba40ef ('x86, mm: support huge I/O mapping capability I/F') Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20190719184652.11391-4-joro@8bytes.org
2019-07-19Merge branch 'work.mount0' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
2019-07-19Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge yet more updates from Andrew Morton: "The rest of MM and a kernel-wide procfs cleanup. Summary of the more significant patches: - Patch series "mm/memory_hotplug: Factor out memory block devicehandling", v3. David Hildenbrand. Some spring-cleaning of the memory hotplug code, notably in drivers/base/memory.c - "mm: thp: fix false negative of shmem vma's THP eligibility". Yang Shi. Fix /proc/pid/smaps output for THP pages used in shmem. - "resource: fix locking in find_next_iomem_res()" + 1. Nadav Amit. Bugfix and speedup for kernel/resource.c - Patch series "mm: Further memory block device cleanups", David Hildenbrand. More spring-cleaning of the memory hotplug code. - Patch series "mm: Sub-section memory hotplug support". Dan Williams. Generalise the memory hotplug code so that pmem can use it more completely. Then remove the hacks from the libnvdimm code which were there to work around the memory-hotplug code's constraints. - "proc/sysctl: add shared variables for range check", Matteo Croce. We have about 250 instances of int zero; ... .extra1 = &zero, in the tree. This is a tree-wide sweep to make all those private "zero"s and "one"s use global variables. Alas, it isn't practical to make those two global integers const" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (38 commits) proc/sysctl: add shared variables for range check mm: migrate: remove unused mode argument mm/sparsemem: cleanup 'section number' data types libnvdimm/pfn: stop padding pmem namespaces to section alignment libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields mm/devm_memremap_pages: enable sub-section remap mm: document ZONE_DEVICE memory-model implications mm/sparsemem: support sub-section hotplug mm/sparsemem: prepare for sub-section ranges mm: kill is_dev_zone() helper mm/hotplug: kill is_dev_zone() usage in __remove_pages() mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap() mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removal mm/sparsemem: add helpers track active portions of a section at boot mm/sparsemem: introduce a SECTION_IS_EARLY flag mm/sparsemem: introduce struct mem_section_usage drivers/base/memory.c: get rid of find_memory_block_hinted() mm/memory_hotplug: move and simplify walk_memory_blocks() mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of pfns mm: make register_mem_sect_under_node() static ...
2019-07-18mm: migrate: remove unused mode argumentKeith Busch
migrate_page_move_mapping() doesn't use the mode argument. Remove it and update callers accordingly. Link: http://lkml.kernel.org/r/20190508210301.8472-1-keith.busch@intel.com Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: cleanup 'section number' data typesDan Williams
David points out that there is a mixture of 'int' and 'unsigned long' usage for section number data types. Update the memory hotplug path to use 'unsigned long' consistently for section numbers. [akpm@linux-foundation.org: fix printk format] Link: http://lkml.kernel.org/r/156107543656.1329419.11505835211949439815.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: support sub-section hotplugDan Williams
The libnvdimm sub-system has suffered a series of hacks and broken workarounds for the memory-hotplug implementation's awkward section-aligned (128MB) granularity. For example the following backtrace is emitted when attempting arch_add_memory() with physical address ranges that intersect 'System RAM' (RAM) with 'Persistent Memory' (PMEM) within a given section: # cat /proc/iomem | grep -A1 -B1 Persistent\ Memory 100000000-1ffffffff : System RAM 200000000-303ffffff : Persistent Memory (legacy) 304000000-43fffffff : System RAM 440000000-23ffffffff : Persistent Memory 2400000000-43bfffffff : Persistent Memory 2400000000-43bfffffff : namespace2.0 WARNING: CPU: 38 PID: 928 at arch/x86/mm/init_64.c:850 add_pages+0x5c/0x60 [..] RIP: 0010:add_pages+0x5c/0x60 [..] Call Trace: devm_memremap_pages+0x460/0x6e0 pmem_attach_disk+0x29e/0x680 [nd_pmem] ? nd_dax_probe+0xfc/0x120 [libnvdimm] nvdimm_bus_probe+0x66/0x160 [libnvdimm] It was discovered that the problem goes beyond RAM vs PMEM collisions as some platform produce PMEM vs PMEM collisions within a given section. The libnvdimm workaround for that case revealed that the libnvdimm section-alignment-padding implementation has been broken for a long while. A fix for that long-standing breakage introduces as many problems as it solves as it would require a backward-incompatible change to the namespace metadata interpretation. Instead of that dubious route [1], address the root problem in the memory-hotplug implementation. Note that EEXIST is no longer treated as success as that is how sparse_add_section() reports subsection collisions, it was also obviated by recent changes to perform the request_region() for 'System RAM' before arch_add_memory() in the add_memory() sequence. [1] https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com [osalvador@suse.de: fix deactivate_section for early sections] Link: http://lkml.kernel.org/r/20190715081549.32577-2-osalvador@suse.de Link: http://lkml.kernel.org/r/156092354368.979959.6232443923440952359.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: prepare for sub-section rangesDan Williams
Prepare the memory hot-{add,remove} paths for handling sub-section ranges by plumbing the starting page frame and number of pages being handled through arch_{add,remove}_memory() to sparse_{add,remove}_one_section(). This is simply plumbing, small cleanups, and some identifier renames. No intended functional changes. Link: http://lkml.kernel.org/r/156092353780.979959.9713046515562743194.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm: kill is_dev_zone() helperDan Williams
Given there are no more usages of is_dev_zone() outside of 'ifdef CONFIG_ZONE_DEVICE' protection, kill off the compilation helper. Link: http://lkml.kernel.org/r/156092353211.979959.1489004866360828964.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: David Hildenbrand <david@redhat.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/hotplug: kill is_dev_zone() usage in __remove_pages()Dan Williams
The zone type check was a leftover from the cleanup that plumbed altmap through the memory hotplug path, i.e. commit da024512a1fa "mm: pass the vmem_altmap to arch_remove_memory and __remove_pages". Link: http://lkml.kernel.org/r/156092352642.979959.6664333788149363039.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap()Dan Williams
Allow sub-section sized ranges to be added to the memmap. populate_section_memmap() takes an explict pfn range rather than assuming a full section, and those parameters are plumbed all the way through to vmmemap_populate(). There should be no sub-section usage in current deployments. New warnings are added to clarify which memmap allocation paths are sub-section capable. Link: http://lkml.kernel.org/r/156092352058.979959.6551283472062305149.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit (git 2.34.1) at 2025-07-30 01:03:23 +0000