net/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80981
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:04 UTC
Updated2026-09-11 20:19:04 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/smc: fix use-after-free of the LLC qentry in smc_llc_srv_add_link() smc_llc_srv_add_link() keeps add_llc pointing into the queue entry: add_llc = &qentry->msg.add_link; smc_llc.c:1482 ... smc_llc_save_add_link_info(link_new, add_llc); smc_llc.c:1494 smc_llc_flow_qentry_del(&lgr->llc_flow_lcl); smc_llc.c:1495 ... u8 *llc_msg = smc_link_shared_v2_rxbuf(link) ? (u8 *)lgr->wr_rx_buf_v2 : (u8 *)add_llc; smc_llc.c:1504 smc_llc_save_add_link_rkeys(link, link_new, llc_msg); smc_llc.c:1506 smc_llc_flow_qentry_del() kfree()s the entry, so on a link without a shared v2 receive buffer the pointer handed to smc_llc_save_add_link_rkeys() is already freed. Before the Fixes: commit that branch always used lgr->wr_rx_buf_v2 and add_llc was not used after the free. Reproduced on an unpatched tree over rxe, with KASAN, kasan_multi_shot and a link forced to max_recv_sge == 1: the entry is freed and read by the same call, and the freeing frame is smc_llc_srv_add_link() itself. [ 2.523161] BUG: KASAN: slab-use-after-free in smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.523499] Read of size 2 at addr ffff8880052194de by task kworker/0:1/11 [ 2.523789] [ 2.523862] CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 7.2.0-rc5-p0-g2c9dd296545d #35 PREEMPT(lazy) [ 2.523865] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 2.523866] Workqueue: smc_hs_wq smc_listen_work [ 2.523869] Call Trace: [ 2.523870] <TASK> [ 2.523871] dump_stack_lvl+0x53/0x70 [ 2.523872] print_report+0xd0/0x630 [ 2.523874] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 2.523876] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.523878] kasan_report+0xce/0x100 [ 2.523879] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.523881] smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.523883] ? smcr_buf_reg_lgr+0x2a4/0x660 [ 2.523885] smc_llc_srv_add_link+0xaa2/0x1e50 [ 2.523888] ? _printk+0xba/0xf0 [ 2.523897] ? __pfx_smc_llc_srv_add_link+0x10/0x10 [ 2.523899] ? down_write+0xb0/0x130 [ 2.523903] ? __pfx_down_write+0x10/0x10 [ 2.523905] smc_listen_work+0x489e/0x4d00 [ 2.523907] ? kmem_cache_free+0x1c6/0x3a0 [ 2.523911] ? __pfx_smc_listen_work+0x10/0x10 [ 2.523913] ? release_sock+0x148/0x1d0 [ 2.523915] ? smc_tcp_listen_work+0xb4f/0xfc0 [ 2.523917] ? _raw_spin_lock_irq+0x80/0xe0 [ 2.523918] ? __pfx__raw_spin_lock_irq+0x10/0x10 [ 2.523920] process_one_work+0x633/0x1030 [ 2.523922] ? assign_work+0x11d/0x370 [ 2.523924] worker_thread+0x45b/0xd10 [ 2.523926] ? __pfx_worker_thread+0x10/0x10 [ 2.523928] ? __pfx_worker_thread+0x10/0x10 [ 2.523929] kthread+0x2c6/0x3b0 [ 2.523931] ? recalc_sigpending+0x15c/0x1e0 [ 2.523934] ? __pfx_kthread+0x10/0x10 [ 2.523935] ret_from_fork+0x36e/0x5a0 [ 2.523937] ? __pfx_ret_from_fork+0x10/0x10 [ 2.523938] ? __switch_to+0x572/0xdd0 [ 2.523943] ? __pfx_kthread+0x10/0x10 [ 2.523944] ret_from_fork_asm+0x1a/0x30 [ 2.523947] </TASK> [ 2.523948] [ 2.531253] Allocated by task 48: [ 2.531399] kasan_save_stack+0x33/0x60 [ 2.531570] kasan_save_track+0x14/0x30 [ 2.531737] __kasan_kmalloc+0x8f/0xa0 [ 2.531905] __kmalloc_cache_noprof+0x158/0x370 [ 2.532100] smc_llc_enqueue+0x72/0x560 [ 2.532268] smc_wr_rx_tasklet_fn+0x474/0xa80 [ 2.532491] tasklet_action_common+0x20f/0x8a0 [ 2.532714] handle_softirqs+0x18e/0x590 [ 2.532886] do_softirq+0x3b/0x60 [ 2.533036] __local_bh_enable_ip+0x61/0x70 [ 2.533221] __alloc_skb+0x732/0x890 [ 2.533384] rxe_init_packet+0x16b/0x4f0 [ 2.533567] prepare_ack_packet+0xb8/0x830 [ 2.533760] rxe_receiver+0x495/0x96e0 [ 2.533933] do_work+0x144/0x470 [ 2 ---truncated---

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 27ef6a9981fe74191849966a6d5e0400a4008ab8 c52a998a223e7e84333306996edec096178d1e95 git Not specified
CNA Linux Linux affected 27ef6a9981fe74191849966a6d5e0400a4008ab8 adef84cc85d449ac28d2b4b4c49cf19619c56e27 git Not specified
CNA Linux Linux affected 27ef6a9981fe74191849966a6d5e0400a4008ab8 a42a459ef0e54cb0c4b3e43e21cb0e658e664f64 git Not specified
CNA Linux Linux affected 6.14 Not specified
CNA Linux Linux unaffected 6.14 semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/a42a459ef0e54cb0c4b3e43e21cb0e658e664f64 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/adef84cc85d449ac28d2b4b4c49cf19619c56e27 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c52a998a223e7e84333306996edec096178d1e95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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