On Thu, Jul 4, 2019 at 2:06 PM akpm@linux-foundation.org wrote:
The patch titled Subject: mm/z3fold.c: lock z3fold page before __SetPageMovable() has been added to the -mm tree. Its filename is mm-z3foldc-lock-z3fold-page-before-__setpagemovable.patch
This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-z3foldc-lock-z3fold-page-before-... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-z3foldc-lock-z3fold-page-before-...
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From: Henry Burns henryburns@google.com Subject: mm/z3fold.c: lock z3fold page before __SetPageMovable()
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.
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 henryburns@google.com Suggested-by: Vitaly Wool vitalywool@gmail.com Acked-by: Vitaly Wool vitalywool@gmail.com Acked-by: David Rientjes rientjes@google.com Cc: Shakeel Butt shakeelb@google.com Cc: Vitaly Vul vitaly.vul@sony.com Cc: Mike Rapoport rppt@linux.vnet.ibm.com Cc: Xidong Wang wangxidong_97@163.com Cc: Jonathan Adams jwadams@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
mm/z3fold.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
--- a/mm/z3fold.c~mm-z3foldc-lock-z3fold-page-before-__setpagemovable +++ a/mm/z3fold.c @@ -924,7 +924,16 @@ retry: set_bit(PAGE_HEADLESS, &page->private); goto headless; }
__SetPageMovable(page, pool->inode->i_mapping);
if (can_sleep) {lock_page(page);__SetPageMovable(page, pool->inode->i_mapping);unlock_page(page);} else {if (!trylock_page(page)) {
Oops, the above should be just trylock_page() without the '!'. Andrew, can you please fix this in-place or do you want a new version to be posted.
__SetPageMovable(page, pool->inode->i_mapping);unlock_page(page);}} z3fold_page_lock(zhdr);found: @@ -1331,6 +1340,7 @@ static int z3fold_page_migrate(struct ad
VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page);
VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); zhdr = page_address(page); pool = zhdr_to_pool(zhdr);_
Patches currently in -mm which might be from henryburns@google.com are
mm-z3foldc-lock-z3fold-page-before-__setpagemovable.patch mm-z3fold-fix-z3fold_buddy_slots-use-after-free.patch