{"id":"DEBIAN-CVE-2024-35892","details":"In the Linux kernel, the following vulnerability has been resolved:  net/sched: fix lockdep splat in qdisc_tree_reduce_backlog()  qdisc_tree_reduce_backlog() is called with the qdisc lock held, not RTNL.  We must use qdisc_lookup_rcu() instead of qdisc_lookup()  syzbot reported:  WARNING: suspicious RCU usage 6.1.74-syzkaller #0 Not tainted ----------------------------- net/sched/sch_api.c:305 suspicious rcu_dereference_protected() usage!  other info that might help us debug this:  rcu_scheduler_active = 2, debug_locks = 1 3 locks held by udevd/1142:   #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]   #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]   #0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: net_tx_action+0x64a/0x970 net/core/dev.c:5282   #1: ffff888171861108 (&sch-\u003eq.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]   #1: ffff888171861108 (&sch-\u003eq.lock){+.-.}-{2:2}, at: net_tx_action+0x754/0x970 net/core/dev.c:5297   #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]   #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]   #2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: qdisc_tree_reduce_backlog+0x84/0x580 net/sched/sch_api.c:792  stack backtrace: CPU: 1 PID: 1142 Comm: udevd Not tainted 6.1.74-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace:  \u003cTASK\u003e   [\u003cffffffff85b85f14\u003e] __dump_stack lib/dump_stack.c:88 [inline]   [\u003cffffffff85b85f14\u003e] dump_stack_lvl+0x1b1/0x28f lib/dump_stack.c:106   [\u003cffffffff85b86007\u003e] dump_stack+0x15/0x1e lib/dump_stack.c:113   [\u003cffffffff81802299\u003e] lockdep_rcu_suspicious+0x1b9/0x260 kernel/locking/lockdep.c:6592   [\u003cffffffff84f0054c\u003e] qdisc_lookup+0xac/0x6f0 net/sched/sch_api.c:305   [\u003cffffffff84f037c3\u003e] qdisc_tree_reduce_backlog+0x243/0x580 net/sched/sch_api.c:811   [\u003cffffffff84f5b78c\u003e] pfifo_tail_enqueue+0x32c/0x4b0 net/sched/sch_fifo.c:51   [\u003cffffffff84fbcf63\u003e] qdisc_enqueue include/net/sch_generic.h:833 [inline]   [\u003cffffffff84fbcf63\u003e] netem_dequeue+0xeb3/0x15d0 net/sched/sch_netem.c:723   [\u003cffffffff84eecab9\u003e] dequeue_skb net/sched/sch_generic.c:292 [inline]   [\u003cffffffff84eecab9\u003e] qdisc_restart net/sched/sch_generic.c:397 [inline]   [\u003cffffffff84eecab9\u003e] __qdisc_run+0x249/0x1e60 net/sched/sch_generic.c:415   [\u003cffffffff84d7aa96\u003e] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125   [\u003cffffffff84d85d29\u003e] net_tx_action+0x7c9/0x970 net/core/dev.c:5313   [\u003cffffffff85e002bd\u003e] __do_softirq+0x2bd/0x9bd kernel/softirq.c:616   [\u003cffffffff81568bca\u003e] invoke_softirq kernel/softirq.c:447 [inline]   [\u003cffffffff81568bca\u003e] __irq_exit_rcu+0xca/0x230 kernel/softirq.c:700   [\u003cffffffff81568ae9\u003e] irq_exit_rcu+0x9/0x20 kernel/softirq.c:712   [\u003cffffffff85b89f52\u003e] sysvec_apic_timer_interrupt+0x42/0x90 arch/x86/kernel/apic/apic.c:1107   [\u003cffffffff85c00ccb\u003e] asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:656","modified":"2026-09-15T09:03:08.357774600Z","published":"2024-05-19T09:15:10.230Z","upstream":["CVE-2024-35892"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2024-35892"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.85-1"}]}],"versions":["6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-35892.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.8.9-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-35892.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.8.9-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-35892.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}