net/smc: unregister the connection before draining the rx tasklet

Summary

In the Linux kernel, the following vulnerability has been resolved: net/smc: unregister the connection before draining the rx tasklet smc_conn_free() calls smc_ism_unset_conn() only while the link group is still on its device list, and never sets conn->killed. smc_lgr_terminate_sched() unlinks the group immediately and defers killing its connections to a work item, so a connection freed in that window keeps its smcd->conn[] slot with both gates in smcd_handle_irq() open, and the device can re-arm the receive tasklet after tasklet_kill() has returned. On the DMB-nocopy path the ghost send buffer is freed right after that drain, so the re-armed tasklet dereferences it. Unregister unconditionally and drain before the detach at both teardown sites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain. Clear conn->sndbuf_desc before freeing it as well, so a reader that samples the pointer cannot get one that is already freed.

Timeline

1. Sep 11, 2026, 7:42 PM UTCCVE published
2. Oct 19, 2026, 8:46 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 21f6f41e82e59740e26e06e77bdf58dc7f6f08dd · fixed in b6b6ac713ee82b340a8e3be30b101bd2840deec4; From ae2be35cbed2c8385e890147ea321a3fcc3ca5fa · fixed in b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5; From ae2be35cbed2c8385e890147ea321a3fcc3ca5fa · fixed in 5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3; From ae2be35cbed2c8385e890147ea321a3fcc3ca5fa · fixed in b74d313567dfc1b7e56629ddbad04e728686f235; From ae2be35cbed2c8385e890147ea321a3fcc3ca5fa · fixed in 36cdf5d48ca191dcd71c28cadbe0981b1d25318d; From 6.6.66 · fixed in 6.6.157

• Linux Linux

  6.10

• KernelLinux

  fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.10.0 · fixed in 6.18.50; From 6.13.0 · fixed in 7.2.4

References 5