================================================================== BUG: KASAN: slab-use-after-free in timer_is_static_object+0x35/0x80 kernel/time/timer.c:691 Read of size 8 at addr ffff888038685c98 by task syz.3.7750/6020 CPU: 1 UID: 0 PID: 6020 Comm: syz.3.7750 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 timer_is_static_object+0x35/0x80 kernel/time/timer.c:691 lookup_object_or_alloc lib/debugobjects.c:679 [inline] debug_object_activate+0x141/0x580 lib/debugobjects.c:820 debug_timer_activate kernel/time/timer.c:793 [inline] __mod_timer+0xa4f/0xf30 kernel/time/timer.c:1124 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:0xffffffffa0003774 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 41 ff e3 cc 41 ff e3 cc 41 ff e3 cc 41 ff e3 cc 41 ff e3 cc <41> ff e3 cc 41 ff e3 cc 41 ff e3 cc cc cc cc cc cc cc cc cc cc cc RSP: 0018:ffffc9000ff1e640 EFLAGS: 00000286 RAX: ffffffff898f81d8 RBX: ffffc9000ff1e700 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff898f81d8 RDI: ffffc9000ff1e700 RBP: ffffc9000ff1e6d0 R08: ffffc9000ff1ebd8 R09: 0000000000000000 R10: ffffc9000ff1e698 R11: ffffffff81b0b100 R12: ffff888035d2bc80 R13: 00000000ffffffff R14: ffffffff81b0b100 R15: ffffc9000ff1e648 Allocated by task 31185: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5339 kmalloc_noprof include/linux/slab.h:962 [inline] rose_add_node+0x23c/0xf00 net/rose/rose_route.c:85 rose_rt_ioctl+0xd35/0x12a0 net/rose/rose_route.c:748 rose_ioctl+0x3fb/0x8f0 net/rose/af_rose.c:1382 sock_do_ioctl+0x101/0x320 net/socket.c:1254 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6037: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2687 [inline] slab_free mm/slub.c:6124 [inline] kfree+0x1c1/0x630 mm/slub.c:6442 rose_neigh_put include/net/rose.h:166 [inline] rose_timer_expiry+0x4cb/0x600 net/rose/rose_timer.c:183 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 The buggy address belongs to the object at ffff888038685c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 152 bytes inside of freed 512-byte region [ffff888038685c00, ffff888038685e00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x38684 head: order:2 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 ffff88813fea8c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fea8c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0000e1a101 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 21000, tgid 21000 (dhcpcd-run-hook), ts 569594242051, free_ts 569529973791 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab+0x77/0x660 mm/slub.c:3444 new_slab mm/slub.c:3502 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5334 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1200 [inline] alloc_bprm+0x7d/0x5c0 fs/exec.c:1405 class_bprm_constructor fs/exec.c:1466 [inline] do_execveat_common+0x175/0x690 fs/exec.c:1799 __do_sys_execve fs/exec.c:1930 [inline] __se_sys_execve fs/exec.c:1924 [inline] __x64_sys_execve+0x97/0xc0 fs/exec.c:1924 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 6962 tgid 6962 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 build_detached_freelist+0x1cb/0x1f0 mm/slub.c:6874 kmem_cache_free_bulk+0xf9/0x1170 mm/slub.c:6961 kfree_bulk include/linux/slab.h:835 [inline] kvfree_rcu_bulk+0xe5/0x1b0 mm/slab_common.c:1502 kvfree_rcu_drain_ready mm/slab_common.c:1704 [inline] kfree_rcu_monitor+0x211/0x2a0 mm/slab_common.c:1777 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888038685b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888038685c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888038685c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888038685d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888038685d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: cc int3 3: cc int3 4: cc int3 5: cc int3 6: cc int3 7: cc int3 8: cc int3 9: cc int3 a: cc int3 b: cc int3 c: cc int3 d: cc int3 e: cc int3 f: cc int3 10: cc int3 11: cc int3 12: cc int3 13: cc int3 14: cc int3 15: cc int3 16: 41 ff e3 jmp *%r11 19: cc int3 1a: 41 ff e3 jmp *%r11 1d: cc int3 1e: 41 ff e3 jmp *%r11 21: cc int3 22: 41 ff e3 jmp *%r11 25: cc int3 26: 41 ff e3 jmp *%r11 29: cc int3 * 2a: 41 ff e3 jmp *%r11 <-- trapping instruction 2d: cc int3 2e: 41 ff e3 jmp *%r11 31: cc int3 32: 41 ff e3 jmp *%r11 35: cc int3 36: cc int3 37: cc int3 38: cc int3 39: cc int3 3a: cc int3 3b: cc int3 3c: cc int3 3d: cc int3 3e: cc int3 3f: cc int3