From: Ryusuke Konishi Date: Fri, 31 Aug 2007 06:56:33 +0000 (-0700) Subject: eCryptfs: fix possible fault in ecryptfs_sync_page X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2aeb3db17fc33443d21b11d7121c5627d55717c6;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git eCryptfs: fix possible fault in ecryptfs_sync_page This will avoid a possible fault in ecryptfs_sync_page(). In the function, eCryptfs calls sync_page() method of a lower filesystem without checking its existence. However, there are many filesystems that don't have this method including network filesystems such as NFS, AFS, and so forth. They may fail when an eCryptfs page is waiting for lock. Signed-off-by: Ryusuke Konishi Acked-by: Michael Halcrow Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index e4ab7bc14efe..fd3f94d4a668 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -834,7 +834,8 @@ static void ecryptfs_sync_page(struct page *page) ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n"); return; } - lower_page->mapping->a_ops->sync_page(lower_page); + if (lower_page->mapping->a_ops->sync_page) + lower_page->mapping->a_ops->sync_page(lower_page); ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", lower_page->index); unlock_page(lower_page);