| Message ID | 20201012091850.67452-1-lmb@cloudflare.com |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf] bpf: sockmap: add locking annotations to iterator | expand |
Lorenz Bauer wrote: > The sparse checker currently outputs the following warnings: > > include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_hash_seq_start' - wrong count at exit > include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_map_seq_start' - wrong count at exit > > Add the necessary __acquires and __release annotations to make the > iterator locking schema palatable to sparse. Also add __must_hold > for good measure. > > The kernel codebase uses both __acquires(rcu) and __acquires(RCU). > I couldn't find any guidance which one is preferred, so I used > what is easier to type out. > > Fixes: 0365351524d7 ("net: Allow iterating sockmap and sockhash") > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> > --- LGTM Acked-by: John Fastabend <john.fastabend@gmail.com>
On Mon, Oct 12, 2020 at 11:18 AM CEST, Lorenz Bauer wrote: > The sparse checker currently outputs the following warnings: > > include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_hash_seq_start' - wrong count at exit > include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_map_seq_start' - wrong count at exit > > Add the necessary __acquires and __release annotations to make the > iterator locking schema palatable to sparse. Also add __must_hold > for good measure. > > The kernel codebase uses both __acquires(rcu) and __acquires(RCU). > I couldn't find any guidance which one is preferred, so I used > what is easier to type out. > > Fixes: 0365351524d7 ("net: Allow iterating sockmap and sockhash") > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> > --- Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index df09c39a4dd2..203900a6ca5f 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -745,6 +745,7 @@ static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info) } static void *sock_map_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(rcu) { struct sock_map_seq_info *info = seq->private; @@ -757,6 +758,7 @@ static void *sock_map_seq_start(struct seq_file *seq, loff_t *pos) } static void *sock_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) + __must_hold(rcu) { struct sock_map_seq_info *info = seq->private; @@ -767,6 +769,7 @@ static void *sock_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) } static int sock_map_seq_show(struct seq_file *seq, void *v) + __must_hold(rcu) { struct sock_map_seq_info *info = seq->private; struct bpf_iter__sockmap ctx = {}; @@ -789,6 +792,7 @@ static int sock_map_seq_show(struct seq_file *seq, void *v) } static void sock_map_seq_stop(struct seq_file *seq, void *v) + __releases(rcu) { if (!v) (void)sock_map_seq_show(seq, NULL); @@ -1353,6 +1357,7 @@ static void *sock_hash_seq_find_next(struct sock_hash_seq_info *info, } static void *sock_hash_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(rcu) { struct sock_hash_seq_info *info = seq->private; @@ -1365,6 +1370,7 @@ static void *sock_hash_seq_start(struct seq_file *seq, loff_t *pos) } static void *sock_hash_seq_next(struct seq_file *seq, void *v, loff_t *pos) + __must_hold(rcu) { struct sock_hash_seq_info *info = seq->private; @@ -1373,6 +1379,7 @@ static void *sock_hash_seq_next(struct seq_file *seq, void *v, loff_t *pos) } static int sock_hash_seq_show(struct seq_file *seq, void *v) + __must_hold(rcu) { struct sock_hash_seq_info *info = seq->private; struct bpf_iter__sockmap ctx = {}; @@ -1396,6 +1403,7 @@ static int sock_hash_seq_show(struct seq_file *seq, void *v) } static void sock_hash_seq_stop(struct seq_file *seq, void *v) + __releases(rcu) { if (!v) (void)sock_hash_seq_show(seq, NULL);
The sparse checker currently outputs the following warnings: include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_hash_seq_start' - wrong count at exit include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_map_seq_start' - wrong count at exit Add the necessary __acquires and __release annotations to make the iterator locking schema palatable to sparse. Also add __must_hold for good measure. The kernel codebase uses both __acquires(rcu) and __acquires(RCU). I couldn't find any guidance which one is preferred, so I used what is easier to type out. Fixes: 0365351524d7 ("net: Allow iterating sockmap and sockhash") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> --- net/core/sock_map.c | 8 ++++++++ 1 file changed, 8 insertions(+)