Re: [PATCH] net/mlx5: fix SRH flex parser initialization synchronization

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,


On 25/12/2025 6:20 PM, Gregory Etelson wrote:
> When multiple threads attempt to create the SRH flex parser
> simultaneously, only the first thread (T[0]) can proceed to the
> initialization code.
> Before doing so, T[0] increases the SRH flex parser reference counter.
> Other threads (T[i]) entering the SRH creation function also increase
> the reference counter before returning a successful code to their
> respective caller functions (CF[i]).
> 
> This can lead to three issues:
> 1. CF[i] may receive a successful return code from the SRH flex parser
> creation function before T[0] completes the parser construction.
> 2. If T[0] fails to create the SRH flex parser, CF[i] will not be
> aware and will assume the parser is valid.
> 3. If T[0] fails, it will not update the SRH flex parser reference
> counter.
> 
> The patch addresses these issues by locking the SRH flex parser node
> creation attempt.
> 
> The first thread to enter the locked section will proceed with the
> node creation.
> If successful, T[0] increases the node reference counter and removes
> the lock.
> If it fails, T[0] removes the lock and returns an error.
> 
> For other threads (T[i]) that obtain the lock, if the flex parser node
> reference count is non-zero, the node has already been created.
> These threads will then increase the reference counter and return
> success.
> Otherwise, they will behave like T[0].
> 
> Fixes: 00e579166cc0 ("net/mlx5: support IPv6 routing extension matching")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Gregory Etelson <getelson@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Patch applied to next-net-mlx,

Kindest regards
Raslan Darawsheh