From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, almasrymina@google.com,
jthoughton@google.com, linux-mm@kvack.org,
mike.kravetz@oracle.com, mm-commits@vger.kernel.org,
stable@vger.kernel.org, torvalds@linux-foundation.org,
weixugc@google.com
Subject: [patch 10/15] hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Date: Fri, 19 Nov 2021 16:43:43 -0800 [thread overview]
Message-ID: <20211120004343.akzlmXMvc%akpm@linux-foundation.org> (raw)
In-Reply-To: <20211119164248.50feee07c5d2cc6cc4addf97@linux-foundation.org>
From: Mina Almasry <almasrymina@google.com>
Subject: hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we
bail out using "goto out_release_unlock;" in the cases where idx >= size,
or !huge_pte_none(), the code will detect that new_pagecache_page ==
false, and so call restore_reserve_on_error(). In this case I see
restore_reserve_on_error() delete the reservation, and the following call
to remove_inode_hugepages() will increment h->resv_hugepages causing a
100% reproducible leak.
We should treat the is_continue case similar to adding a page into the
pagecache and set new_pagecache_page to true, to indicate that there is no
reservation to restore on the error path, and we need not call
restore_reserve_on_error(). Rename new_pagecache_page to
page_in_pagecache to make that clear.
Link: https://lkml.kernel.org/r/20211117193825.378528-1-almasrymina@google.com
Fixes: c7b1850dfb41 ("hugetlb: don't pass page cache pages to restore_reserve_on_error")
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reported-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/hugetlb.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/mm/hugetlb.c~hugetlb-userfaultfd-fix-reservation-restore-on-userfaultfd-error
+++ a/mm/hugetlb.c
@@ -5736,13 +5736,14 @@ int hugetlb_mcopy_atomic_pte(struct mm_s
int ret = -ENOMEM;
struct page *page;
int writable;
- bool new_pagecache_page = false;
+ bool page_in_pagecache = false;
if (is_continue) {
ret = -EFAULT;
page = find_lock_page(mapping, idx);
if (!page)
goto out;
+ page_in_pagecache = true;
} else if (!*pagep) {
/* If a page already exists, then it's UFFDIO_COPY for
* a non-missing case. Return -EEXIST.
@@ -5830,7 +5831,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_s
ret = huge_add_to_page_cache(page, mapping, idx);
if (ret)
goto out_release_nounlock;
- new_pagecache_page = true;
+ page_in_pagecache = true;
}
ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
@@ -5894,7 +5895,7 @@ out_release_unlock:
if (vm_shared || is_continue)
unlock_page(page);
out_release_nounlock:
- if (!new_pagecache_page)
+ if (!page_in_pagecache)
restore_reserve_on_error(h, dst_vma, dst_addr, page);
put_page(page);
goto out;
_
next prev parent reply other threads:[~2021-11-20 0:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 0:42 incoming Andrew Morton
2021-11-20 0:43 ` [patch 01/15] mm/swap.c:put_pages_list(): reinitialise the page list Andrew Morton
2021-11-20 0:43 ` [patch 02/15] ipc: WARN if trying to remove ipc object which is absent Andrew Morton
2021-11-20 0:43 ` [patch 03/15] shm: extend forced shm destroy to support objects from several IPC nses Andrew Morton
2021-11-20 0:43 ` [patch 04/15] mm: emit the "free" trace report before freeing memory in kmem_cache_free() Andrew Morton
2021-11-20 0:43 ` [patch 05/15] hexagon: export raw I/O routines for modules Andrew Morton
2021-11-20 0:43 ` [patch 06/15] hexagon: clean up timer-regs.h Andrew Morton
2021-11-20 0:43 ` [patch 07/15] hexagon: ignore vmlinux.lds Andrew Morton
2021-11-20 0:43 ` [patch 08/15] mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag Andrew Morton
2021-11-20 0:43 ` [patch 09/15] hugetlb: fix hugetlb cgroup refcounting during mremap Andrew Morton
2021-11-20 0:43 ` Andrew Morton [this message]
2021-11-20 0:43 ` [patch 11/15] kasan: test: silence intentional read overflow warnings Andrew Morton
2021-11-20 0:43 ` [patch 12/15] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation Andrew Morton
2021-11-20 0:43 ` [patch 13/15] mm/damon/dbgfs: fix missed use of damon_dbgfs_lock Andrew Morton
2021-11-20 0:43 ` [patch 14/15] kmap_local: don't assume kmap PTEs are linear arrays in memory Andrew Morton
2021-11-20 0:43 ` [patch 15/15] proc/vmcore: fix clearing user buffer by properly using clear_user() Andrew Morton
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