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authorAl Viro <viro@zeniv.linux.org.uk>2011-03-08 01:25:28 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2011-03-08 02:22:27 -0500
commitdfef6dcd35cb4a251f6322ca9b2c06f0bb1aa1f4 (patch)
tree65e8a25d4ed913658db35c4b97ab0a021c2124eb /include/linux/sysctl.h
parent1858efd471624ecb37e6b5462cab8076f47d1cee (diff)
unfuck proc_sysctl ->d_compare()
a) struct inode is not going to be freed under ->d_compare(); however, the thing PROC_I(inode)->sysctl points to just might. Fortunately, it's enough to make freeing that sucker delayed, provided that we don't step on its ->unregistering, clear the pointer to it in PROC_I(inode) before dropping the reference and check if it's NULL in ->d_compare(). b) I'm not sure that we *can* walk into NULL inode here (we recheck dentry->seq between verifying that it's still hashed / fetching dentry->d_inode and passing it to ->d_compare() and there's no negative hashed dentries in /proc/sys/*), but if we can walk into that, we really should not have ->d_compare() return 0 on it! Said that, I really suspect that this check can be simply killed. Nick? Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/sysctl.h')
-rw-r--r--include/linux/sysctl.h14
1 files changed, 10 insertions, 4 deletions
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 7bb5cb64f3b8..bb7c2b086fa4 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -25,6 +25,7 @@
25#include <linux/kernel.h> 25#include <linux/kernel.h>
26#include <linux/types.h> 26#include <linux/types.h>
27#include <linux/compiler.h> 27#include <linux/compiler.h>
28#include <linux/rcupdate.h>
28 29
29struct completion; 30struct completion;
30 31
@@ -1037,10 +1038,15 @@ struct ctl_table_root {
1037 struct ctl_table trees. */ 1038 struct ctl_table trees. */
1038struct ctl_table_header 1039struct ctl_table_header
1039{ 1040{
1040 struct ctl_table *ctl_table; 1041 union {
1041 struct list_head ctl_entry; 1042 struct {
1042 int used; 1043 struct ctl_table *ctl_table;
1043 int count; 1044 struct list_head ctl_entry;
1045 int used;
1046 int count;
1047 };
1048 struct rcu_head rcu;
1049 };
1044 struct completion *unregistering; 1050 struct completion *unregistering;
1045 struct ctl_table *ctl_table_arg; 1051 struct ctl_table *ctl_table_arg;
1046 struct ctl_table_root *root; 1052 struct ctl_table_root *root;