Re: [PATCH 3/5] svcrdma: Hold a module reference for the backchannel transport

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Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] svcrdma: inaccurate Fixes tag in commit message
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commit 5aa6827a1ec45b94a0a4813a38c3cc653c0334bf
Author: Chuck Lever <cel@kernel.org>

svcrdma: Hold a module reference for the backchannel transport

This commit takes a module reference in xprt_setup_rdma_bc() and releases
it in xprt_rdma_bc_put() so that the rpcrdma module stays pinned while the
backchannel rpc_xprt exists and its deferred destruction work item runs.

>     svcrdma: Hold a module reference for the backchannel transport
>     
>     The last put on an RDMA backchannel rpc_xprt runs xprt_destroy(),
>     which queues xprt_destroy_cb() on a workqueue. That work item calls
>     xprt_rdma_bc_put() through xprt->ops. Nothing pins the rpcrdma
>     module while the rpc_xprt exists: xprt_create_transport() drops the
>     class reference as soon as ->setup() returns, and svc_xprt_free()
>     releases its own module reference right after the final put. An
>     rmmod of rpcrdma can therefore race the pending work item and run
>     freed module text. The TCP backchannel in xs_setup_bc_tcp() and the
>     forward transport in xprt_setup_rdma() both hold a module reference
>     for the life of the rpc_xprt.
>     
>     Take a module reference in xprt_setup_rdma_bc() and release it in
>     xprt_rdma_bc_put(), as xprt_setup_rdma() and xprt_rdma_destroy() do.
>     
>     Fixes: 5d252f90a800 ("svcrdma: Add class for RDMA backwards direction transport")
>     Cc: stable@vger.kernel.org
>     Signed-off-by: Chuck Lever <cel@kernel.org>

[Severity: Low]
In net/sunrpc/xprtrdma/svc_rdma_backchannel.c, commit 5d252f90a800
("svcrdma: Add class for RDMA backwards direction transport") originally
included both try_module_get(THIS_MODULE) in xprt_setup_rdma_bc() and
module_put(THIS_MODULE) in xprt_rdma_bc_put().

Those calls were later removed by commit 07880fa4968b ("svcrdma: Remove
try_module_get from backchannel") when svcrdma and xprtrdma were merged
into a single module.

Should the Fixes tag reference commit 07880fa4968b instead so stable
backporting targets the commit that removed the module reference?

  Fixes: 07880fa4968b ("svcrdma: Remove try_module_get from backchannel")

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