In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler()

The SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT branch in
smc_llc_event_handler() stores an incoming qentry into the local LLC flow
without first checking whether a qentry is already pending. If a malicious or
buggy peer sends a second CONFIRM_LINK or ADD_LINK_CONT request while a flow is
active and flow->qentry is already set, smc_llc_flow_qentry_set() overwrites the
pointer without freeing the previous allocation, leaking one kmalloc-96 object
per spurious message.

The sibling SMC_LLC_DELETE_LINK branch already has the correct !flow->qentry
guard. Apply the same guard to the CONFIRM_LINK/ADD_LINK_CONT branch so that a
duplicate message when qentry is already occupied falls through to break and is
freed by the kfree(qentry) at the out: label, rather than silently leaking the
existing allocation.

The response direction (smc_llc_rx_response()) is unaffected: it already guards
with flow->qentry at the equivalent site and drops duplicate responses
correctly.

https://git.kernel.org/stable/c/06734dfeaeba886aab1bf147249195b888ac3e4d

https://git.kernel.org/stable/c/10cb31b2b74cb664c6c95cf72364d7d5c483ab82

https://git.kernel.org/stable/c/976245094925bab9bc39366b2e9ab44ffcde61d0

https://git.kernel.org/stable/c/a1e980d7a9e7ee6faf4f5fd7b450413b969af26d

https://git.kernel.org/stable/c/bfc336a9fbbf09805f3dfe25c195a4db90af2846

https://git.kernel.org/stable/c/c23c409228629107203d3c3e95fff1473173f1a6

https://git.kernel.org/stable/c/e0eb87677c76b157cdf8eb7c1f19e56227165a33

https://git.kernel.org/stable/c/e384f3cba6ea709f5b2272b1770db4ce14047f78

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