The patch titled
knfsd: use a spinlock to protect sk_info_authunix
has been added to the -mm tree. Its filename is
knfsd-use-a-spinlock-to-protect-sk_info_authunix.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: knfsd: use a spinlock to protect sk_info_authunix
From: NeilBrown <neilb@xxxxxxx>
sk_info_authunix is not being protected properly so the object that it
points to can be cache_put twice, leading to corruption.
We borrow svsk->sk_defer_lock to provide the protection. We should
probably rename that lock to have a more generic name - later.
Thanks to Gabriel for reporting this.
Cc: Greg Banks <gnb@xxxxxxxxxxxxxxxxx>
Cc: Gabriel Barazer <gabriel@xxxxxxxx>
Signed-off-by: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
net/sunrpc/svcauth_unix.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff -puN net/sunrpc/svcauth_unix.c~knfsd-use-a-spinlock-to-protect-sk_info_authunix net/sunrpc/svcauth_unix.c
--- a/net/sunrpc/svcauth_unix.c~knfsd-use-a-spinlock-to-protect-sk_info_authunix
+++ a/net/sunrpc/svcauth_unix.c
@@ -383,7 +383,10 @@ void svcauth_unix_purge(void)
static inline struct ip_map *
ip_map_cached_get(struct svc_rqst *rqstp)
{
- struct ip_map *ipm = rqstp->rq_sock->sk_info_authunix;
+ struct ip_map *ipm;
+ struct svc_sock *svsk = rqstp->rq_sock;
+ spin_lock_bh(&svsk->sk_defer_lock);
+ ipm = svsk->sk_info_authunix;
if (ipm != NULL) {
if (!cache_valid(&ipm->h)) {
/*
@@ -391,12 +394,14 @@ ip_map_cached_get(struct svc_rqst *rqstp
* remembered, e.g. by a second mount from the
* same IP address.
*/
- rqstp->rq_sock->sk_info_authunix = NULL;
+ svsk->sk_info_authunix = NULL;
+ spin_unlock_bh(&svsk->sk_defer_lock);
cache_put(&ipm->h, &ip_map_cache);
return NULL;
}
cache_get(&ipm->h);
}
+ spin_unlock_bh(&svsk->sk_defer_lock);
return ipm;
}
@@ -405,9 +410,15 @@ ip_map_cached_put(struct svc_rqst *rqstp
{
struct svc_sock *svsk = rqstp->rq_sock;
- if (svsk->sk_sock->type == SOCK_STREAM && svsk->sk_info_authunix == NULL)
- svsk->sk_info_authunix = ipm; /* newly cached, keep the reference */
- else
+ spin_lock_bh(&svsk->sk_defer_lock);
+ if (svsk->sk_sock->type == SOCK_STREAM &&
+ svsk->sk_info_authunix == NULL) {
+ /* newly cached, keep the reference */
+ svsk->sk_info_authunix = ipm;
+ ipm = NULL;
+ }
+ spin_unlock_bh(&svsk->sk_defer_lock);
+ if (ipm)
cache_put(&ipm->h, &ip_map_cache);
}
_
Patches currently in -mm which might be from neilb@xxxxxxx are
origin.patch
knfsd-use-a-spinlock-to-protect-sk_info_authunix.patch
device_schedule_callback-needs-a-module-reference.patch
device_schedule_callback-needs-a-module-reference-fix.patch
sunrpc-cleanup-use-seq_release_private-where-appropriate.patch
slub-core-fix-kmem_cache_destroy.patch
fix-quadratic-behavior-of-shrink_dcache_parent.patch
fix-__d_path-for-lazy-unmounts-and-make-it-unambiguous.patch
nlmclnt_recovery-dont-use-clone_sighand.patch
the-nfsv2-nfsv3-server-does-not-handle-zero-length-write.patch
readahead-nfsd-case.patch
drivers-mdc-use-array_size-macro-when-appropriate.patch
md-cleanup-use-seq_release_private-where-appropriate.patch
md-dm-reduce-stack-usage-with-stacked-block-devices.patch
-
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