================================================================== 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 ffff8881dcba31c8 by task syz-executor.2/1914 CPU: 1 PID: 1914 Comm: syz-executor.2 Not tainted 5.4.276-syzkaller-04917-g58de09405d1e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 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:539 [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+0x4/0x40 mm/kasan/common.c:105 Code: e8 09 00 00 c3 90 89 f6 48 8b 0c 24 31 d2 e9 93 22 00 00 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 80 22 00 00 55 41 56 53 <48> 89 d3 41 89 f6 48 89 fd 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 RSP: 0018:ffff8881e249f120 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff8881e249f475 RBX: ffff8881e249f478 RCX: 1ffff1103c493e88 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff8881e249f490 RBP: ffff8881e249f430 R08: 0000000000000001 R09: ffff8881e249f490 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0c37ded R13: ffffffff861bef68 R14: ffff8881e249f440 R15: dffffc0000000000 unwind_next_frame+0x1036/0x1ea0 arch/x86/kernel/unwind_orc.c:534 arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123 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] __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449 kstrdup mm/util.c:60 [inline] kstrdup_const+0x51/0x90 mm/util.c:82 alloc_vfsmnt+0x97/0x440 fs/namespace.c:186 clone_mnt+0x6c/0xbc0 fs/namespace.c:1023 copy_tree+0x408/0xb50 fs/namespace.c:1802 copy_mnt_ns+0x12c/0x960 fs/namespace.c:3261 create_new_namespaces+0xd6/0x570 kernel/nsproxy.c:71 copy_namespaces+0x169/0x1b0 kernel/nsproxy.c:161 copy_process+0x12da/0x3230 kernel/fork.c:2055 _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 RIP: 0033:0x7fe41070da29 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe410693078 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fe41081ff80 RCX: 00007fe41070da29 RDX: 0000000000000000 RSI: 0000000000002ae0 RDI: 0000000096020007 RBP: 00007fe4107692d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 000000000000000b R14: 00007fe41081ff80 R15: 00007ffe083a1808 Allocated by task 678: 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 shmem_alloc_inode+0x16/0x30 mm/shmem.c:3719 alloc_inode fs/inode.c:231 [inline] new_inode_pseudo+0x60/0x210 fs/inode.c:927 new_inode+0x25/0x1d0 fs/inode.c:956 shmem_get_inode+0x10b/0x620 mm/shmem.c:2252 shmem_mknod+0x54/0x1a0 mm/shmem.c:2844 lookup_open fs/namei.c:3379 [inline] do_last fs/namei.c:3471 [inline] path_openat+0x184a/0x34b0 fs/namei.c:3683 do_filp_open+0x20b/0x450 fs/namei.c:3713 do_sys_open+0x39c/0x810 fs/open.c:1123 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 17: 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 __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 ffff8881dcba3090 which belongs to the cache shmem_inode_cache of size 760 The buggy address is located 312 bytes inside of 760-byte region [ffff8881dcba3090, ffff8881dcba3388) The buggy address belongs to the page: page:ffffea000772e800 refcount:1 mapcount:0 mapping:ffff8881f5d06780 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d06780 raw: 0000000000000000 0000000000120012 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 shmem_alloc_inode+0x16/0x30 mm/shmem.c:3719 alloc_inode fs/inode.c:231 [inline] new_inode_pseudo+0x60/0x210 fs/inode.c:927 new_inode+0x25/0x1d0 fs/inode.c:956 shmem_get_inode+0x10b/0x620 mm/shmem.c:2252 shmem_mknod+0x54/0x1a0 mm/shmem.c:2844 lookup_open fs/namei.c:3379 [inline] do_last fs/namei.c:3471 [inline] path_openat+0x184a/0x34b0 fs/namei.c:3683 do_filp_open+0x20b/0x450 fs/namei.c:3713 do_sys_open+0x39c/0x810 fs/open.c:1123 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 tun_set_iff+0x870/0xdc0 drivers/net/tun.c:2921 __tun_chr_ioctl+0x8a9/0x1d00 drivers/net/tun.c:3184 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881dcba3080: fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881dcba3100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881dcba3180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881dcba3200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881dcba3280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 1d909f067 P4D 1d909f067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1914 Comm: syz-executor.2 Tainted: G B 5.4.276-syzkaller-04917-g58de09405d1e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010002 RAX: ffffffff8154d48a RBX: 0000000000000101 RCX: ffff8881ed141f80 RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881dcba31c0 RBP: ffff8881f6f09ec8 R08: ffffffff8154d0ce R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa4a0 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881dcba31c0 FS: 00007fe4106936c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ec825000 CR4: 00000000003406a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: call_timer_fn+0x36/0x390 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1488 [inline] __run_timers+0x8a5/0xbe0 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:539 [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+0x4/0x40 mm/kasan/common.c:105 Code: e8 09 00 00 c3 90 89 f6 48 8b 0c 24 31 d2 e9 93 22 00 00 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 80 22 00 00 55 41 56 53 <48> 89 d3 41 89 f6 48 89 fd 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 RSP: 0018:ffff8881e249f120 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff8881e249f475 RBX: ffff8881e249f478 RCX: 1ffff1103c493e88 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff8881e249f490 RBP: ffff8881e249f430 R08: 0000000000000001 R09: ffff8881e249f490 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0c37ded R13: ffffffff861bef68 R14: ffff8881e249f440 R15: dffffc0000000000 unwind_next_frame+0x1036/0x1ea0 arch/x86/kernel/unwind_orc.c:534 arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123 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] __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449 kstrdup mm/util.c:60 [inline] kstrdup_const+0x51/0x90 mm/util.c:82 alloc_vfsmnt+0x97/0x440 fs/namespace.c:186 clone_mnt+0x6c/0xbc0 fs/namespace.c:1023 copy_tree+0x408/0xb50 fs/namespace.c:1802 copy_mnt_ns+0x12c/0x960 fs/namespace.c:3261 create_new_namespaces+0xd6/0x570 kernel/nsproxy.c:71 copy_namespaces+0x169/0x1b0 kernel/nsproxy.c:161 copy_process+0x12da/0x3230 kernel/fork.c:2055 _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 RIP: 0033:0x7fe41070da29 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe410693078 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fe41081ff80 RCX: 00007fe41070da29 RDX: 0000000000000000 RSI: 0000000000002ae0 RDI: 0000000096020007 RBP: 00007fe4107692d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 000000000000000b R14: 00007fe41081ff80 R15: 00007ffe083a1808 Modules linked in: CR2: 0000000000000000 ---[ end trace a7f47374f730c96b ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010002 RAX: ffffffff8154d48a RBX: 0000000000000101 RCX: ffff8881ed141f80 RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881dcba31c0 RBP: ffff8881f6f09ec8 R08: ffffffff8154d0ce R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa4a0 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881dcba31c0 FS: 00007fe4106936c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ec825000 CR4: 00000000003406a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: e8 09 00 00 c3 call 0xc300000e 5: 90 nop 6: 89 f6 mov %esi,%esi 8: 48 8b 0c 24 mov (%rsp),%rcx c: 31 d2 xor %edx,%edx e: e9 93 22 00 00 jmp 0x22a6 13: 0f 1f 00 nopl (%rax) 16: 89 f6 mov %esi,%esi 18: 48 8b 0c 24 mov (%rsp),%rcx 1c: ba 01 00 00 00 mov $0x1,%edx 21: e9 80 22 00 00 jmp 0x22a6 26: 55 push %rbp 27: 41 56 push %r14 29: 53 push %rbx * 2a: 48 89 d3 mov %rdx,%rbx <-- trapping instruction 2d: 41 89 f6 mov %esi,%r14d 30: 48 89 fd mov %rdi,%rbp 33: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx 38: 48 89 d6 mov %rdx,%rsi 3b: ba 01 00 00 00 mov $0x1,%edx