================================================================== BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166 Read of size 1 at addr ffff8880259e5818 by task syz.0.2178/14643 CPU: 0 UID: 0 PID: 14643 Comm: syz.0.2178 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595 __kasan_check_byte+0x36/0x50 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire kernel/locking/lockdep.c:5842 [inline] lock_acquire+0x12a/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166 p9_tag_remove net/9p/client.c:274 [inline] p9_req_put net/9p/client.c:282 [inline] p9_req_put+0xaf/0x250 net/9p/client.c:279 req_done+0x1dc/0x2e0 net/9p/trans_virtio.c:147 vring_interrupt+0x2ef/0x650 drivers/virtio/virtio_ring.c:3254 __handle_irq_event_percpu+0x235/0x8c0 kernel/irq/handle.c:209 handle_irq_event_percpu kernel/irq/handle.c:246 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:263 handle_edge_irq+0x35e/0x960 kernel/irq/chip.c:856 generic_handle_irq_desc include/linux/irqdesc.h:186 [inline] handle_irq arch/x86/kernel/irq.c:262 [inline] call_irq_handler arch/x86/kernel/irq.c:318 [inline] __common_interrupt+0xd8/0x2f0 arch/x86/kernel/irq.c:333 common_interrupt+0xb9/0xe0 arch/x86/kernel/irq.c:326 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 06 cb 58 f6 48 89 df e8 de 1a 59 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 75 e4 48 f6 65 8b 05 1e 7f 7f 08 85 c0 74 16 5b RSP: 0018:ffffc90006a3fb50 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff88801cb52f70 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df1e748 RDI: ffffffff8c1c3a00 RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff88801cb52500 R13: ffff88801cb52f70 R14: ffffffff940c7380 R15: ffffc90006a3fbb0 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] try_to_wake_up+0x5ec/0x1900 kernel/sched/core.c:4190 wake_up_process kernel/sched/core.c:4434 [inline] wake_up_q+0xa1/0x130 kernel/sched/core.c:1158 futex_wake+0x460/0x530 kernel/futex/waitwake.c:198 do_futex+0x32b/0x350 kernel/futex/syscalls.c:135 __do_sys_futex_time32 kernel/futex/syscalls.c:523 [inline] __se_sys_futex_time32 kernel/futex/syscalls.c:506 [inline] __ia32_sys_futex_time32+0x2f4/0x470 kernel/futex/syscalls.c:506 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fd4fcc Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8 RSP: 002b:00000000ffd5dd1c EFLAGS: 00000246 ORIG_RAX: 00000000000000f0 RAX: ffffffffffffffda RBX: 00000000f7494f88 RCX: 0000000000000081 RDX: 00000000000f4240 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 14644: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:950 [inline] p9_client_create+0xaf/0xd40 net/9p/client.c:862 v9fs_session_init+0x3c/0xd20 fs/9p/v9fs.c:446 v9fs_get_tree+0xb8/0xb50 fs/9p/vfs_super.c:97 vfs_get_tree+0x92/0x320 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount fs/namespace.c:3834 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4154 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount fs/namespace.c:4360 [inline] __ia32_sys_mount+0x292/0x310 fs/namespace.c:4360 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 14644: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6250 [inline] kfree+0x223/0x6c0 mm/slub.c:6565 p9_client_create+0x72d/0xd40 net/9p/client.c:941 v9fs_session_init+0x3c/0xd20 fs/9p/v9fs.c:446 v9fs_get_tree+0xb8/0xb50 fs/9p/vfs_super.c:97 vfs_get_tree+0x92/0x320 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount fs/namespace.c:3834 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4154 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount fs/namespace.c:4360 [inline] __ia32_sys_mount+0x292/0x310 fs/namespace.c:4360 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff8880259e5800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of freed 512-byte region [ffff8880259e5800, ffff8880259e5a00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x259e4 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b842c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5746, tgid 5746 (syz-executor), ts 70452932770, free_ts 67431766306 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7271 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __do_kmalloc_node mm/slub.c:5294 [inline] __kmalloc_noprof+0x688/0x850 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3828 ip6_route_add+0x4b/0x1d0 net/ipv6/route.c:3957 addrconf_prefix_route+0x2fb/0x510 net/ipv6/addrconf.c:2488 inet6_addr_add+0x575/0x9a0 net/ipv6/addrconf.c:3053 inet6_rtm_newaddr+0x1475/0x1bb0 net/ipv6/addrconf.c:5071 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6996 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344 page last free pid 23 tgid 23 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2943 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1076 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880259e5700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880259e5780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880259e5800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880259e5880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880259e5900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: f5 cmc 1: 53 push %rbx 2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi 7: 48 89 fb mov %rdi,%rbx a: 48 83 c7 18 add $0x18,%rdi e: e8 06 cb 58 f6 call 0xf658cb19 13: 48 89 df mov %rbx,%rdi 16: e8 de 1a 59 f6 call 0xf6591af9 1b: f7 c5 00 02 00 00 test $0x200,%ebp 21: 75 23 jne 0x46 23: 9c pushf 24: 58 pop %rax 25: f6 c4 02 test $0x2,%ah 28: 75 37 jne 0x61 * 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction 2f: e8 75 e4 48 f6 call 0xf648e4a9 34: 65 8b 05 1e 7f 7f 08 mov %gs:0x87f7f1e(%rip),%eax # 0x87f7f59 3b: 85 c0 test %eax,%eax 3d: 74 16 je 0x55 3f: 5b pop %rbx