Messages in this thread Patch in this message | | | Date | Mon, 21 Aug 2006 11:47:38 -0700 | From | Greg KH <> | Subject | [patch 16/20] Fix ipv4 routing locking bug |
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-stable review patch. If anyone has any objections, please let us know.
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From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
[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: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- net/ipv4/fib_semantics.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- linux-2.6.17.9.orig/net/ipv4/fib_semantics.c +++ linux-2.6.17.9/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 *f 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_h 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_h } 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: -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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