* [PATCH] sfc: extend the locking on mcdi->seqno
@ 2022-03-01 22:28 Niels Dossche
2022-03-03 8:12 ` Martin Habets
2022-03-03 14:20 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Niels Dossche @ 2022-03-01 22:28 UTC (permalink / raw)
To: netdev
Cc: Edward Cree, Martin Habets, David S. Miller, Jakub Kicinski,
Niels Dossche
seqno could be read as a stale value outside of the lock. The lock is
already acquired to protect the modification of seqno against a possible
race condition. Place the reading of this value also inside this locking
to protect it against a possible race condition.
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
---
drivers/net/ethernet/sfc/mcdi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index be6bfd6b7ec7..50baf62b2cbc 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -163,9 +163,9 @@ static void efx_mcdi_send_request(struct efx_nic *efx, unsigned cmd,
/* Serialise with efx_mcdi_ev_cpl() and efx_mcdi_ev_death() */
spin_lock_bh(&mcdi->iface_lock);
++mcdi->seqno;
+ seqno = mcdi->seqno & SEQ_MASK;
spin_unlock_bh(&mcdi->iface_lock);
- seqno = mcdi->seqno & SEQ_MASK;
xflags = 0;
if (mcdi->mode == MCDI_MODE_EVENTS)
xflags |= MCDI_HEADER_XFLAGS_EVREQ;
--
2.35.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] sfc: extend the locking on mcdi->seqno
2022-03-01 22:28 [PATCH] sfc: extend the locking on mcdi->seqno Niels Dossche
@ 2022-03-03 8:12 ` Martin Habets
2022-03-03 14:20 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Martin Habets @ 2022-03-03 8:12 UTC (permalink / raw)
To: Niels Dossche; +Cc: netdev, Edward Cree, David S. Miller, Jakub Kicinski
On Tue, Mar 01, 2022 at 11:28:22PM +0100, Niels Dossche wrote:
> seqno could be read as a stale value outside of the lock. The lock is
> already acquired to protect the modification of seqno against a possible
> race condition. Place the reading of this value also inside this locking
> to protect it against a possible race condition.
>
> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Acked-by: Martin Habets <habetsm.xilinx@gmail.com>
> ---
> drivers/net/ethernet/sfc/mcdi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
> index be6bfd6b7ec7..50baf62b2cbc 100644
> --- a/drivers/net/ethernet/sfc/mcdi.c
> +++ b/drivers/net/ethernet/sfc/mcdi.c
> @@ -163,9 +163,9 @@ static void efx_mcdi_send_request(struct efx_nic *efx, unsigned cmd,
> /* Serialise with efx_mcdi_ev_cpl() and efx_mcdi_ev_death() */
> spin_lock_bh(&mcdi->iface_lock);
> ++mcdi->seqno;
> + seqno = mcdi->seqno & SEQ_MASK;
> spin_unlock_bh(&mcdi->iface_lock);
>
> - seqno = mcdi->seqno & SEQ_MASK;
> xflags = 0;
> if (mcdi->mode == MCDI_MODE_EVENTS)
> xflags |= MCDI_HEADER_XFLAGS_EVREQ;
> --
> 2.35.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] sfc: extend the locking on mcdi->seqno
2022-03-01 22:28 [PATCH] sfc: extend the locking on mcdi->seqno Niels Dossche
2022-03-03 8:12 ` Martin Habets
@ 2022-03-03 14:20 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-03-03 14:20 UTC (permalink / raw)
To: Niels Dossche; +Cc: netdev, ecree.xilinx, habetsm.xilinx, davem, kuba
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:
On Tue, 1 Mar 2022 23:28:22 +0100 you wrote:
> seqno could be read as a stale value outside of the lock. The lock is
> already acquired to protect the modification of seqno against a possible
> race condition. Place the reading of this value also inside this locking
> to protect it against a possible race condition.
>
> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
>
> [...]
Here is the summary with links:
- sfc: extend the locking on mcdi->seqno
https://git.kernel.org/netdev/net/c/f1fb205efb0c
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-01 22:28 [PATCH] sfc: extend the locking on mcdi->seqno Niels Dossche
2022-03-03 8:12 ` Martin Habets
2022-03-03 14:20 ` patchwork-bot+netdevbpf
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