From: Chengfeng Ye <nicoyip.dev@gmail.com> stable inclusion from stable-v6.6.153 commit 577443530cb592d5782a1f79847411a9363a65c8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/17690 CVE: CVE-2026-74479 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 817ff6efdb7f484ea547218e11e17d8e43daa3b4 ] pktgen_change_name() replaces pkt_dev->entry while holding t->if_lock. pktgen_remove_device() removes the same entry before _rem_dev_from_if_list() takes that lock. This allows the following interleaving: CPU 0 (NETDEV_CHANGENAME) CPU 1 (kpktgend) if_lock(t) proc_remove(pkt_dev->entry) proc_remove(pkt_dev->entry) pkt_dev->entry = proc_create_data(...) if_unlock(t) The kthread can pass the stale proc_dir_entry to proc_remove() after the rename path has freed it. A reproducer with a widened race window reports: BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80 Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67 Call Trace: proc_remove+0x78/0x80 pktgen_remove_device.isra.0+0x11c/0x4c0 pktgen_thread_worker+0x1214/0x6bc0 kthread+0x2c6/0x3b0 Allocated by task 95: __proc_create+0x204/0x790 proc_create_data+0x72/0xe0 pktgen_thread_write+0xd61/0x1510 Freed by task 28: kmem_cache_free+0xcb/0x3d0 proc_free_inode+0x5b/0x80 rcu_core+0x50a/0x1850 The buggy address belongs to the object at ffff8881478fea00 which belongs to the cache proc_dir_entry of size 192 Move proc_remove() into the if_lock-protected list removal helper. Keep it before list_del_rcu() to preserve the ordering required by add_device(). The rename path must then finish replacing the entry before removal, or it observes that the device is no longer on the list. Fixes: 39df232f1a9b ("[PKTGEN]: fix device name handling") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye <nicoyip.dev@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20260719145740.2888967-1-nicoyip.dev@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: net/core/pktgen.c [577443530cb5 moves proc_remove() into the if_lock-protected _rem_dev_from_if_list() helper to close a proc entry use-after-free race between pktgen_change_name() and pktgen_remove_device(). In the downstream tree the comment above pktgen_remove_device()'s proc_remove() call still used the single-line '*/' closing style, so the hunk was adjusted to drop the now-redundant proc_remove(pkt_dev->entry) call and the 'And update the thread if_list' comment, while keeping the proc_remove() addition inside _rem_dev_from_if_list() intact. Semantically equivalent to the upstream fix.] Signed-off-by: JiangJieHua <jiangjiehua1@huawei.com> --- net/core/pktgen.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 32a60c8195d5f..83efb7be323eb 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3881,6 +3881,7 @@ static void _rem_dev_from_if_list(struct pktgen_thread *t, struct pktgen_dev *p; if_lock(t); + proc_remove(pkt_dev->entry); list_for_each_safe(q, n, &t->if_list) { p = list_entry(q, struct pktgen_dev, list); if (p == pkt_dev) @@ -3909,9 +3910,6 @@ static int pktgen_remove_device(struct pktgen_thread *t, /* Remove proc before if_list entry, because add_device uses * list to determine if interface already exist, avoid race * with proc_create_data() */ - proc_remove(pkt_dev->entry); - - /* And update the thread if_list */ _rem_dev_from_if_list(t, pkt_dev); #ifdef CONFIG_XFRM -- 2.33.8