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authorAlexey Kuznetsov <kuznet@ms2.inr.ac.ru>2006-12-14 22:28:51 +0100
committerAdrian Bunk <bunk@stusta.de>2006-12-14 22:28:51 +0100
commit2a9d7dbf7566a36221b4066e57f4c3212bff1ef0 (patch)
tree5d77b44e9394bd0e10b66681792af18d52540636
parent594834bc754f243ddc3d16b9cac354702101c719 (diff)
[IPV4]: severe locking bug in fib_semantics.c
Found in 2.4 by Yixin Pan <yxpan@hotmail.com>. > When I read fib_semantics.c of Linux-2.4.32, write_lock(&fib_info_lock) = > is used in fib_release_info() instead of write_lock_bh(&fib_info_lock). = > Is the following case possible: a BH interrupts fib_release_info() while = > holding the write lock, and calls ip_check_fib_default() which calls = > read_lock(&fib_info_lock), and spin forever. Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: Adrian Bunk <bunk@stusta.de>
-rw-r--r--net/ipv4/fib_semantics.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 0f4145babb14..1de08c18637b 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -160,7 +160,7 @@ void free_fib_info(struct fib_info *fi)
void fib_release_info(struct fib_info *fi)
{
- write_lock(&fib_info_lock);
+ write_lock_bh(&fib_info_lock);
if (fi && --fi->fib_treeref == 0) {
hlist_del(&fi->fib_hash);
if (fi->fib_prefsrc)
@@ -173,7 +173,7 @@ void fib_release_info(struct fib_info *fi)
fi->fib_dead = 1;
fib_info_put(fi);
}
- write_unlock(&fib_info_lock);
+ write_unlock_bh(&fib_info_lock);
}
static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
@@ -599,7 +599,7 @@ static void fib_hash_move(struct hlist_head *new_info_hash,
unsigned int old_size = fib_hash_size;
unsigned int i, bytes;
- write_lock(&fib_info_lock);
+ write_lock_bh(&fib_info_lock);
old_info_hash = fib_info_hash;
old_laddrhash = fib_info_laddrhash;
fib_hash_size = new_size;
@@ -640,7 +640,7 @@ static void fib_hash_move(struct hlist_head *new_info_hash,
}
fib_info_laddrhash = new_laddrhash;
- write_unlock(&fib_info_lock);
+ write_unlock_bh(&fib_info_lock);
bytes = old_size * sizeof(struct hlist_head *);
fib_hash_free(old_info_hash, bytes);
@@ -822,7 +822,7 @@ link_it:
fi->fib_treeref++;
atomic_inc(&fi->fib_clntref);
- write_lock(&fib_info_lock);
+ write_lock_bh(&fib_info_lock);
hlist_add_head(&fi->fib_hash,
&fib_info_hash[fib_info_hashfn(fi)]);
if (fi->fib_prefsrc) {
@@ -841,7 +841,7 @@ link_it:
head = &fib_info_devhash[hash];
hlist_add_head(&nh->nh_hash, head);
} endfor_nexthops(fi)
- write_unlock(&fib_info_lock);
+ write_unlock_bh(&fib_info_lock);
return fi;
err_inval: