================================================================== BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline] BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline] BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1482 [inline] BUG: KASAN: use-after-free in __run_timers+0x7be/0xbe0 kernel/time/timer.c:1817 Write of size 8 at addr ffff8881d2d031c8 by task syz-executor.2/1008 CPU: 0 PID: 1008 Comm: syz-executor.2 Tainted: G W 5.4.274-syzkaller-00016-gdd432c37afcd #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_del include/linux/list.h:791 [inline] detach_timer kernel/time/timer.c:824 [inline] expire_timers kernel/time/timer.c:1482 [inline] __run_timers+0x7be/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:do_check+0x661e/0x9820 kernel/bpf/verifier.c:8097 Code: 31 ff 89 c6 e8 73 78 f3 ff 85 db 0f 85 53 2e 00 00 e8 76 75 f3 ff 48 8b 5c 24 50 48 8b 44 24 78 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 44 5a 23 00 4c 8b 33 4d 85 f6 0f 84 RSP: 0018:ffff8881d317f0a0 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff13 RAX: 1ffff1103a5a0805 RBX: ffff8881d2d04028 RCX: dffffc0000000000 RDX: ffffc90001f4d000 RSI: 0000000000032a43 RDI: 0000000000032a44 RBP: ffff8881d317f330 R08: ffffffff817093a9 R09: ffffffff846031dc R10: ffffffff84800000 R11: dffffc0000000000 R12: dffffc0000000000 R13: 0000000000000040 R14: ffff8881d2ccc498 R15: 0000000000001bf8 bpf_check+0x2169/0xb340 kernel/bpf/verifier.c:9637 bpf_prog_load kernel/bpf/syscall.c:1724 [inline] __do_sys_bpf kernel/bpf/syscall.c:2891 [inline] __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7fb8faeb5f69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb8fa2300c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fb8fafecf80 RCX: 00007fb8faeb5f69 RDX: 0000000000000048 RSI: 0000000020000200 RDI: 0000000000000005 RBP: 00007fb8faf136fe R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fb8fafecf80 R15: 00007ffd9c2c6a58 Allocated by task 376: 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 kmem_cache_zalloc include/linux/slab.h:680 [inline] copy_signal+0x51/0x5d0 kernel/fork.c:1572 copy_process+0x1265/0x3230 kernel/fork.c:2049 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone kernel/fork.c:2557 [inline] __se_sys_clone kernel/fork.c:2538 [inline] __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 124: 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 free_signal_struct kernel/fork.c:732 [inline] put_signal_struct kernel/fork.c:738 [inline] __put_task_struct+0x280/0x410 kernel/fork.c:752 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 The buggy address belongs to the object at ffff8881d2d02f80 which belongs to the cache signal_cache of size 1088 The buggy address is located 584 bytes inside of 1088-byte region [ffff8881d2d02f80, ffff8881d2d033c0) The buggy address belongs to the page: page:ffffea00074b4000 refcount:1 mapcount:0 mapping:ffff8881f5cf8500 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cf8500 raw: 0000000000000000 00000000800d000d 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, 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 kmem_cache_zalloc include/linux/slab.h:680 [inline] copy_signal+0x51/0x5d0 kernel/fork.c:1572 copy_process+0x1265/0x3230 kernel/fork.c:2049 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone kernel/fork.c:2557 [inline] __se_sys_clone kernel/fork.c:2538 [inline] __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538 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 bpf_check+0x8aaa/0xb340 kernel/bpf/verifier.c:9731 bpf_prog_load kernel/bpf/syscall.c:1724 [inline] __do_sys_bpf kernel/bpf/syscall.c:2891 [inline] __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881d2d03080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d2d03100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881d2d03180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ---------------- Code disassembly (best guess): 0: 31 ff xor %edi,%edi 2: 89 c6 mov %eax,%esi 4: e8 73 78 f3 ff call 0xfff3787c 9: 85 db test %ebx,%ebx b: 0f 85 53 2e 00 00 jne 0x2e64 11: e8 76 75 f3 ff call 0xfff3758c 16: 48 8b 5c 24 50 mov 0x50(%rsp),%rbx 1b: 48 8b 44 24 78 mov 0x78(%rsp),%rax 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 27: fc ff df * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 48 89 df mov %rbx,%rdi 33: e8 44 5a 23 00 call 0x235a7c 38: 4c 8b 33 mov (%rbx),%r14 3b: 4d 85 f6 test %r14,%r14 3e: 0f .byte 0xf 3f: 84 .byte 0x84