linux-kernel - [PATCH] netfs: Fix the netfs_folio tracepoint to handle NULL mapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <2917423.1727697556@warthog.procyon.org.uk>
Date: Mon, 30 Sep 2024 12:59:16 +0100
From: David Howells <dhowells@...hat.com>
To: Christian Brauner <brauner@...nel.org>
cc: dhowells@...hat.com, Jeff Layton <jlayton@...nel.org>,
    netfs@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
    linux-kernel@...r.kernel.org
Subject: [PATCH] netfs: Fix the netfs_folio tracepoint to handle NULL mapping

Fix the netfs_folio tracepoint to handle folios that have a NULL mapping
pointer.  In such a case, just substitute a zero inode number.

Fixes: c38f4e96e605 ("netfs: Provide func to copy data to pagecache for buffered write")
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Jeff Layton <jlayton@...nel.org>
cc: netfs@...ts.linux.dev
cc: linux-fsdevel@...r.kernel.org
---
 include/trace/events/netfs.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index 76bd42a96815..1d7c52821e55 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -448,7 +448,8 @@ TRACE_EVENT(netfs_folio,
 			     ),
 
 	    TP_fast_assign(
-		    __entry->ino = folio->mapping->host->i_ino;
+		    struct address_space *__m = READ_ONCE(folio->mapping);
+		    __entry->ino = __m ? __m->host->i_ino : 0;
 		    __entry->why = why;
 		    __entry->index = folio_index(folio);
 		    __entry->nr = folio_nr_pages(folio);