From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f199.google.com (mail-il1-f199.google.com [209.85.166.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C03AE1DE3B7 for ; Tue, 7 Oct 2025 05:24:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759814642; cv=none; b=oA1h5ivU2EP1scLxzIe78KstIAYM16o8qBoCsw7enk14CLCcgkHMTxqYvFbuM57Cf/PROmQQBZUEqA1cadoo7VbT0G89MLk9MTYLDNYzo5AZ2GRRLLjWM+sVkDamNHwPfGnC/J9YwAXtI9wHQ27mUq+vxXJfTTlIq3p34hdXrOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759814642; c=relaxed/simple; bh=h8TuDIukrI++VVhyoE0GCZIIYNv6d0W/E5vDju3p1wQ=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To:Cc: Content-Type; 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List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:b26:b0:424:9926:a97b with SMTP id e9e14a558f8ab-42e7ada9885mr203720245ab.25.1759814639922; Mon, 06 Oct 2025 22:23:59 -0700 (PDT) Date: Mon, 06 Oct 2025 22:23:59 -0700 In-Reply-To: <20251006193103.2684156-1-edumazet@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68e4a3ef.a00a0220.298cc0.0472.GAE@google.com> Subject: [syzbot ci] Re: net: optimize TX throughput and efficiency From: syzbot ci To: davem@davemloft.net, edumazet@google.com, eric.dumazet@gmail.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, kuniyu@google.com, netdev@vger.kernel.org, pabeni@redhat.com, willemb@google.com, xiyou.wangcong@gmail.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v1] net: optimize TX throughput and efficiency https://lore.kernel.org/all/20251006193103.2684156-1-edumazet@google.com * [PATCH RFC net-next 1/5] net: add add indirect call wrapper in skb_release_head_state() * [PATCH RFC net-next 2/5] net/sched: act_mirred: add loop detection * [PATCH RFC net-next 3/5] Revert "net/sched: Fix mirred deadlock on device recursion" * [PATCH RFC net-next 4/5] net: sched: claim one cache line in Qdisc * [PATCH RFC net-next 5/5] net: dev_queue_xmit() llist adoption and found the following issue: KASAN: slab-use-after-free Read in netem_dequeue Full report is available here: https://ci.syzbot.org/series/e8660f67-35a0-406e-96ee-a401d3f30ff9 *** KASAN: slab-use-after-free Read in netem_dequeue tree: net-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net-next.git base: f1455695d2d99894b65db233877acac9a0e120b9 arch: amd64 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 config: https://ci.syzbot.org/builds/2db7ec92-610b-4887-bf33-d0b4c04760c8/config syz repro: https://ci.syzbot.org/findings/3ca47f46-1b94-48b6-bab9-5996b7162c30/syz_repro ================================================================== BUG: KASAN: slab-use-after-free in netem_dequeue+0x4e7/0x1430 net/sched/sch_netem.c:720 Read of size 8 at addr ffff888020b65b30 by task ksoftirqd/1/23 CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 netem_dequeue+0x4e7/0x1430 net/sched/sch_netem.c:720 dequeue_skb net/sched/sch_generic.c:294 [inline] qdisc_restart net/sched/sch_generic.c:399 [inline] __qdisc_run+0x23c/0x15f0 net/sched/sch_generic.c:417 qdisc_run+0xc5/0x290 include/net/pkt_sched.h:126 net_tx_action+0x7c9/0x980 net/core/dev.c:5731 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5913: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4292 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x13c/0xc40 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_cr net/ipv6/mcast.c:2148 [inline] mld_ifc_work+0x6ed/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 23: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4797 br_dev_xmit+0x11b3/0x1840 net/bridge/br_device.c:108 __netdev_start_xmit include/linux/netdevice.h:5248 [inline] netdev_start_xmit include/linux/netdevice.h:5257 [inline] xmit_one net/core/dev.c:3845 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3861 sch_direct_xmit+0x241/0x4b0 net/sched/sch_generic.c:344 qdisc_restart net/sched/sch_generic.c:409 [inline] __qdisc_run+0xb16/0x15f0 net/sched/sch_generic.c:417 qdisc_run+0xc5/0x290 include/net/pkt_sched.h:126 net_tx_action+0x7c9/0x980 net/core/dev.c:5731 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888020b65b00 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 48 bytes inside of freed 240-byte region [ffff888020b65b00, ffff888020b65bf0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20b64 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801cedf8c0 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000150015 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801cedf8c0 dead000000000122 0000000000000000 head: 0000000000000000 0000000000150015 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea000082d901 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x72820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_MEMALLOC|__GFP_COMP), pid 0, tgid 0 (swapper/0), ts 96149950019, free_ts 42914869228 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2660 new_slab mm/slub.c:2714 [inline] ___slab_alloc+0xbeb/0x1420 mm/slub.c:3901 __slab_alloc mm/slub.c:3992 [inline] __slab_alloc_node mm/slub.c:4067 [inline] slab_alloc_node mm/slub.c:4228 [inline] kmem_cache_alloc_node_noprof+0x280/0x3c0 mm/slub.c:4292 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660 __netdev_alloc_skb+0x108/0x970 net/core/skbuff.c:734 netdev_alloc_skb include/linux/skbuff.h:3484 [inline] dev_alloc_skb include/linux/skbuff.h:3497 [inline] __ieee80211_beacon_get+0xc06/0x1880 net/mac80211/tx.c:5652 ieee80211_beacon_get_tim+0xb4/0x2b0 net/mac80211/tx.c:5774 ieee80211_beacon_get include/net/mac80211.h:5667 [inline] mac80211_hwsim_beacon_tx+0x3ce/0x860 drivers/net/wireless/virtual/mac80211_hwsim.c:2355 __iterate_interfaces+0x2ab/0x590 net/mac80211/util.c:761 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:797 mac80211_hwsim_beacon+0xbb/0x1c0 drivers/net/wireless/virtual/mac80211_hwsim.c:2389 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 page last free pid 0 tgid 0 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Memory state around the buggy address: ffff888020b65a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff888020b65a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888020b65b00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888020b65b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff888020b65c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com.