================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline] BUG: KASAN: use-after-free in enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 Write of size 8 at addr ffff8881da22b1c8 by task syz.1.3420/10308 CPU: 0 PID: 10308 Comm: syz.1.3420 Tainted: G W 5.4.274-syzkaller-00002-g6f97bd951d82 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 hlist_add_head include/linux/list.h:814 [inline] enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 __internal_add_timer kernel/time/timer.c:554 [inline] internal_add_timer+0x240/0x430 kernel/time/timer.c:604 __mod_timer+0x6f1/0x13e0 kernel/time/timer.c:1065 call_timer_fn+0x36/0x390 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x879/0xbe0 kernel/time/timer.c:1817 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x195/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:538 [inline] smp_apic_timer_interrupt+0x11a/0x460 arch/x86/kernel/apic/apic.c:1149 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834 RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65 Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 RSP: 0018:ffff8881d38974f0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff813a05cc RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000001000 RSI: 00000000000000cc RDI: ffffffffa0099000 RBP: 0000000000001000 R08: dffffc0000000000 R09: ffffffffa0098000 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffffa0098000 R15: 0000000000000fff jit_fill_hole+0x1c/0x20 arch/x86/net/bpf_jit_comp.c:191 bpf_jit_binary_alloc+0xbe/0x1a0 kernel/bpf/core.c:833 bpf_int_jit_compile+0x8169/0x8c40 arch/x86/net/bpf_jit_comp.c:1179 bpf_prog_select_runtime+0x654/0x900 kernel/bpf/core.c:1782 bpf_prog_load kernel/bpf/syscall.c:1728 [inline] __do_sys_bpf kernel/bpf/syscall.c:2891 [inline] __se_sys_bpf+0x8193/0xbcb0 kernel/bpf/syscall.c:2849 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f9098f28d39 Code: ff ff c3 66 2e 0f 1f 84 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 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f90981aa048 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f90990b6fa0 RCX: 00007f9098f28d39 RDX: 0000000000000090 RSI: 00000000200000c0 RDI: 0000000000000005 RBP: 00007f9098fa9766 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f90990b6fa0 R15: 00007ffd639bc348 Allocated by task 348: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842 getname_flags+0xb8/0x4e0 fs/namei.c:141 user_path_at_empty+0x28/0x50 fs/namei.c:2703 user_path_at include/linux/namei.h:49 [inline] vfs_statx+0x115/0x210 fs/stat.c:187 vfs_fstatat include/linux/fs.h:3380 [inline] __do_sys_newfstatat fs/stat.c:367 [inline] __se_sys_newfstatat+0xce/0x770 fs/stat.c:361 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 348: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096 putname fs/namei.c:262 [inline] filename_lookup+0x50e/0x6e0 fs/namei.c:2432 user_path_at include/linux/namei.h:49 [inline] vfs_statx+0x115/0x210 fs/stat.c:187 vfs_fstatat include/linux/fs.h:3380 [inline] __do_sys_newfstatat fs/stat.c:367 [inline] __se_sys_newfstatat+0xce/0x770 fs/stat.c:361 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 The buggy address belongs to the object at ffff8881da22a200 which belongs to the cache names_cache of size 4096 The buggy address is located 4040 bytes inside of 4096-byte region [ffff8881da22a200, ffff8881da22b200) The buggy address belongs to the page: page:ffffea0007688a00 refcount:1 mapcount:0 mapping:ffff8881f5d04780 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d04780 raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x109/0x250 mm/slub.c:2842 getname_flags+0xb8/0x4e0 fs/namei.c:141 user_path_at_empty+0x28/0x50 fs/namei.c:2703 user_path_at include/linux/namei.h:49 [inline] vfs_statx+0x115/0x210 fs/stat.c:187 vfs_fstatat include/linux/fs.h:3380 [inline] __do_sys_newfstatat fs/stat.c:367 [inline] __se_sys_newfstatat+0xce/0x770 fs/stat.c:361 do_syscall_64+0xca/0x1c0 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+0x847/0x950 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4955 [inline] __free_pages+0x91/0x140 mm/page_alloc.c:4961 device_release+0x6b/0x190 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+0x1e6/0x2f0 lib/kobject.c:764 netdev_run_todo+0xc44/0xdf0 net/core/dev.c:9469 tun_detach drivers/net/tun.c:766 [inline] tun_chr_close+0xc1/0x130 drivers/net/tun.c:3558 __fput+0x262/0x680 fs/file_table.c:281 task_work_run+0x140/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xcaf/0x2bc0 kernel/exit.c:859 do_group_exit+0x138/0x300 kernel/exit.c:982 get_signal+0xdb1/0x1440 kernel/signal.c:2735 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881da22b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881da22b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881da22b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881da22b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881da22b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== 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: 10 Comm: ksoftirqd/0 Tainted: G B W 5.4.274-syzkaller-00002-g6f97bd951d82 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5ddfb58 EFLAGS: 00010206 RAX: ffffffff8154d7aa RBX: 0000000000000100 RCX: ffff8881f5dc8000 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881da22b1c0 RBP: ffff8881f5ddfd08 R08: ffffffff8154d3ee R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffe578 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881da22b1c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ed683000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: call_timer_fn+0x36/0x390 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x879/0xbe0 kernel/time/timer.c:1817 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 run_ksoftirqd+0x1f/0x30 kernel/softirq.c:603 smpboot_thread_fn+0x545/0x930 kernel/smpboot.c:165 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Modules linked in: CR2: 0000000000000000 ---[ end trace c466585b3d02cd59 ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5ddfb58 EFLAGS: 00010206 RAX: ffffffff8154d7aa RBX: 0000000000000100 RCX: ffff8881f5dc8000 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881da22b1c0 RBP: ffff8881f5ddfd08 R08: ffffffff8154d3ee R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffe578 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881da22b1c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ed683000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 ---------------- Code disassembly (best guess): 0: 03 40 0f add 0xf(%rax),%eax 3: b6 f6 mov $0xf6,%dh 5: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax c: 01 01 01 f: 48 0f af c6 imul %rsi,%rax 13: f3 48 ab rep stos %rax,%es:(%rdi) 16: 89 d1 mov %edx,%ecx 18: f3 aa rep stos %al,%es:(%rdi) 1a: 4c 89 c8 mov %r9,%rax 1d: c3 ret 1e: 90 nop 1f: 49 89 f9 mov %rdi,%r9 22: 40 88 f0 mov %sil,%al 25: 48 89 d1 mov %rdx,%rcx 28: f3 aa rep stos %al,%es:(%rdi) * 2a: 4c 89 c8 mov %r9,%rax <-- trapping instruction 2d: c3 ret 2e: 90 nop 2f: 49 89 fa mov %rdi,%r10 32: 40 0f b6 ce movzbl %sil,%ecx 36: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax 3d: 01 01 01