From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+mH1ish1NUV6VJ+M+U8/V6M6MAulA725IY1WAYPYKrN1xhpDmXoVDEnI0kzhjHlQfrKPAh ARC-Seal: i=1; a=rsa-sha256; t=1524406497; cv=none; d=google.com; s=arc-20160816; b=tS/epmJwFLH8qvuCwMQAWStwCMKRYU/0omVWsUXHBSpDJJDnj3AsfkQBPV/Jojd8b2 F3C1Rjkm4bCLJ9UJvsH1WuSWYzpI88sEv+Mq9kN90grZfLbCqksdCItClfO8erZjVl2d hxvTN2aK7AVTzEN2YrYPwII9WVa1zM6+xtBe22BHwJ5AXcr7UHrd2JFjVusrOyCtJ2nH HeyJXQCx+o7pQSqMdYT2veBOTLw262s0cRjsRDGFQtPEDSnucsqjho3OV4bbtjTY6lV2 cphXRJrEHGtSP+P9VR9qB6bkDUJ42jAMvYETyArBuOI5fG0tlTOvFksNLph84xJqk0Xf cB6g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=D5P3XLiQRbSTWX79wk5qi60oaUnuF4OlWhp7Ecd0yYs=; b=dYYy3LetX4iX0WSt+S+0tSCc+0iqgPhXj2nJ2qNc9ptXrz7sKYhW5W8vAm+xqBHP4i fcktVkBz8LkYZFEA7pDJutBqO3k7MhQKLif977FWMMQlqmWrkRpNVtkFTUh1LHJQwJYe OgkzJIWJCMNTiPgODNYZ4WcT5o8KCDgWxz7VtPsyzp8rdJVzxMm2kdpVnbxxUfh3VB7Y iO+XNptmK8yknMH+i3A3oadoSauvXF27udPQrWb9MvzKB+dxcXoDVtZ8993GyL1ngb4C BkqiCCXKDDJsy2TK42ib93SdQv/hE0w4GBIaMl78W0arpxzMEZuHxHIeH8Frt/3d4iiq BoYQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Wilcox , Chris Fries , Johannes Weiner , Michal Hocko , Jan Kara , Andrew Morton , Linus Torvalds Subject: [PATCH 4.9 92/95] mm/filemap.c: fix NULL pointer in page_cache_tree_insert() Date: Sun, 22 Apr 2018 15:54:01 +0200 Message-Id: <20180422135214.183266218@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135210.432103639@linuxfoundation.org> References: <20180422135210.432103639@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598455322200106051?= X-GMAIL-MSGID: =?utf-8?q?1598456067648681014?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox commit abc1be13fd113ddef5e2d807a466286b864caed3 upstream. f2fs specifies the __GFP_ZERO flag for allocating some of its pages. Unfortunately, the page cache also uses the mapping's GFP flags for allocating radix tree nodes. It always masked off the __GFP_HIGHMEM flag, and masks off __GFP_ZERO in some paths, but not all. That causes radix tree nodes to be allocated with a NULL list_head, which causes backtraces like: __list_del_entry+0x30/0xd0 list_lru_del+0xac/0x1ac page_cache_tree_insert+0xd8/0x110 The __GFP_DMA and __GFP_DMA32 flags would also be able to sneak through if they are ever used. Fix them all by using GFP_RECLAIM_MASK at the innermost location, and remove it from earlier in the callchain. Link: http://lkml.kernel.org/r/20180411060320.14458-2-willy@infradead.org Fixes: 449dd6984d0e ("mm: keep page cache radix tree nodes in check") Signed-off-by: Matthew Wilcox Reported-by: Chris Fries Debugged-by: Minchan Kim Acked-by: Johannes Weiner Acked-by: Michal Hocko Reviewed-by: Jan Kara Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/filemap.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/mm/filemap.c +++ b/mm/filemap.c @@ -616,7 +616,7 @@ int replace_page_cache_page(struct page VM_BUG_ON_PAGE(!PageLocked(new), new); VM_BUG_ON_PAGE(new->mapping, new); - error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + error = radix_tree_preload(gfp_mask & GFP_RECLAIM_MASK); if (!error) { struct address_space *mapping = old->mapping; void (*freepage)(struct page *); @@ -672,7 +672,7 @@ static int __add_to_page_cache_locked(st return error; } - error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM); + error = radix_tree_maybe_preload(gfp_mask & GFP_RECLAIM_MASK); if (error) { if (!huge) mem_cgroup_cancel_charge(page, memcg, false); @@ -1247,8 +1247,7 @@ no_page: if (fgp_flags & FGP_ACCESSED) __SetPageReferenced(page); - err = add_to_page_cache_lru(page, mapping, offset, - gfp_mask & GFP_RECLAIM_MASK); + err = add_to_page_cache_lru(page, mapping, offset, gfp_mask); if (unlikely(err)) { put_page(page); page = NULL; @@ -1996,7 +1995,7 @@ static int page_cache_read(struct file * if (!page) return -ENOMEM; - ret = add_to_page_cache_lru(page, mapping, offset, gfp_mask & GFP_KERNEL); + ret = add_to_page_cache_lru(page, mapping, offset, gfp_mask); if (ret == 0) ret = mapping->a_ops->readpage(file, page); else if (ret == -EEXIST)