linux-kernel - [PATCH] kernfs: handle poll correctly on 'direct

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]

Date:	Mon, 16 Mar 2015 10:44:52 +1100
From:	NeilBrown <neilb@...e.de>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Tejun Heo <tj@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Prakash Punnoor <prakash@...noor.de>,
	Torsten Kaiser <just.for.lkml@...glemail.com>,
	linux RAID <linux-raid@...r.kernel.org>
Subject: [PATCH] kernfs: handle poll correctly on 'direct_read' files.



Kernfs supports two styles of read: direct_read and seqfile_read.

The latter supports 'poll' correctly thanks to the update of
'->event' in kernfs_seq_show.
The former does not as '->event' is never updated on a read.

So add an appropriate update in kernfs_file_direct_read().

This was noticed because some 'md' sysfs attributes were
recently changed to use direct reads.

Reported-by: Prakash Punnoor <prakash@...noor.de>
Reported-by: Torsten Kaiser <just.for.lkml@...glemail.com>
Fixes: 750f199ee8b578062341e6ddfe36c59ac8ff2dcb
Signed-off-by: NeilBrown <neilb@...e.de>

diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index b684e8a132e6..2bacb9988566 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -207,6 +207,7 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,
 		goto out_free;
 	}
 
+	of->event = atomic_read(&of->kn->attr.open->event);
 	ops = kernfs_ops(of->kn);
 	if (ops->read)
 		len = ops->read(of, buf, len, *ppos);

Content of type "application/pgp-signature" skipped