* [PATCH net] net: bridge: annotate data-race in br_fdb_update()
@ 2026-01-06 19:40 Eric Dumazet
2026-01-06 21:26 ` Nikolay Aleksandrov
0 siblings, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2026-01-06 19:40 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, netdev, eric.dumazet, Eric Dumazet,
Nikolay Aleksandrov
fdb->updated is read and written locklessly.
Add READ_ONCE()/WRITE_ONCE() annotations.
Fixes: 31cbc39b6344 ("net: bridge: add option to allow activity notifications for any fdb entries")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
---
net/bridge/br_fdb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 58d22e2b85fc3551bd5aec9c20296ddfcecaa040..e7bd20f0e8d6b7b24aef43d7bed34adf171c34a8 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1002,8 +1002,8 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
unsigned long now = jiffies;
bool fdb_modified = false;
- if (now != fdb->updated) {
- fdb->updated = now;
+ if (now != READ_ONCE(fdb->updated)) {
+ WRITE_ONCE(fdb->updated, now);
fdb_modified = __fdb_mark_active(fdb);
}
--
2.52.0.351.gbe84eed79e-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net] net: bridge: annotate data-race in br_fdb_update()
2026-01-06 19:40 [PATCH net] net: bridge: annotate data-race in br_fdb_update() Eric Dumazet
@ 2026-01-06 21:26 ` Nikolay Aleksandrov
2026-01-07 7:00 ` Nikolay Aleksandrov
0 siblings, 1 reply; 5+ messages in thread
From: Nikolay Aleksandrov @ 2026-01-06 21:26 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, netdev, eric.dumazet
On 06/01/2026 21:40, Eric Dumazet wrote:
> fdb->updated is read and written locklessly.
>
> Add READ_ONCE()/WRITE_ONCE() annotations.
>
> Fixes: 31cbc39b6344 ("net: bridge: add option to allow activity notifications for any fdb entries")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Nikolay Aleksandrov <razor@blackwall.org>
> ---
> net/bridge/br_fdb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> index 58d22e2b85fc3551bd5aec9c20296ddfcecaa040..e7bd20f0e8d6b7b24aef43d7bed34adf171c34a8 100644
> --- a/net/bridge/br_fdb.c
> +++ b/net/bridge/br_fdb.c
> @@ -1002,8 +1002,8 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
> unsigned long now = jiffies;
> bool fdb_modified = false;
>
> - if (now != fdb->updated) {
> - fdb->updated = now;
> + if (now != READ_ONCE(fdb->updated)) {
> + WRITE_ONCE(fdb->updated, now);
> fdb_modified = __fdb_mark_active(fdb);
> }
>
Thanks,
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net: bridge: annotate data-race in br_fdb_update()
2026-01-06 21:26 ` Nikolay Aleksandrov
@ 2026-01-07 7:00 ` Nikolay Aleksandrov
2026-01-07 7:03 ` Nikolay Aleksandrov
0 siblings, 1 reply; 5+ messages in thread
From: Nikolay Aleksandrov @ 2026-01-07 7:00 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, netdev, eric.dumazet
On 06/01/2026 23:26, Nikolay Aleksandrov wrote:
> On 06/01/2026 21:40, Eric Dumazet wrote:
>> fdb->updated is read and written locklessly.
>>
>> Add READ_ONCE()/WRITE_ONCE() annotations.
>>
>> Fixes: 31cbc39b6344 ("net: bridge: add option to allow activity
>> notifications for any fdb entries")
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>> Cc: Nikolay Aleksandrov <razor@blackwall.org>
>> ---
>> net/bridge/br_fdb.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
>> index
>> 58d22e2b85fc3551bd5aec9c20296ddfcecaa040..e7bd20f0e8d6b7b24aef43d7bed34adf171c34a8 100644
>> --- a/net/bridge/br_fdb.c
>> +++ b/net/bridge/br_fdb.c
>> @@ -1002,8 +1002,8 @@ void br_fdb_update(struct net_bridge *br, struct
>> net_bridge_port *source,
>> unsigned long now = jiffies;
>> bool fdb_modified = false;
>> - if (now != fdb->updated) {
>> - fdb->updated = now;
>> + if (now != READ_ONCE(fdb->updated)) {
>> + WRITE_ONCE(fdb->updated, now);
>> fdb_modified = __fdb_mark_active(fdb);
>> }
>
> Thanks,
> Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Actually on second thought, ->updated is used lockless in a few more
places, e.g. br_fdb_fillbuf(), fdb_fill_info(), br_fdb_cleanup().
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net: bridge: annotate data-race in br_fdb_update()
2026-01-07 7:00 ` Nikolay Aleksandrov
@ 2026-01-07 7:03 ` Nikolay Aleksandrov
2026-01-07 8:09 ` Eric Dumazet
0 siblings, 1 reply; 5+ messages in thread
From: Nikolay Aleksandrov @ 2026-01-07 7:03 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, netdev, eric.dumazet
On 07/01/2026 09:00, Nikolay Aleksandrov wrote:
> On 06/01/2026 23:26, Nikolay Aleksandrov wrote:
>> On 06/01/2026 21:40, Eric Dumazet wrote:
>>> fdb->updated is read and written locklessly.
>>>
>>> Add READ_ONCE()/WRITE_ONCE() annotations.
>>>
>>> Fixes: 31cbc39b6344 ("net: bridge: add option to allow activity
>>> notifications for any fdb entries")
>>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>>> Cc: Nikolay Aleksandrov <razor@blackwall.org>
>>> ---
>>> net/bridge/br_fdb.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
>>> index
>>> 58d22e2b85fc3551bd5aec9c20296ddfcecaa040..e7bd20f0e8d6b7b24aef43d7bed34adf171c34a8 100644
>>> --- a/net/bridge/br_fdb.c
>>> +++ b/net/bridge/br_fdb.c
>>> @@ -1002,8 +1002,8 @@ void br_fdb_update(struct net_bridge *br,
>>> struct net_bridge_port *source,
>>> unsigned long now = jiffies;
>>> bool fdb_modified = false;
>>> - if (now != fdb->updated) {
>>> - fdb->updated = now;
>>> + if (now != READ_ONCE(fdb->updated)) {
>>> + WRITE_ONCE(fdb->updated, now);
>>> fdb_modified = __fdb_mark_active(fdb);
>>> }
>>
>> Thanks,
>> Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
>
> Actually on second thought, ->updated is used lockless in a few more
> places, e.g. br_fdb_fillbuf(), fdb_fill_info(), br_fdb_cleanup().
>
I mean I see the subject, but since this patch will get backported
perhaps we can annotate all instances in one go.
Cheers,
Nik
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net: bridge: annotate data-race in br_fdb_update()
2026-01-07 7:03 ` Nikolay Aleksandrov
@ 2026-01-07 8:09 ` Eric Dumazet
0 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2026-01-07 8:09 UTC (permalink / raw)
To: Nikolay Aleksandrov
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
netdev, eric.dumazet
On Wed, Jan 7, 2026 at 8:03 AM Nikolay Aleksandrov <razor@blackwall.org> wrote:
>
> On 07/01/2026 09:00, Nikolay Aleksandrov wrote:
> > On 06/01/2026 23:26, Nikolay Aleksandrov wrote:
> >> On 06/01/2026 21:40, Eric Dumazet wrote:
> >>> fdb->updated is read and written locklessly.
> >>>
> >>> Add READ_ONCE()/WRITE_ONCE() annotations.
> >>>
> >>> Fixes: 31cbc39b6344 ("net: bridge: add option to allow activity
> >>> notifications for any fdb entries")
> >>> Signed-off-by: Eric Dumazet <edumazet@google.com>
> >>> Cc: Nikolay Aleksandrov <razor@blackwall.org>
> >>> ---
> >>> net/bridge/br_fdb.c | 4 ++--
> >>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> >>> index
> >>> 58d22e2b85fc3551bd5aec9c20296ddfcecaa040..e7bd20f0e8d6b7b24aef43d7bed34adf171c34a8 100644
> >>> --- a/net/bridge/br_fdb.c
> >>> +++ b/net/bridge/br_fdb.c
> >>> @@ -1002,8 +1002,8 @@ void br_fdb_update(struct net_bridge *br,
> >>> struct net_bridge_port *source,
> >>> unsigned long now = jiffies;
> >>> bool fdb_modified = false;
> >>> - if (now != fdb->updated) {
> >>> - fdb->updated = now;
> >>> + if (now != READ_ONCE(fdb->updated)) {
> >>> + WRITE_ONCE(fdb->updated, now);
> >>> fdb_modified = __fdb_mark_active(fdb);
> >>> }
> >>
> >> Thanks,
> >> Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
> >
> > Actually on second thought, ->updated is used lockless in a few more
> > places, e.g. br_fdb_fillbuf(), fdb_fill_info(), br_fdb_cleanup().
> >
>
> I mean I see the subject, but since this patch will get backported
> perhaps we can annotate all instances in one go.
Sure, I will send a V2, thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-01-06 19:40 [PATCH net] net: bridge: annotate data-race in br_fdb_update() Eric Dumazet
2026-01-06 21:26 ` Nikolay Aleksandrov
2026-01-07 7:00 ` Nikolay Aleksandrov
2026-01-07 7:03 ` Nikolay Aleksandrov
2026-01-07 8:09 ` Eric Dumazet
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