+ mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch added to -mm tree

+ mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: mm/mlock: fix potential imbalanced rlimit ucounts adjustment
has been added to the -mm tree.  Its filename is
     mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch

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------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: mm/mlock: fix potential imbalanced rlimit ucounts adjustment

user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
this by resetting allowed to 0.

Link: https://lkml.kernel.org/r/20220310132417.41189-1-linmiaohe@huawei.com
Fixes: 5ed44a401ddf ("do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mlock.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/mlock.c~mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment
+++ a/mm/mlock.c
@@ -839,6 +839,7 @@ int user_shm_lock(size_t size, struct uc
 	}
 	if (!get_ucounts(ucounts)) {
 		dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
+		allowed = 0;
 		goto out;
 	}
 	allowed = 1;
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-memremap-avoid-calling-kasan_remove_zero_shadow-for-device-private-memory.patch
filemap-remove-find_get_pages.patch
mm-writeback-minor-clean-up-for-highmem_dirtyable_memory.patch
mm-use-helper-function-range_in_vma.patch
mm-use-helper-macro-min-and-max-in-unmap_mapping_range_tree.patch
mm-mmap-remove-obsolete-comment-in-ksys_mmap_pgoff.patch
mm-sparse-make-mminit_validate_memmodel_limits-static.patch
mm-vmalloc-remove-unneeded-function-forward-declaration.patch
mm-mmzoneh-remove-unused-macros.patch
mm-memory-failurec-minor-clean-up-for-memory_failure_dev_pagemap.patch
mm-memory-failurec-catch-unexpected-efault-from-vma_address.patch
mm-memory-failurec-rework-the-signaling-logic-in-kill_proc.patch
mm-memory-failurec-fix-race-with-changing-page-more-robustly.patch
mm-memory-failurec-remove-pageslab-check-in-hwpoison_filter_dev.patch
mm-memory-failurec-rework-the-try_to_unmap-logic-in-hwpoison_user_mappings.patch
mm-memory-failurec-remove-obsolete-comment-in-__soft_offline_page.patch
mm-memory-failurec-remove-unnecessary-pagetranstail-check.patch
mm-hwpoison-inject-support-injecting-hwpoison-to-free-page.patch
mm-mlock-fix-potential-imbalanced-rlimit-ucounts-adjustment.patch
mm-hugetlb-use-helper-macro-__attr_rw.patch
mm-oom_kill-remove-unneeded-is_memcg_oom-check.patch
mm-ksm-use-helper-macro-__attr_rw.patch
mm-memory_hotplug-remove-obsolete-comment-of-__add_pages.patch
mm-memory_hotplug-avoid-calling-zone_intersects-for-zone_normal.patch
mm-memory_hotplug-clean-up-try_offline_node.patch
mm-memory_hotplug-fix-misplaced-comment-in-offline_pages.patch
mm-highmem-remove-unnecessary-done-label.patch
mm-hmmc-remove-unneeded-local-variable-ret.patch
kernel-ksysfsc-use-helper-macro-__attr_rw.patch
kernel-resource-fix-kfree-of-bootmem-memory-again.patch
mm-huge_memory-make-is_transparent_hugepage-static.patch