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From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] vfs: Fix fs_context logging when there's no log
Date: Tue, 21 Aug 2018 10:55:12 +0100	[thread overview]
Message-ID: <153484531201.1183.24087901695718354.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <153484529922.1183.17405985592221413059.stgit@warthog.procyon.org.uk>

If an fs_context-based mount is called from mount(2) or some other place
that doesn't set up the logging-through-fd, then under some circumstances
an oops will occur due to the log being unconditionally accessed in
logfc().

Fix this by checking whether there is a log structure before attempting to
access it

Fixes: 06b830edff9f ("vfs: Implement logging through fs_context")
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/fs_context.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/fs_context.c b/fs/fs_context.c
index 14921b2c1e42..053b8d0f11ea 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -416,7 +416,7 @@ void logfc(struct fs_context *fc, const char *fmt, ...)
 	if ((unsigned long)p >= (unsigned long)__start_rodata &&
 	    (unsigned long)p <  (unsigned long)__end_rodata)
 		goto const_string;
-	if (within_module_core((unsigned long)p, log->owner))
+	if (log && within_module_core((unsigned long)p, log->owner))
 		goto const_string;
 	q = kstrdup(p, GFP_KERNEL);
 	goto copied_string;


  parent reply	other threads:[~2018-08-21  9:55 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-21  9:54 vfs: Fixes/adjustments for mount API stuff David Howells
2018-08-21  9:55 ` [PATCH 1/6] vfs: Fix vfs_dup_fs_context() David Howells
2018-08-21  9:55 ` David Howells [this message]
2018-08-21  9:55 ` [PATCH 3/6] afs: Move the source fs parameter to the first position David Howells
2018-08-21  9:55 ` [PATCH 4/6] vfs: Pass path info fsinfo and rename get_fsinfo sb op to fsinfo David Howells
2018-08-21  9:55 ` [PATCH 5/6] vfs: Adjust fsinfo sample output David Howells
2018-08-21  9:55 ` [PATCH 6/6] proc: Set correct userns for new proc super created by a new pid_namespace David Howells

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