================================================================== BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x271/0x2c0 kernel/locking/spinlock_debug.c:115 Read of size 4 at addr ffff88801192f804 by task syz.3.2264/13242 CPU: 0 UID: 0 PID: 13242 Comm: syz.3.2264 Not tainted 6.13.0-rc4-syzkaller-00078-g059dd502b263 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xc3/0x620 mm/kasan/report.c:489 kasan_report+0xd9/0x110 mm/kasan/report.c:602 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] do_raw_spin_lock+0x271/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162 p9_tag_remove net/9p/client.c:397 [inline] p9_req_put net/9p/client.c:405 [inline] p9_req_put+0xaf/0x250 net/9p/client.c:402 req_done+0x1e7/0x2f0 net/9p/trans_virtio.c:147 vring_interrupt drivers/virtio/virtio_ring.c:2715 [inline] vring_interrupt+0x31b/0x400 drivers/virtio/virtio_ring.c:2690 __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285 common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 e6 91 59 f6 48 89 df e8 1e 11 5a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 45 01 4b f6 65 8b 05 b6 24 e7 74 85 c0 74 16 5b RSP: 0018:ffffc90026a7fb78 EFLAGS: 00000246 RAX: 0000000000000046 RBX: ffff888022512e40 RCX: 1ffffffff203a2fa RDX: 0000000000000000 RSI: ffffffff8bb16fc0 RDI: ffffffff8b1cb5a2 RBP: 0000000000000202 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff901ce4d7 R11: 0000000000000000 R12: ffff888022512454 R13: ffff888022512e40 R14: ffff888022512440 R15: ffffc90026a7fbd8 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0x949/0x1490 kernel/sched/core.c:4205 wake_up_process kernel/sched/core.c:4454 [inline] wake_up_q+0x91/0x140 kernel/sched/core.c:1066 futex_wake+0x43e/0x4e0 kernel/futex/waitwake.c:199 do_futex+0x1e5/0x350 kernel/futex/syscalls.c:107 __do_sys_futex_time32 kernel/futex/syscalls.c:509 [inline] __se_sys_futex_time32 kernel/futex/syscalls.c:492 [inline] __ia32_sys_futex_time32+0x1da/0x460 kernel/futex/syscalls.c:492 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f82579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000ffe36d5c EFLAGS: 00000246 ORIG_RAX: 00000000000000f0 RAX: ffffffffffffffda RBX: 00000000f7445018 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 13244: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:901 [inline] p9_client_create+0xc8/0x11a0 net/9p/client.c:985 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410 v9fs_mount+0xc6/0xa30 fs/9p/vfs_super.c:122 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1814 do_new_mount fs/namespace.c:3507 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3834 do_mount fs/namespace.c:3847 [inline] __do_sys_mount fs/namespace.c:4057 [inline] __se_sys_mount fs/namespace.c:4034 [inline] __ia32_sys_mount+0x292/0x310 fs/namespace.c:4034 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 13244: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x14f/0x4b0 mm/slub.c:4761 p9_client_create+0x97d/0x11a0 net/9p/client.c:1064 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410 v9fs_mount+0xc6/0xa30 fs/9p/vfs_super.c:122 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1814 do_new_mount fs/namespace.c:3507 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3834 do_mount fs/namespace.c:3847 [inline] __do_sys_mount fs/namespace.c:4057 [inline] __se_sys_mount fs/namespace.c:4034 [inline] __ia32_sys_mount+0x292/0x310 fs/namespace.c:4034 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff88801192f800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 4 bytes inside of freed 512-byte region [ffff88801192f800, ffff88801192fa00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801192d400 pfn:0x1192c head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801ac42c80 0000000000000000 dead000000000001 raw: ffff88801192d400 000000008010000c 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801ac42c80 0000000000000000 dead000000000001 head: ffff88801192d400 000000008010000c 00000001f5000000 0000000000000000 head: 00fff00000000002 ffffea0000464b01 ffffffffffffffff 0000000000000000 head: ffff888000000004 0000000000000000 00000000ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 13196, tgid 13194 (syz.1.2251), ts 537556333824, free_ts 536771897979 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1558 prep_new_page mm/page_alloc.c:1566 [inline] get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3476 __alloc_pages_noprof+0x223/0x25b0 mm/page_alloc.c:4753 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2269 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab mm/slub.c:2589 [inline] new_slab+0x2c9/0x410 mm/slub.c:2642 ___slab_alloc+0xce2/0x1650 mm/slub.c:3830 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920 __slab_alloc_node mm/slub.c:3995 [inline] slab_alloc_node mm/slub.c:4156 [inline] __kmalloc_cache_noprof+0xf6/0x420 mm/slub.c:4324 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] sctp_endpoint_new+0x7c/0xc90 net/sctp/endpointola.c:134 sctp_init_sock+0xe2c/0x1330 net/sctp/socket.c:5077 sctp_v6_init_sock+0x16/0x70 net/sctp/socket.c:9725 inet6_create net/ipv6/af_inet6.c:259 [inline] inet6_create+0xb53/0x1320 net/ipv6/af_inet6.c:120 __sock_create+0x335/0x8d0 net/socket.c:1558 sock_create net/socket.c:1616 [inline] __sys_socket_create net/socket.c:1653 [inline] __sys_socket+0x14f/0x260 net/socket.c:1700 __do_sys_socket net/socket.c:1714 [inline] __se_sys_socket net/socket.c:1712 [inline] __ia32_sys_socket+0x72/0xb0 net/socket.c:1712 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 page last free pid 13191 tgid 13190 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_unref_page+0x661/0x1080 mm/page_alloc.c:2659 __put_partials+0x14c/0x170 mm/slub.c:3157 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4119 [inline] slab_alloc_node mm/slub.c:4168 [inline] kmem_cache_alloc_node_noprof+0x1ca/0x3b0 mm/slub.c:4220 __alloc_skb+0x2b3/0x380 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1323 [inline] alloc_skb_with_frags+0xe4/0x850 net/core/skbuff.c:6612 sock_alloc_send_pskb+0x7f1/0x980 net/core/sock.c:2881 unix_dgram_sendmsg+0x46c/0x1940 net/unix/af_unix.c:2027 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2583 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637 __sys_sendmmsg+0x2fa/0x420 net/socket.c:2719 __compat_sys_sendmmsg net/compat.c:360 [inline] __do_compat_sys_sendmmsg net/compat.c:367 [inline] __se_compat_sys_sendmmsg net/compat.c:364 [inline] __ia32_compat_sys_sendmmsg+0x9d/0x100 net/compat.c:364 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 Memory state around the buggy address: ffff88801192f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88801192f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801192f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801192f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801192f900: 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 e6 91 59 f6 call 0xf65991f9 13: 48 89 df mov %rbx,%rdi 16: e8 1e 11 5a f6 call 0xf65a1139 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 45 01 4b f6 call 0xf64b0179 34: 65 8b 05 b6 24 e7 74 mov %gs:0x74e724b6(%rip),%eax # 0x74e724f1 3b: 85 c0 test %eax,%eax 3d: 74 16 je 0x55 3f: 5b pop %rbx