Re: [PATCH net] net/sched: flower: Fix wrong handle assignment during filter change

[Simon Horman]

On Tue, Apr 25, 2023 at 04:06:04PM +0200, Ivan Vecera wrote:
> Commit 08a0063df3ae ("net/sched: flower: Move filter handle initialization
> earlier") moved filter handle initialization but an assignment of
> the handle to fnew->handle is done regardless of fold value. This is wrong
> because if fold != NULL (so fold->handle == handle) no new handle is
> allocated and passed handle is assigned to fnew->handle. Then if any
> subsequent action in fl_change() fails then the handle value is
> removed from IDR that is incorrect as we will have still valid old filter
> instance with handle that is not present in IDR.
> Fix this issue by moving the assignment so it is done only when passed
> fold == NULL.
> 
> Prior the patch:
> [root@machine tc-testing]# ./tdc.py -d enp1s0f0np0 -e 14be
> Test 14be: Concurrently replace same range of 100k flower filters from 10 tc instances
> exit: 123
> exit: 0
> RTNETLINK answers: Invalid argument
> We have an error talking to the kernel
> Command failed tmp/replace_6:1885
> 
> 
> All test results:
> 
> 1..1
> not ok 1 14be - Concurrently replace same range of 100k flower filters from 10 tc instances
>         Command exited with 123, expected 0
> RTNETLINK answers: Invalid argument
> We have an error talking to the kernel
> Command failed tmp/replace_6:1885
> 
> After the patch:
> [root@machine tc-testing]# ./tdc.py -d enp1s0f0np0 -e 14be
> Test 14be: Concurrently replace same range of 100k flower filters from 10 tc instances
> 
> All test results:
> 
> 1..1
> ok 1 14be - Concurrently replace same range of 100k flower filters from 10 tc instances
> 
> Fixes: 08a0063df3ae ("net/sched: flower: Move filter handle initialization earlier")
> Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>

Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>