================================================================== 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 ffff8881e3b8f1c8 by task syz.0.1066/4258 CPU: 0 PID: 4258 Comm: syz.0.1066 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:ffff8881c2d7f2c0 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000a06 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000a06 RDI: ffff8881eeacab88 RBP: ffff8881c2d7f2d8 R08: dffffc0000000000 R09: ffffed10392c53b8 R10: ffffed10392c53b8 R11: 1ffff110392c53b7 R12: 0000000000000a06 R13: ffffea00072b37c8 R14: ffff8881eeacab80 R15: ffff8881eeacab88 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: 0033:0x7f539be10971 Code: Bad RIP value. RSP: 002b:00000000fffffeb0 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f539c037fa0 RCX: 00007f539be10969 RDX: 0000000000000000 RSI: 00000000fffffeb0 RDI: 0000000002000400 RBP: 00007f539be92ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f539c037fa0 R15: 00007fff34e56e68 The buggy address belongs to the page: page:ffffea00078ee3c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 0000000000000000 ffffea00078ee388 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 0x152dc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__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] bpf_check+0xfb/0x9cf0 kernel/bpf/verifier.c:9561 bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline] __se_sys_bpf+0x435/0x570 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_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 bpf_check+0x8371/0x9cf0 kernel/bpf/verifier.c:9731 bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline] __se_sys_bpf+0x435/0x570 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 Memory state around the buggy address: ffff8881e3b8f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e3b8f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881e3b8f180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881e3b8f200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e3b8f280: 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 0 P4D 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 0 PID: 4465 Comm: syz.1.1130 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:ffff8881f6e09cf0 EFLAGS: 00010202 RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881c9d26e40 RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881e3b8f1c0 RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffbf98 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e3b8f1c0 FS: 00007f2defb0f6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000005c0e000 CR4: 00000000003406b0 DR0: 0000200000000300 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 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:update_stack_state+0x205/0x4c0 arch/x86/kernel/unwind_frame.c:224 Code: 8b 55 98 4c 39 fa 0f 93 c1 20 c1 4c 39 f2 0f 92 c0 20 c8 3c 01 75 17 48 8b 8d 60 ff ff ff 4c 39 f9 0f 97 c0 4c 39 f1 0f 96 c1 <84> c8 75 6e 49 bd 00 00 00 00 00 fc ff df 48 8b 85 50 ff ff ff 42 RSP: 0018:ffff8881d82c6e58 EFLAGS: 00000283 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: ffff8881d82c6fc8 RCX: ffff8881d82c7601 RDX: ffff8881d82c7610 RSI: 1ffff1103b058dfa RDI: ffff8881d82c7020 RBP: ffff8881d82c6f28 R08: dffffc0000000000 R09: ffff8881d82c6fc8 R10: ffffed103b058e05 R11: 1ffff1103b058df9 R12: ffff8881d82c6fd0 R13: 0000000000000001 R14: ffff8881d82c8000 R15: ffff8881d82c0000 unwind_next_frame+0x3f7/0x760 arch/x86/kernel/unwind_frame.c:311 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0xf0 kernel/stacktrace.c:123 save_stack+0x97/0x560 mm/page_owner.c:122 __set_page_owner+0x39/0x1e0 mm/page_owner.c:191 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] __get_free_pages+0xe/0x30 mm/page_alloc.c:4938 tlb_next_batch mm/mmu_gather.c:29 [inline] __tlb_remove_page_size+0x17b/0x300 mm/mmu_gather.c:83 __tlb_remove_page include/asm-generic/tlb.h:426 [inline] zap_pte_range mm/memory.c:1108 [inline] zap_pmd_range mm/memory.c:1222 [inline] zap_pud_range mm/memory.c:1251 [inline] zap_p4d_range mm/memory.c:1272 [inline] unmap_page_range+0xf7c/0x1b20 mm/memory.c:1293 unmap_single_vma mm/memory.c:1338 [inline] unmap_vmas+0x245/0x340 mm/memory.c:1370 exit_mmap+0x2bb/0x520 mm/mmap.c:3191 __mmput+0x92/0x2e0 kernel/fork.c:1101 mmput+0x47/0x60 kernel/fork.c:1122 exit_mm kernel/exit.c:538 [inline] do_exit+0x99f/0x2660 kernel/exit.c:848 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 syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f2df14a6969 Code: Bad RIP value. RSP: 002b:00007f2defb0f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f2df16cdfa8 RCX: 00007f2df14a6969 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2df16cdfa8 RBP: 00007f2df16cdfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2df16cdfac R13: 0000000000000000 R14: 00007ffdc3d7e970 R15: 00007ffdc3d7ea58 Modules linked in: CR2: 0000000000000000 ---[ end trace df8c23d4110ece06 ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010202 RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881c9d26e40 RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881e3b8f1c0 RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003 R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffbf98 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e3b8f1c0 FS: 00007f2defb0f6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000005c0e000 CR4: 00000000003406b0 DR0: 0000200000000300 DR1: 0000000000000000 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