CVE-2026-80984
Summary
by MITRE • 09/11/2026
In the Linux kernel, the following vulnerability has been resolved:
net/smc: do not dereference an unset send buffer on the SMC-D teardown path
smc_close_stream_wait() calls smc_tx_prepared_sends() from inside its sk_wait_event() condition, and sk_wait_event() evaluates that condition once with the socket lock released. smcd_buf_detach() clears conn->sndbuf_desc from smc_conn_kill() under lock_sock(), so a link group terminating while a socket waits there leaves the helper dereferencing NULL, faulting out of close(). SIOCOUTQ reads the field by hand, and smc_close_cancel_work() drops the lock across two cancel_*_sync() calls.
Sample the pointer once in the helper, report nothing prepared while it is unset, and bound the ioctl the same way. The receive tasklet dereferences the field directly in smc_cdc_msg_recv_action(), not through this helper; 1/2 is what keeps it from running that late.
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