================================================================== 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 ffff8881d58331c8 by task syz.7.1297/4992 CPU: 0 PID: 4992 Comm: syz.7.1297 Tainted: G W 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 can_stat_update+0xbab/0xc40 net/can/proc.c:186 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: 0033:0x7f66ff59795e Code: 45 31 ff 45 31 f6 44 0f b6 e6 85 c0 0f 84 9e 00 00 00 44 89 f9 49 8b 50 30 4c 89 f0 49 03 14 ca 80 3d 4d 92 34 00 00 49 89 d6 <48> 89 d5 74 28 25 ff 0f 00 00 83 f0 3d 8d 04 c0 89 c5 c1 ed 04 31 RSP: 002b:00007fff46be89e0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: ffffffff82209dad RBX: 00007f670040e720 RCX: 0000000000004dc9 RDX: ffffffff82209b0e RSI: ffffffff82209aae RDI: 0000000000000007 RBP: ffffffff82209aae R08: 00007f66ff8df038 R09: 00007f66ff8cb000 R10: 00007f66fed28008 R11: 0000000000000007 R12: 0000000000000007 R13: 0000000000000000 R14: ffffffff82209b0e R15: 0000000000004dc9 The buggy address belongs to the page: page:ffffea0007560cc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 ffffea0007900d08 ffffea00079eee88 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 0, migratetype Unmovable, gfp_mask 0x102cc2(GFP_HIGHUSER|__GFP_NOWARN) 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] pcpu_alloc_pages mm/percpu-vm.c:94 [inline] pcpu_populate_chunk+0x1b6/0xce0 mm/percpu-vm.c:284 pcpu_alloc+0x8ec/0x1120 mm/percpu.c:1714 __alloc_percpu_gfp+0x25/0x30 mm/percpu.c:1783 prealloc_init+0x24b/0x810 kernel/bpf/hashtab.c:154 htab_map_alloc+0x65f/0x940 kernel/bpf/hashtab.c:385 find_and_alloc_map kernel/bpf/syscall.c:122 [inline] map_create+0x2d8/0x980 kernel/bpf/syscall.c:573 __do_sys_bpf kernel/bpf/syscall.c:2873 [inline] __se_sys_bpf+0x2dc/0x570 kernel/bpf/syscall.c:2849 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849 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_pcp_prepare mm/page_alloc.c:1233 [inline] free_unref_page_prepare+0x2a9/0x3a0 mm/page_alloc.c:3085 free_unref_page mm/page_alloc.c:3134 [inline] free_the_page mm/page_alloc.c:4954 [inline] __free_pages+0xaa/0x110 mm/page_alloc.c:4962 pcpu_free_pages mm/percpu-vm.c:64 [inline] pcpu_depopulate_chunk mm/percpu-vm.c:328 [inline] pcpu_balance_workfn+0x8c7/0x14b0 mm/percpu.c:1865 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436 kthread+0x31e/0x3a0 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Memory state around the buggy address: ffff8881d5833080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881d5833100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881d5833180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881d5833200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881d5833280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 1e9816067 P4D 1e9816067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 0 PID: 10 Comm: ksoftirqd/0 Tainted: G B W 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5dd7bd0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881f5dc6e40 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881d58331c0 RBP: ffff8881f5dd7c10 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103ebbaf74 R11: 1ffff1103ebbaf74 R12: 00000000ffffb9b8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d58331c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001bd0b6000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: 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 run_ksoftirqd+0x23/0x30 kernel/softirq.c:603 smpboot_thread_fn+0x474/0x850 kernel/smpboot.c:165 kthread+0x31e/0x3a0 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Modules linked in: CR2: 0000000000000000 ---[ end trace fece60d3cbe35d5f ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5dd7bd0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881f5dc6e40 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881d58331c0 RBP: ffff8881f5dd7c10 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103ebbaf74 R11: 1ffff1103ebbaf74 R12: 00000000ffffb9b8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d58331c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001bd0b6000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600