================================================================== BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x105/0x130 lib/list_debug.c:29 Read of size 8 at addr ffff8880269b7940 by task syz.2.15171/7558 CPU: 1 UID: 0 PID: 7558 Comm: syz.2.15171 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+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 __list_add_valid_or_report+0x105/0x130 lib/list_debug.c:29 __list_add_valid include/linux/list.h:96 [inline] __list_add include/linux/list.h:158 [inline] list_add include/linux/list.h:177 [inline] clone_mnt+0x633/0x930 fs/namespace.c:1275 copy_tree+0xfc/0xbf0 fs/namespace.c:2159 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x455/0xab0 kernel/fork.c:3174 __do_sys_unshare kernel/fork.c:3245 [inline] __se_sys_unshare kernel/fork.c:3243 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f221e59c629 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f221f48d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f221e815fa0 RCX: 00007f221e59c629 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000002a020400 RBP: 00007f221e632b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f221e816038 R14: 00007f221e815fa0 R15: 00007ffc0e08d128 Allocated by task 5885: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4501 [inline] slab_alloc_node mm/slub.c:4830 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4837 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287 clone_mnt+0x4b/0x930 fs/namespace.c:1246 create_new_namespace fs/namespace.c:3098 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0xb02/0x1500 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0xa3/0x150 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 33: 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:2687 [inline] slab_free mm/slub.c:6124 [inline] kmem_cache_free+0x124/0x6a0 mm/slub.c:6254 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1063 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to last potentially related work creation: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 task_work_add+0x28b/0x3b0 kernel/task_work.c:70 mntput_no_expire_slowpath+0x3da/0xb00 fs/namespace.c:1379 mntput_no_expire+0x1fd/0x220 fs/namespace.c:1406 mntput+0x6b/0xa0 fs/namespace.c:1416 create_new_namespace fs/namespace.c:3082 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0x1235/0x1500 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0xa3/0x150 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880269b7880 which belongs to the cache mnt_cache of size 352 The buggy address is located 192 bytes inside of freed 352-byte region [ffff8880269b7880, ffff8880269b79e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x269b6 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888058697001 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801ceb4280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800120012 00000000f5000000 ffff888058697001 head: 00fff00000000040 ffff88801ceb4280 dead000000000100 dead000000000122 head: 0000000000000000 0000000800120012 00000000f5000000 ffff888058697001 head: 00fff00000000001 ffffea00009a6d81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 6870427730, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab mm/slub.c:3444 [inline] new_slab+0xa6/0x6d0 mm/slub.c:3502 refill_objects+0x26b/0x400 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] alloc_full_sheaf mm/slub.c:2825 [inline] __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] kmem_cache_alloc_noprof+0x480/0x6e0 mm/slub.c:4837 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287 vfs_create_mount fs/namespace.c:1178 [inline] vfs_create_mount fs/namespace.c:1171 [inline] fc_mount fs/namespace.c:1196 [inline] fc_mount+0x105/0x220 fs/namespace.c:1191 vfs_kern_mount.part.0+0x10e/0x120 fs/namespace.c:1231 vfs_kern_mount+0x3f/0x60 fs/namespace.c:1219 simple_pin_fs+0xf2/0x190 fs/libfs.c:1103 drm_fs_inode_new drivers/gpu/drm/drm_drv.c:640 [inline] drm_dev_init+0x465/0x980 drivers/gpu/drm/drm_drv.c:749 devm_drm_dev_init drivers/gpu/drm/drm_drv.c:809 [inline] __devm_drm_dev_alloc+0x4c/0xf0 drivers/gpu/drm/drm_drv.c:830 vgem_init+0xc5/0x170 drivers/gpu/drm/vgem/vgem_drv.c:144 do_one_initcall+0x11d/0x760 init/main.c:1382 page_owner free stack trace missing Memory state around the buggy address: ffff8880269b7800: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff8880269b7880: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880269b7900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880269b7980: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880269b7a00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ==================================================================