================================================================== 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 ffff8881e5e7b1c8 by task syz.0.257/1341 CPU: 1 PID: 1341 Comm: syz.0.257 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 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: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x51/0x80 kernel/locking/spinlock.c:191 Code: 89 fe 48 c7 c7 b0 2d cb 85 e8 ab 7f 62 fd 4c 89 f7 48 83 3d 40 34 a0 01 00 74 34 e8 0d 38 1d fd 66 90 48 89 5d e8 ff 75 e8 9d 01 00 00 00 e8 e5 7a 16 fd 65 8b 05 fa 93 d7 7b 85 c0 74 09 48 RSP: 0018:ffff8881d7f2f2c0 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000a06 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000a06 RDI: ffff8881e0daa498 RBP: ffff8881d7f2f2d8 R08: dffffc0000000000 R09: ffffed103ba5e048 R10: ffffed103ba5e048 R11: 1ffff1103ba5e047 R12: 0000000000000a06 R13: ffffea0007354908 R14: ffff8881e0daa490 R15: ffff8881e0daa498 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] delete_from_page_cache+0xc9/0x100 mm/filemap.c:274 truncate_inode_page+0x5d/0x70 mm/truncate.c:225 shmem_undo_range+0x6ad/0x1860 mm/shmem.c:869 shmem_truncate_range mm/shmem.c:997 [inline] shmem_evict_inode+0x204/0x9a0 mm/shmem.c:1097 evict+0x465/0x880 fs/inode.c:610 iput_final fs/inode.c:1652 [inline] iput+0x67d/0x810 fs/inode.c:1678 dentry_unlink_inode+0x2ca/0x370 fs/dcache.c:378 __dentry_kill+0x43e/0x640 fs/dcache.c:583 dentry_kill+0xc0/0x2a0 fs/dcache.c:677 dput+0x42/0x80 fs/dcache.c:864 __fput+0x4ba/0x730 fs/file_table.c:294 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x146/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa43/0x2660 kernel/exit.c:861 do_group_exit+0x13e/0x300 kernel/exit.c:984 get_signal+0xdee/0x13d0 kernel/signal.c:2738 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194 ret_from_intr+0x1c/0x1c RIP: 0033:0x7faa916cd971 Code: Bad RIP value. RSP: 002b:0000200000000030 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007faa918f4fa0 RCX: 00007faa916cd969 RDX: 0000200000000040 RSI: 0000200000000030 RDI: 0000000004000000 RBP: 00007faa9174fab1 R08: 00002000000000c0 R09: 00002000000000c0 R10: 0000200000000080 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000001 R14: 00007faa918f4fa0 R15: 00007ffc01744d18 The buggy address belongs to the page: page:ffffea0007979ec0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 ffffea0007af8308 ffffea0007149e08 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 bpf_array_alloc_percpu kernel/bpf/arraymap.c:35 [inline] array_map_alloc+0x39d/0x6d0 kernel/bpf/arraymap.c:136 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: ffff8881e5e7b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e5e7b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881e5e7b180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881e5e7b200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e5e7b280: 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 1ebe34067 P4D 1ebe34067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1341 Comm: syz.0.257 Tainted: G B 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:ffff8881f6f09cf0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881dea9af40 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e5e7b1c0 RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 00000000ffff9d98 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e5e7b1c0 FS: 00007faa8fd366c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001d7553000 CR4: 00000000003406a0 DR0: 0000200000000300 DR1: 0000200000000300 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 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:unwind_get_return_address+0x6d/0x90 arch/x86/kernel/unwind_frame.c:20 Code: 5f 00 48 8b 3b e8 53 62 11 00 85 c0 74 14 43 80 3c 37 00 74 08 48 89 df e8 40 de 5f 00 48 8b 03 eb 02 31 c0 5b 41 5e 41 5f 5d 89 d9 80 e1 07 80 c1 03 38 c1 7c ac 48 89 df e8 fe dd 5f 00 eb RSP: 0018:ffff8881d7f2ede0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff8193fc45 RBX: ffff8881d7f2eea0 RCX: 06e10a8ae28ff601 RDX: ffff8881d7f2f9e8 RSI: 1ffff1103afe5dbe RDI: ffffffff8193fc45 RBP: ffff8881d7f2ee70 R08: dffffc0000000000 R09: ffff8881d7f2ede8 R10: ffffed103afe5dc9 R11: 1ffff1103afe5dbd R12: ffff8881dea9af40 R13: 1ffff1103afe5dd0 R14: ffffffff814fbbf0 R15: ffff8881d7f2ede8 stack_trace_save+0xaa/0xf0 kernel/stacktrace.c:123 save_stack+0x97/0x560 mm/page_owner.c:122 __reset_page_owner+0x23/0x110 mm/page_owner.c:149 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_list+0x110/0x4c0 mm/page_alloc.c:3154 release_pages+0xa62/0xaa0 mm/swap.c:842 __pagevec_release+0xbb/0x140 mm/swap.c:862 pagevec_release include/linux/pagevec.h:88 [inline] shmem_undo_range+0x7d8/0x1860 mm/shmem.c:875 shmem_truncate_range mm/shmem.c:997 [inline] shmem_evict_inode+0x204/0x9a0 mm/shmem.c:1097 evict+0x465/0x880 fs/inode.c:610 iput_final fs/inode.c:1652 [inline] iput+0x67d/0x810 fs/inode.c:1678 dentry_unlink_inode+0x2ca/0x370 fs/dcache.c:378 __dentry_kill+0x43e/0x640 fs/dcache.c:583 dentry_kill+0xc0/0x2a0 fs/dcache.c:677 dput+0x42/0x80 fs/dcache.c:864 __fput+0x4ba/0x730 fs/file_table.c:294 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x146/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa43/0x2660 kernel/exit.c:861 do_group_exit+0x13e/0x300 kernel/exit.c:984 get_signal+0xdee/0x13d0 kernel/signal.c:2738 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194 ret_from_intr+0x1c/0x1c RIP: 0033:0x7faa916cd971 Code: 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 48 3d 01 f0 ff ff 73 01 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:0000200000000030 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007faa918f4fa0 RCX: 00007faa916cd969 RDX: 0000200000000040 RSI: 0000200000000030 RDI: 0000000004000000 RBP: 00007faa9174fab1 R08: 00002000000000c0 R09: 00002000000000c0 R10: 0000200000000080 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000001 R14: 00007faa918f4fa0 R15: 00007ffc01744d18 Modules linked in: CR2: 0000000000000000 ---[ end trace cd3251eb06230fc6 ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6f09cf0 EFLAGS: 00010206 RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881dea9af40 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e5e7b1c0 RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 00000000ffff9d98 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e5e7b1c0 FS: 00007faa8fd366c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001d7553000 CR4: 00000000003406a0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 ---------------- Code disassembly (best guess): 0: 89 fe mov %edi,%esi 2: 48 c7 c7 b0 2d cb 85 mov $0xffffffff85cb2db0,%rdi 9: e8 ab 7f 62 fd call 0xfd627fb9 e: 4c 89 f7 mov %r14,%rdi 11: 48 83 3d 40 34 a0 01 cmpq $0x0,0x1a03440(%rip) # 0x1a03459 18: 00 19: 74 34 je 0x4f 1b: e8 0d 38 1d fd call 0xfd1d382d 20: 66 90 xchg %ax,%ax 22: 48 89 5d e8 mov %rbx,-0x18(%rbp) 26: ff 75 e8 push -0x18(%rbp) 29: 9d popf * 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction 2f: e8 e5 7a 16 fd call 0xfd167b19 34: 65 8b 05 fa 93 d7 7b mov %gs:0x7bd793fa(%rip),%eax # 0x7bd79435 3b: 85 c0 test %eax,%eax 3d: 74 09 je 0x48 3f: 48 rex.W