{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-35892",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2024-35892"
  ],
  "published": "2024-05-19T08:35:32Z",
  "summary": "net/sched: fix lockdep splat in qdisc_tree_reduce_backlog()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix lockdep splat in qdisc_tree_reduce_backlog()\n\nqdisc_tree_reduce_backlog() is called with the qdisc lock held,\nnot RTNL.\n\nWe must use qdisc_lookup_rcu() instead of qdisc_lookup()\n\nsyzbot reported:\n\nWARNING: suspicious RCU usage\n6.1.74-syzkaller #0 Not tainted\n-----------------------------\nnet/sched/sch_api.c:305 suspicious rcu_dereference_protected() usage!\n\nother info that might help us debug this:\n\nrcu_scheduler_active = 2, debug_locks = 1\n3 locks held by udevd/1142:\n  #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]\n  #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]\n  #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: net_tx_action+0x64a/0x970 net/core/dev.c:5282\n  #1: ffff888171861108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]\n  #1: ffff888171861108 (&sch->q.lock){+.-.}-{2:2}, at: net_tx_action+0x754/0x970 net/core/dev.c:5297\n  #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]\n  #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]\n  #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: qdisc_tree_reduce_backlog+0x84/0x580 net/sched/sch_api.c:792\n\nstack backtrace:\nCPU: 1 PID: 1142 Comm: udevd Not tainted 6.1.74-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall Trace:\n <TASK>\n  [<ffffffff85b85f14>] __dump_stack lib/dump_stack.c:88 [inline]\n  [<ffffffff85b85f14>] dump_stack_lvl+0x1b1/0x28f lib/dump_stack.c:106\n  [<ffffffff85b86007>] dump_stack+0x15/0x1e lib/dump_stack.c:113\n  [<ffffffff81802299>] lockdep_rcu_suspicious+0x1b9/0x260 kernel/locking/lockdep.c:6592\n  [<ffffffff84f0054c>] qdisc_lookup+0xac/0x6f0 net/sched/sch_api.c:305\n  [<ffffffff84f037c3>] qdisc_tree_reduce_backlog+0x243/0x580 net/sched/sch_api.c:811\n  [<ffffffff84f5b78c>] pfifo_tail_enqueue+0x32c/0x4b0 net/sched/sch_fifo.c:51\n  [<ffffffff84fbcf63>] qdisc_enqueue include/net/sch_generic.h:833 [inline]\n  [<ffffffff84fbcf63>] netem_dequeue+0xeb3/0x15d0 net/sched/sch_netem.c:723\n  [<ffffffff84eecab9>] dequeue_skb net/sched/sch_generic.c:292 [inline]\n  [<ffffffff84eecab9>] qdisc_restart net/sched/sch_generic.c:397 [inline]\n  [<ffffffff84eecab9>] __qdisc_run+0x249/0x1e60 net/sched/sch_generic.c:415\n  [<ffffffff84d7aa96>] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125\n  [<ffffffff84d85d29>] net_tx_action+0x7c9/0x970 net/core/dev.c:5313\n  [<ffffffff85e002bd>] __do_softirq+0x2bd/0x9bd kernel/softirq.c:616\n  [<ffffffff81568bca>] invoke_softirq kernel/softirq.c:447 [inline]\n  [<ffffffff81568bca>] __irq_exit_rcu+0xca/0x230 kernel/softirq.c:700\n  [<ffffffff81568ae9>] irq_exit_rcu+0x9/0x20 kernel/softirq.c:712\n  [<ffffffff85b89f52>] sysvec_apic_timer_interrupt+0x42/0x90 arch/x86/kernel/apic/apic.c:1107\n  [<ffffffff85c00ccb>] asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:656",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
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        "1:6.1.47-1+rpt4",
        "1:6.1.54-1+rpt2",
        "1:6.1.58-1+rpt2",
        "1:6.1.63-1+rpt1",
        "1:6.1.73-1+rpt1",
        "1:6.6.20-1+rpt1"
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      "ecosystem_specific": {
        "binaries": [
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            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.85"
          },
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            "compiled_filter": false
          },
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          },
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            "linux_commit": null,
            "upstream_version": "6.1.63",
            "assessment": "upstream version (no usable Linux commit)",
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          },
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            "assessment": "upstream version (no usable Linux commit)",
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            "upstream_fixed": "6.6.26"
          }
        }
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    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-35892"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b7d1ce2cc7192e8a037faa3f5d3ba72c25976460"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c040b99461a5bfc14c2d0cbb1780fcc3a4706c7e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/07696415526bee0607e495017369c7303a4792e1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7eb322360b0266481e560d1807ee79e0cef5742b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-24T06:48:58Z"
  }
}