Re: [PATCH] net/smc: replace strncpy with strscpy for ib_name
From: Leon Romanovsky <leon@kernel.org>
Date: 2025-09-15 08:02:39
Also in:
linux-kernel-mentees, linux-rdma, linux-s390, lkml
From: Leon Romanovsky <leon@kernel.org>
Date: 2025-09-15 08:02:39
Also in:
linux-kernel-mentees, linux-rdma, linux-s390, lkml
On Mon, Sep 15, 2025 at 12:24:16PM +0530, Mahanta Jambigi wrote:
On 12/09/25 2:37 pm, Leon Romanovsky wrote:quoted
On Fri, Sep 12, 2025 at 01:18:52PM +0530, Mahanta Jambigi wrote:quoted
On 10/09/25 3:31 pm, Leon Romanovsky wrote:quoted
quoted
--- a/net/smc/smc_pnet.c +++ b/net/smc/smc_pnet.c@@ -450,7 +450,7 @@ static int smc_pnet_add_ib(struct smc_pnettable *pnettable, char *ib_name, return -ENOMEM; new_pe->type = SMC_PNET_IB; memcpy(new_pe->pnet_name, pnet_name, SMC_MAX_PNETID_LEN); - strncpy(new_pe->ib_name, ib_name, IB_DEVICE_NAME_MAX); + strscpy(new_pe->ib_name, ib_name);It is worth to mention that caching ib_name is wrong as IB/core provides IB device rename functionality.In our case we hit this code path where we pass *PCI_ID* as the *ib_name* using *smc_pnet* tool(smc_pnet -a <pnet_name> -D <PCI_ID>). I believe PCI_ID will not change, so caching it here is fine.If I remember, you are reporting that cached ib_name through netlink much later. The caching itself is not an issue, but incorrect reported name can be seen as a wrong thing to do.In what case we can see this incorrect reported name, could you please elaborate.
Did you open net/smc/smc_pnet.c? Everything that uses ib_name in that file is incorrect. From glance look: 1. smc_pnet_find_ib() returns completely random results if device is renamed in parallel. 2. SMC_PNETID_GET returns wrong names. It returns cached name which doesn't exist anymore. IB devices have stable indexes in similar way to netdevice. The code should rely on it and not on the name. Thanks