* [PATCH bpf] bpf: sockmap: add locking annotations to iterator
@ 2020-10-12 9:18 Lorenz Bauer
2020-10-12 18:10 ` John Fastabend
2020-10-14 8:46 ` Jakub Sitnicki
0 siblings, 2 replies; 3+ messages in thread
From: Lorenz Bauer @ 2020-10-12 9:18 UTC (permalink / raw)
To: John Fastabend, Daniel Borkmann, Jakub Sitnicki, Lorenz Bauer,
David S. Miller, Jakub Kicinski, Alexei Starovoitov,
Yonghong Song
Cc: kernel-team, kernel test robot, netdev, bpf, linux-kernel
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(+)
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);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH bpf] bpf: sockmap: add locking annotations to iterator
2020-10-12 9:18 [PATCH bpf] bpf: sockmap: add locking annotations to iterator Lorenz Bauer
@ 2020-10-12 18:10 ` John Fastabend
2020-10-14 8:46 ` Jakub Sitnicki
1 sibling, 0 replies; 3+ messages in thread
From: John Fastabend @ 2020-10-12 18:10 UTC (permalink / raw)
To: Lorenz Bauer, John Fastabend, Daniel Borkmann, Jakub Sitnicki,
Lorenz Bauer, David S. Miller, Jakub Kicinski,
Alexei Starovoitov, Yonghong Song
Cc: kernel-team, kernel test robot, netdev, bpf, linux-kernel
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf] bpf: sockmap: add locking annotations to iterator
2020-10-12 9:18 [PATCH bpf] bpf: sockmap: add locking annotations to iterator Lorenz Bauer
2020-10-12 18:10 ` John Fastabend
@ 2020-10-14 8:46 ` Jakub Sitnicki
1 sibling, 0 replies; 3+ messages in thread
From: Jakub Sitnicki @ 2020-10-14 8:46 UTC (permalink / raw)
To: Lorenz Bauer
Cc: John Fastabend, Daniel Borkmann, David S. Miller, Jakub Kicinski,
Alexei Starovoitov, Yonghong Song, kernel-team,
kernel test robot, netdev, bpf, linux-kernel
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-10-12 18:10 ` John Fastabend
2020-10-14 8:46 ` Jakub Sitnicki
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