================================================================== BUG: KASAN: slab-use-after-free in kernfs_test_super+0x122/0x150 fs/kernfs/mount.c:286 Read of size 8 at addr ffff888025868888 by task syz-executor.1/9336 CPU: 2 PID: 9336 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-01207-g1c59d383390f #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc4/0x620 mm/kasan/report.c:475 kasan_report+0xda/0x110 mm/kasan/report.c:588 kernfs_test_super+0x122/0x150 fs/kernfs/mount.c:286 sget_fc+0x582/0x9b0 fs/super.c:778 kernfs_get_tree+0x198/0x990 fs/kernfs/mount.c:337 sysfs_get_tree+0x41/0x140 fs/sysfs/mount.c:31 vfs_get_tree+0x8c/0x370 fs/super.c:1711 do_new_mount fs/namespace.c:3335 [inline] path_mount+0x1492/0x1ed0 fs/namespace.c:3662 do_mount fs/namespace.c:3675 [inline] __do_sys_mount fs/namespace.c:3884 [inline] __se_sys_mount fs/namespace.c:3861 [inline] __ia32_sys_mount+0x291/0x310 fs/namespace.c:3861 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f8c579 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:00000000f7f875ac EFLAGS: 00000292 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000020000140 RDX: 0000000020000640 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 9332: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:582 [inline] kzalloc include/linux/slab.h:703 [inline] kernfs_get_tree+0x78/0x990 fs/kernfs/mount.c:328 sysfs_get_tree+0x41/0x140 fs/sysfs/mount.c:31 vfs_get_tree+0x8c/0x370 fs/super.c:1711 do_new_mount fs/namespace.c:3335 [inline] path_mount+0x1492/0x1ed0 fs/namespace.c:3662 do_mount fs/namespace.c:3675 [inline] __do_sys_mount fs/namespace.c:3884 [inline] __se_sys_mount fs/namespace.c:3861 [inline] __ia32_sys_mount+0x291/0x310 fs/namespace.c:3861 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Freed by task 5180: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x15e/0x1b0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1792 [inline] slab_free_freelist_hook+0x10b/0x1e0 mm/slub.c:1818 slab_free mm/slub.c:3801 [inline] __kmem_cache_free+0xb8/0x2f0 mm/slub.c:3814 sysfs_kill_sb+0x21/0x30 fs/sysfs/mount.c:86 deactivate_locked_super+0xa0/0x2d0 fs/super.c:454 deactivate_super+0xde/0x100 fs/super.c:504 cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254 task_work_run+0x14d/0x240 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x60 kernel/entry/common.c:296 __do_fast_syscall_32+0x6d/0xe0 arch/x86/entry/common.c:181 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Last potentially related work creation: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492 kvfree_call_rcu+0x70/0xbe0 kernel/rcu/tree.c:3372 sctp_inet6addr_event+0x424/0x900 net/sctp/ipv6.c:115 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93 atomic_notifier_call_chain+0x73/0x1c0 kernel/notifier.c:231 addrconf_ifdown.isra.0+0xef1/0x1c50 net/ipv6/addrconf.c:3885 addrconf_notify+0x8dc/0x1940 net/ipv6/addrconf.c:3674 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962 netdev_state_change net/core/dev.c:1344 [inline] netdev_state_change+0x111/0x140 net/core/dev.c:1337 do_setlink+0x3237/0x3fa0 net/core/rtnetlink.c:3116 rtnl_group_changelink net/core/rtnetlink.c:3423 [inline] __rtnl_newlink+0xdeb/0x1940 net/core/rtnetlink.c:3682 rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3719 rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6445 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0xd9/0x180 net/socket.c:748 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2494 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2548 __sys_sendmsg+0x117/0x1e0 net/socket.c:2577 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 The buggy address belongs to the object at ffff888025868880 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 8 bytes inside of freed 64-byte region [ffff888025868880, ffff8880258688c0) The buggy address belongs to the physical page: page:ffffea0000961a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25868 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000200 ffff888012842640 ffffea00006b05c0 dead000000000002 raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 4649, tgid 4649 (udevd), ts 148823321324, free_ts 148766890777 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x2d2/0x350 mm/page_alloc.c:1570 prep_new_page mm/page_alloc.c:1577 [inline] get_page_from_freelist+0x10a9/0x31e0 mm/page_alloc.c:3221 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4477 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298 alloc_slab_page mm/slub.c:1862 [inline] allocate_slab+0x24e/0x380 mm/slub.c:2009 new_slab mm/slub.c:2062 [inline] ___slab_alloc+0x8bc/0x1570 mm/slub.c:3215 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3314 __slab_alloc_node mm/slub.c:3367 [inline] slab_alloc_node mm/slub.c:3460 [inline] __kmem_cache_alloc_node+0x137/0x350 mm/slub.c:3509 __do_kmalloc_node mm/slab_common.c:984 [inline] __kmalloc+0x4c/0x100 mm/slab_common.c:998 kmalloc include/linux/slab.h:586 [inline] kzalloc include/linux/slab.h:703 [inline] tomoyo_encode2+0x100/0x3d0 security/tomoyo/realpath.c:45 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x196/0x710 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x2aa/0x3b0 security/tomoyo/file.c:771 tomoyo_file_open security/tomoyo/tomoyo.c:332 [inline] tomoyo_file_open+0xa8/0xd0 security/tomoyo/tomoyo.c:327 security_file_open+0x6a/0xe0 security/security.c:2811 do_dentry_open+0x538/0x1730 fs/open.c:916 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1161 [inline] free_unref_page_prepare+0x508/0xb90 mm/page_alloc.c:2348 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2443 vfree+0x181/0x7a0 mm/vmalloc.c:2842 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:2763 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Memory state around the buggy address: ffff888025868780: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff888025868800: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff888025868880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888025868900: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ffff888025868980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi