Re: [PATCH v1 4/5] svcrdma: release a send context stranded by a partial post

[sashiko-bot@kernel.org]

> When ib_post_send() rejects a WR mid-chain, svc_rdma_post_send_err()
> returns zero to say that a completion will clean up. The Write and
> Reply chunk WRs in a reply's chain do carry completions, but those
> only trace or close the transport. The Send at the chain's tail is
> the one whose completion puts the send context, so a chain cut
> before the Send leaves the context unreleased. svc_rdma_sendto()
> reports success and never puts it either. No list the transport
> destructor walks holds the context, so it leaks past teardown along
> with the DMA mappings, page references, and rw contexts it owns.
> 
> The error path cannot release the context itself. The posted WRs
> still reference its rw contexts and pages, and the HCA may still be
> reading them. Nor can it drain the Send Queue to wait for them. A
> drain needs a free SQ slot for its marker WR. A provider that
> rejects a WR after accepting earlier ones has most likely diverged
> [ ... ]
> contract. The chain became long enough to cut only with commit
> 10e6fc1054d9 ("svcrdma: Post the Reply chunk and Send WR together").
> 
> Fixes: 71b43531ee0b ("svcrdma: Post Send WR chain")
> Signed-off-by: Chuck Lever <cel@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260922015128.240977-1-cel@kernel.org?part=4