kernel.git/mm/mempolicy.c, branch linux-3.18.y

numa: change get_mempolicy() to use nr_node_ids instead of MAX_NUMNODES

2019-03-23T07:18:50Z

commit 050c17f239fd53adb55aa768d4f41bc76c0fe045 upstream. The system call, get_mempolicy() [1], passes an unsigned long *nodemask pointer and an unsigned long maxnode argument which specifies the length of the user's nodemask array in bits (which is rounded up). The manual page says that if the maxnode value is too small, get_mempolicy will return EINVAL but there is no system call to return this minimum value. To determine this value, some programs search /proc//status for a line starting with "Mems_allowed:" and use the number of digits in the mask to determine the minimum value. A recent change to the way this line is formatted [2] causes these programs to compute a value less than MAX_NUMNODES so get_mempolicy() returns EINVAL. Change get_mempolicy(), the older compat version of get_mempolicy(), and the copy_nodes_to_user() function to use nr_node_ids instead of MAX_NUMNODES, thus preserving the defacto method of computing the minimum size for the nodemask array and the maxnode argument. [1] http://man7.org/linux/man-pages/man2/get_mempolicy.2.html [2] https://lore.kernel.org/lkml/1545405631-6808-1-git-send-email-longman@redhat.com Link: http://lkml.kernel.org/r/20190211180245.22295-1-rcampbell@nvidia.com Fixes: 4fb8e5b89bcbbbb ("include/linux/nodemask.h: use nr_node_ids (not MAX_NUMNODES) in __nodemask_pr_numnodes()") Signed-off-by: Ralph Campbell Suggested-by: Alexander Duyck Cc: Waiman Long Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/mempolicy.c: avoid use uninitialized preferred_node

2018-05-30T05:47:37Z

[ Upstream commit 8970a63e965b43288c4f5f40efbc2bbf80de7f16 ] Alexander reported a use of uninitialized memory in __mpol_equal(), which is caused by incorrect use of preferred_node. When mempolicy in mode MPOL_PREFERRED with flags MPOL_F_LOCAL, it uses numa_node_id() instead of preferred_node, however, __mpol_equal() uses preferred_node without checking whether it is MPOL_F_LOCAL or not. [akpm@linux-foundation.org: slight comment tweak] Link: http://lkml.kernel.org/r/4ebee1c2-57f6-bcb8-0e2d-1833d1ee0bb7@huawei.com Fixes: fc36b8d3d819 ("mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy") Signed-off-by: Yisheng Xie Reported-by: Alexander Potapenko Tested-by: Alexander Potapenko Reviewed-by: Andrew Morton Cc: Dmitriy Vyukov Cc: Vlastimil Babka Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm/mempolicy: add nodes_empty check in SYSC_migrate_pages

2018-05-30T05:47:31Z

[ Upstream commit 0486a38bcc4749808edbc848f1bcf232042770fc ] As in manpage of migrate_pages, the errno should be set to EINVAL when none of the node IDs specified by new_nodes are on-line and allowed by the process's current cpuset context, or none of the specified nodes contain memory. However, when test by following case: new_nodes = 0; old_nodes = 0xf; ret = migrate_pages(pid, old_nodes, new_nodes, MAX); The ret will be 0 and no errno is set. As the new_nodes is empty, we should expect EINVAL as documented. To fix the case like above, this patch check whether target nodes AND current task_nodes is empty, and then check whether AND node_states[N_MEMORY] is empty. Link: http://lkml.kernel.org/r/1510882624-44342-4-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Chris Salls Cc: Christopher Lameter Cc: David Rientjes Cc: Ingo Molnar Cc: Naoya Horiguchi Cc: Tan Xiaojun Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm/mempolicy: fix the check of nodemask from user

2018-05-30T05:47:31Z

[ Upstream commit 56521e7a02b7b84a5e72691a1fb15570e6055545 ] As Xiaojun reported the ltp of migrate_pages01 will fail on arm64 system which has 4 nodes[0...3], all have memory and CONFIG_NODES_SHIFT=2: migrate_pages01 0 TINFO : test_invalid_nodes migrate_pages01 14 TFAIL : migrate_pages_common.c:45: unexpected failure - returned value = 0, expected: -1 migrate_pages01 15 TFAIL : migrate_pages_common.c:55: call succeeded unexpectedly In this case the test_invalid_nodes of migrate_pages01 will call: SYSC_migrate_pages as: migrate_pages(0, , {0x0000000000000001}, 64, , {0x0000000000000010}, 64) = 0 The new nodes specifies one or more node IDs that are greater than the maximum supported node ID, however, the errno is not set to EINVAL as expected. As man pages of set_mempolicy[1], mbind[2], and migrate_pages[3] mentioned, when nodemask specifies one or more node IDs that are greater than the maximum supported node ID, the errno should set to EINVAL. However, get_nodes only check whether the part of bits [BITS_PER_LONG*BITS_TO_LONGS(MAX_NUMNODES), maxnode) is zero or not, and remain [MAX_NUMNODES, BITS_PER_LONG*BITS_TO_LONGS(MAX_NUMNODES) unchecked. This patch is to check the bits of [MAX_NUMNODES, maxnode) in get_nodes to let migrate_pages set the errno to EINVAL when nodemask specifies one or more node IDs that are greater than the maximum supported node ID, which follows the manpage's guide. [1] http://man7.org/linux/man-pages/man2/set_mempolicy.2.html [2] http://man7.org/linux/man-pages/man2/mbind.2.html [3] http://man7.org/linux/man-pages/man2/migrate_pages.2.html Link: http://lkml.kernel.org/r/1510882624-44342-3-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie Reported-by: Tan Xiaojun Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Chris Salls Cc: Christopher Lameter Cc: David Rientjes Cc: Ingo Molnar Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm/mempolicy: fix use after free when calling get_mempolicy

2017-08-25T00:00:10Z

commit 73223e4e2e3867ebf033a5a8eb2e5df0158ccc99 upstream. I hit a use after free issue when executing trinity and repoduced it with KASAN enabled. The related call trace is as follows. BUG: KASan: use after free in SyS_get_mempolicy+0x3c8/0x960 at addr ffff8801f582d766 Read of size 2 by task syz-executor1/798 INFO: Allocated in mpol_new.part.2+0x74/0x160 age=3 cpu=1 pid=799 __slab_alloc+0x768/0x970 kmem_cache_alloc+0x2e7/0x450 mpol_new.part.2+0x74/0x160 mpol_new+0x66/0x80 SyS_mbind+0x267/0x9f0 system_call_fastpath+0x16/0x1b INFO: Freed in __mpol_put+0x2b/0x40 age=4 cpu=1 pid=799 __slab_free+0x495/0x8e0 kmem_cache_free+0x2f3/0x4c0 __mpol_put+0x2b/0x40 SyS_mbind+0x383/0x9f0 system_call_fastpath+0x16/0x1b INFO: Slab 0xffffea0009cb8dc0 objects=23 used=8 fp=0xffff8801f582de40 flags=0x200000000004080 INFO: Object 0xffff8801f582d760 @offset=5984 fp=0xffff8801f582d600 Bytes b4 ffff8801f582d750: ae 01 ff ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ Object ffff8801f582d760: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff8801f582d770: 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkk. Redzone ffff8801f582d778: bb bb bb bb bb bb bb bb ........ Padding ffff8801f582d8b8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Memory state around the buggy address: ffff8801f582d600: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801f582d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801f582d700: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fc !shared memory policy is not protected against parallel removal by other thread which is normally protected by the mmap_sem. do_get_mempolicy, however, drops the lock midway while we can still access it later. Early premature up_read is a historical artifact from times when put_user was called in this path see https://lwn.net/Articles/124754/ but that is gone since 8bccd85ffbaf ("[PATCH] Implement sys_* do_* layering in the memory policy layer."). but when we have the the current mempolicy ref count model. The issue was introduced accordingly. Fix the issue by removing the premature release. Link: http://lkml.kernel.org/r/1502950924-27521-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang Acked-by: Michal Hocko Cc: Minchan Kim Cc: Vlastimil Babka Cc: David Rientjes Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/mempolicy.c: fix error handling in set_mempolicy and mbind.

2017-04-22T05:15:06Z

commit cf01fb9985e8deb25ccf0ea54d916b8871ae0e62 upstream. In the case that compat_get_bitmap fails we do not want to copy the bitmap to the user as it will contain uninitialized stack data and leak sensitive data. Signed-off-by: Chris Salls Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm, numa: really disable NUMA balancing by default on single node machines

2015-06-10T17:42:34Z

[ Upstream commit b0dc2b9bb4ab782115b964310518ee0b17784277 ] NUMA balancing is meant to be disabled by default on UMA machines but the check is using nr_node_ids (highest node) instead of num_online_nodes (online nodes). The consequences are that a UMA machine with a node ID of 1 or higher will enable NUMA balancing. This will incur useless overhead due to minor faults with the impact depending on the workload. These are the impact on the stats when running a kernel build on a single node machine whose node ID happened to be 1: vanilla patched NUMA base PTE updates 5113158 0 NUMA huge PMD updates 643 0 NUMA page range updates 5442374 0 NUMA hint faults 2109622 0 NUMA hint local faults 2109622 0 NUMA hint local percent 100 100 NUMA pages migrated 0 0 Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: [3.8+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm: mempolicy: skip inaccessible VMAs when setting MPOL_MF_LAZY

2014-10-10T02:26:02Z

PROT_NUMA VMAs are skipped to avoid problems distinguishing between present, prot_none and special entries. MPOL_MF_LAZY is not visible from userspace since commit a720094ded8c ("mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now") but it should still skip VMAs the same way task_numa_work does. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Acked-by: Hugh Dickins Acked-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mempolicy: unexport get_vma_policy() and remove its "task" arg

2014-10-10T02:25:56Z

- get_vma_policy(task) is not safe if task != current, remove this argument. - get_vma_policy() no longer has callers outside of mempolicy.c, make it static. Signed-off-by: Oleg Nesterov Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Hugh Dickins Cc: Andi Kleen Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mempolicy: kill do_set_mempolicy()->down_write(&mm->mmap_sem)

2014-10-10T02:25:56Z

Remove down_write(&mm->mmap_sem) in do_set_mempolicy(). This logic was never correct and it is no longer needed, see the previous patch. Signed-off-by: Oleg Nesterov Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Hugh Dickins Cc: Andi Kleen Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds