From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D1D533DEFE; Mon, 20 Apr 2026 16:04:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701049; cv=none; b=sKiq6L9I3w15Idvs5dIJFbNgkPwNw6iaO2gqqbVy6+cjDVCo8piEYhQOsQb5OIi61nM9kHs5YEip+uFBSt+uaOXRoSVXltv/yOREAuxK47Ex8YDnsks9ICcFoupWmzp5iDYx3GexrAaSWvTlC4rh6KLehkMMp6w2wwIU0CYK/WU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701049; c=relaxed/simple; bh=vDvzrfkfxozNVLifbDNP7JFnR07FOJsN0KoW5tK+6TQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MGFMYDByj+r/gF84NG73wbIpGE5P/RR1t6IWn5vmTzo2f4zP+SJRnf2C8ZWKPzfWofBabUiECgCxULAiWtGJQitKQ4V6S1wmbLBtsAFIEPiRQOkMtXUCBvqWTSA/w8e5as6Ltk3BTVF/+O+RCB99j6ymIV0hHBrwtg9YWOU37GU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oDTk5OTn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oDTk5OTn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A188DC19425; Mon, 20 Apr 2026 16:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776701049; bh=vDvzrfkfxozNVLifbDNP7JFnR07FOJsN0KoW5tK+6TQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oDTk5OTnGRqoLu34D0o9Xfa8Hmq9Wq1poDPomY5cAa6v3gpHj35c570oR10rN8uoV i9eEI9DBe9tDCS1zb0mChFWKGZ6KP593ua5lsrVXiH4qgWeA3qu7KlxAPeopWtZVbE MmtI4TG5SE5ghlI/tcTT4FGOE0SugOtxz4VMhdCg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tejas Bharambe , syzbot+a49010a0e8fcdeea075f@syzkaller.appspotmail.com, Joseph Qi , Mark Fasheh , Joel Becker , Junxiao Bi , Changwei Ge , Jun Piao , Heming Zhao , Andrew Morton Subject: [PATCH 6.18 161/198] ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY Date: Mon, 20 Apr 2026 17:42:20 +0200 Message-ID: <20260420153941.409428745@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tejas Bharambe commit 7de554cabf160e331e4442e2a9ad874ca9875921 upstream. filemap_fault() may drop the mmap_lock before returning VM_FAULT_RETRY, as documented in mm/filemap.c: "If our return value has VM_FAULT_RETRY set, it's because the mmap_lock may be dropped before doing I/O or by lock_folio_maybe_drop_mmap()." When this happens, a concurrent munmap() can call remove_vma() and free the vm_area_struct via RCU. The saved 'vma' pointer in ocfs2_fault() then becomes a dangling pointer, and the subsequent trace_ocfs2_fault() call dereferences it -- a use-after-free. Fix this by saving ip_blkno as a plain integer before calling filemap_fault(), and removing vma from the trace event. Since ip_blkno is copied by value before the lock can be dropped, it remains valid regardless of what happens to the vma or inode afterward. Link: https://lkml.kernel.org/r/20260410083816.34951-1-tejas.bharambe@outlook.com Fixes: 614a9e849ca6 ("ocfs2: Remove FILE_IO from masklog.") Signed-off-by: Tejas Bharambe Reported-by: syzbot+a49010a0e8fcdeea075f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a49010a0e8fcdeea075f Suggested-by: Joseph Qi Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/mmap.c | 7 +++---- fs/ocfs2/ocfs2_trace.h | 10 ++++------ 2 files changed, 7 insertions(+), 10 deletions(-) --- a/fs/ocfs2/mmap.c +++ b/fs/ocfs2/mmap.c @@ -30,7 +30,8 @@ static vm_fault_t ocfs2_fault(struct vm_fault *vmf) { - struct vm_area_struct *vma = vmf->vma; + unsigned long long ip_blkno = + OCFS2_I(file_inode(vmf->vma->vm_file))->ip_blkno; sigset_t oldset; vm_fault_t ret; @@ -38,11 +39,9 @@ static vm_fault_t ocfs2_fault(struct vm_ ret = filemap_fault(vmf); ocfs2_unblock_signals(&oldset); - trace_ocfs2_fault(OCFS2_I(vma->vm_file->f_mapping->host)->ip_blkno, - vma, vmf->page, vmf->pgoff); + trace_ocfs2_fault(ip_blkno, vmf->page, vmf->pgoff); return ret; } - static vm_fault_t __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh, struct folio *folio) { --- a/fs/ocfs2/ocfs2_trace.h +++ b/fs/ocfs2/ocfs2_trace.h @@ -1246,22 +1246,20 @@ TRACE_EVENT(ocfs2_write_end_inline, TRACE_EVENT(ocfs2_fault, TP_PROTO(unsigned long long ino, - void *area, void *page, unsigned long pgoff), - TP_ARGS(ino, area, page, pgoff), + void *page, unsigned long pgoff), + TP_ARGS(ino, page, pgoff), TP_STRUCT__entry( __field(unsigned long long, ino) - __field(void *, area) __field(void *, page) __field(unsigned long, pgoff) ), TP_fast_assign( __entry->ino = ino; - __entry->area = area; __entry->page = page; __entry->pgoff = pgoff; ), - TP_printk("%llu %p %p %lu", - __entry->ino, __entry->area, __entry->page, __entry->pgoff) + TP_printk("%llu %p %lu", + __entry->ino, __entry->page, __entry->pgoff) ); /* End of trace events for fs/ocfs2/mmap.c. */