{"id":"DEBIAN-CVE-2021-47512","details":"In the Linux kernel, the following vulnerability has been resolved:  net/sched: fq_pie: prevent dismantle issue  For some reason, fq_pie_destroy() did not copy working code from pie_destroy() and other qdiscs, thus causing elusive bug.  Before calling del_timer_sync(&q-\u003eadapt_timer), we need to ensure timer will not rearm itself.  rcu: INFO: rcu_preempt self-detected stall on CPU rcu:    0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579         (t=10501 jiffies g=13085 q=3989) NMI backtrace for cpu 0 CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace:  \u003cIRQ\u003e  __dump_stack lib/dump_stack.c:88 [inline]  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106  nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111  nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62  trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]  rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343  print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]  check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]  rcu_pending kernel/rcu/tree.c:3878 [inline]  rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597  update_process_times+0x16d/0x200 kernel/time/timer.c:1785  tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226  tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428  __run_hrtimer kernel/time/hrtimer.c:1685 [inline]  __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749  hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]  __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103  sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097  \u003c/IRQ\u003e  \u003cTASK\u003e  asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:write_comp_data kernel/kcov.c:221 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273 Code: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08 \u003ce8\u003e 4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00 RSP: 0018:ffffc90000d27b28 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000 RDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003 RBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000  pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418  fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383  call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421  expire_timers kernel/time/timer.c:1466 [inline]  __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734  __run_timers kernel/time/timer.c:1715 [inline]  run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747  __do_softirq+0x29b/0x9c2 kernel/softirq.c:558  run_ksoftirqd kernel/softirq.c:921 [inline]  run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913  smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164  kthread+0x405/0x4f0 kernel/kthread.c:327  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295  \u003c/TASK\u003e","modified":"2026-09-01T20:04:37.892182083Z","published":"2024-05-24T15:15:12.487Z","upstream":["CVE-2021-47512"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-47512"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47512.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47512.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47512.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"}]}