================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline] BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541 Write of size 8 at addr ffff8881e87c71c8 by task kauditd/23 CPU: 0 PID: 23 Comm: kauditd Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack+0x1e/0x20 lib/dump_stack.c:77 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384 __kasan_report+0xef/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137 hlist_add_head include/linux/list.h:814 [inline] enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541 __internal_add_timer kernel/time/timer.c:554 [inline] internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604 __mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065 mod_timer+0x1f/0x30 kernel/time/timer.c:1117 br_hello_timer_expired+0x120/0x180 net/bridge/br_stp_timer.c:40 call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x81d/0xb60 kernel/time/timer.c:1817 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830 __do_softirq+0x236/0x660 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x197/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:539 [inline] smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834 RIP: 0010:native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline] RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline] RIP: 0010:console_unlock+0x9ea/0xe80 kernel/printk/printk.c:2527 Code: 64 56 86 e8 48 73 e1 02 f6 c3 01 48 8b 5c 24 28 0f 85 61 04 00 00 e8 55 f9 15 00 e8 80 5a 00 00 48 89 5c 24 70 ff 74 24 70 9d d0 f7 ff ff e8 3c f9 15 00 48 c7 05 d1 d7 0c 05 00 00 00 00 e9 RSP: 0018:ffff8881f23ef8e0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff8149e019 RBX: 0000000000000293 RCX: ffff8881f5e18fc0 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: ffff8881f23efa90 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103e47df0c R11: 1ffff1103e47df0c R12: 0000000000000000 R13: ffffffff85eefb30 R14: ffffffff8267bbc0 R15: dffffc0000000000 vprintk_emit+0x1be/0x380 kernel/printk/printk.c:2032 vprintk_default+0x28/0x30 kernel/printk/printk.c:2059 vprintk_func+0x19a/0x1e0 kernel/printk/printk_safe.c:393 printk+0xcc/0x110 kernel/printk/printk.c:2092 kauditd_printk_skb kernel/audit.c:543 [inline] kauditd_hold_skb+0x1bc/0x210 kernel/audit.c:578 kauditd_send_queue+0x299/0x2e0 kernel/audit.c:763 kauditd_thread+0x4ff/0x870 kernel/audit.c:887 kthread+0x31e/0x3a0 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 The buggy address belongs to the page: page:ffffea0007a1f1c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 0000000000000000 ffffea0007a1f1c8 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 2, migratetype Unmovable, gfp_mask 0x146dc0(GFP_USER|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP|__GFP_ZERO) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x35e/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894 __alloc_pages include/linux/gfp.h:503 [inline] __alloc_pages_node include/linux/gfp.h:516 [inline] alloc_pages_node include/linux/gfp.h:530 [inline] kmalloc_order mm/slab_common.c:1342 [inline] kmalloc_order_trace+0x31/0x100 mm/slab_common.c:1358 kmalloc_large include/linux/slab.h:485 [inline] __kmalloc+0x162/0x2f0 mm/slub.c:3902 __kmalloc_node include/linux/slab.h:422 [inline] kmalloc_node include/linux/slab.h:599 [inline] kvmalloc_node+0x88/0xf0 mm/util.c:596 kvmalloc include/linux/mm.h:761 [inline] kvzalloc include/linux/mm.h:769 [inline] alloc_netdev_mqs+0x88/0xc50 net/core/dev.c:9629 tun_set_iff+0x535/0xe00 drivers/net/tun.c:2893 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] __free_pages_ok+0x7e4/0x910 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4956 [inline] __free_pages+0x8c/0x110 mm/page_alloc.c:4962 kfree+0x1ca/0x260 mm/slub.c:4068 kvfree+0x4c/0x50 mm/util.c:625 netdev_freemem+0x3f/0x60 net/core/dev.c:9583 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1743 device_release+0x70/0x1a0 drivers/base/core.c:1776 kobject_cleanup lib/kobject.c:716 [inline] kobject_release lib/kobject.c:747 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1fe/0x2c0 lib/kobject.c:764 put_device+0x1f/0x30 drivers/base/core.c:3010 free_netdev+0x27e/0x320 net/core/dev.c:9746 tun_set_iff+0x87c/0xe00 drivers/net/tun.c:2924 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290 Memory state around the buggy address: ffff8881e87c7080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e87c7100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881e87c7180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881e87c7200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e87c7280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ---------------- Code disassembly (best guess): 0: 64 56 fs push %rsi 2: 86 e8 xchg %ch,%al 4: 48 73 e1 rex.W jae 0xffffffe8 7: 02 f6 add %dh,%dh 9: c3 ret a: 01 48 8b add %ecx,-0x75(%rax) d: 5c pop %rsp e: 24 28 and $0x28,%al 10: 0f 85 61 04 00 00 jne 0x477 16: e8 55 f9 15 00 call 0x15f970 1b: e8 80 5a 00 00 call 0x5aa0 20: 48 89 5c 24 70 mov %rbx,0x70(%rsp) 25: ff 74 24 70 push 0x70(%rsp) 29: 9d popf * 2a: e9 d0 f7 ff ff jmp 0xfffff7ff <-- trapping instruction 2f: e8 3c f9 15 00 call 0x15f970 34: 48 c7 05 d1 d7 0c 05 movq $0x0,0x50cd7d1(%rip) # 0x50cd810 3b: 00 00 00 00 3f: e9 .byte 0xe9