================================================================== BUG: KASAN: use-after-free in xas_next_entry include/linux/xarray.h:1630 [inline] BUG: KASAN: use-after-free in __io_uring_files_cancel+0x417/0x440 fs/io_uring.c:8681 Read of size 1 at addr ffff88807545c640 by task syz-executor.1/8917 CPU: 1 PID: 8917 Comm: syz-executor.1 Not tainted 5.9.0-rc8-next-20201008-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fb lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 xas_next_entry include/linux/xarray.h:1630 [inline] __io_uring_files_cancel+0x417/0x440 fs/io_uring.c:8681 io_uring_files_cancel include/linux/io_uring.h:35 [inline] exit_files+0xe4/0x170 fs/file.c:456 do_exit+0xae9/0x2930 kernel/exit.c:801 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de29 Code: Unable to access opcode bytes at RIP 0x45ddff. RSP: 002b:00007fe871746c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffff2 RBX: 0000000000013180 RCX: 000000000045de29 RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000005 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffd1d23b5bf R14: 00007fe8717479c0 R15: 000000000118bf2c Allocated by task 8917: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:514 [inline] slab_alloc mm/slab.c:3314 [inline] kmem_cache_alloc+0x162/0x550 mm/slab.c:3484 xas_alloc+0x330/0x440 lib/xarray.c:374 xas_create+0x2db/0x1020 lib/xarray.c:676 xas_store+0x8a/0x1bb0 lib/xarray.c:784 io_uring_add_task_file fs/io_uring.c:8608 [inline] io_uring_add_task_file+0x212/0x430 fs/io_uring.c:8590 io_uring_get_fd fs/io_uring.c:9116 [inline] io_uring_create fs/io_uring.c:9280 [inline] io_uring_setup+0x2727/0x3660 fs/io_uring.c:9314 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6903: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3420 [inline] kmem_cache_free.part.0+0x74/0x1d0 mm/slab.c:3695 rcu_do_batch kernel/rcu/tree.c:2484 [inline] rcu_core+0x645/0x1240 kernel/rcu/tree.c:2718 __do_softirq+0x203/0xab6 kernel/softirq.c:298 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2960 [inline] call_rcu+0x15e/0x7d0 kernel/rcu/tree.c:3033 xa_node_free lib/xarray.c:258 [inline] xas_delete_node lib/xarray.c:494 [inline] update_node lib/xarray.c:756 [inline] xas_store+0xbcc/0x1bb0 lib/xarray.c:841 io_uring_del_task_file+0x105/0x1a0 fs/io_uring.c:8630 __io_uring_files_cancel+0x3dd/0x440 fs/io_uring.c:8691 io_uring_files_cancel include/linux/io_uring.h:35 [inline] exit_files+0xe4/0x170 fs/file.c:456 do_exit+0xae9/0x2930 kernel/exit.c:801 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2960 [inline] call_rcu+0x15e/0x7d0 kernel/rcu/tree.c:3033 xa_node_free lib/xarray.c:258 [inline] xas_delete_node lib/xarray.c:494 [inline] update_node lib/xarray.c:756 [inline] xas_store+0xbcc/0x1bb0 lib/xarray.c:841 page_cache_delete+0x2de/0x890 mm/filemap.c:138 __delete_from_page_cache mm/filemap.c:239 [inline] delete_from_page_cache+0x15d/0x240 mm/filemap.c:274 truncate_inode_page+0x85/0xd0 mm/truncate.c:228 shmem_undo_range+0x5ef/0x1b00 mm/shmem.c:949 shmem_truncate_range mm/shmem.c:1058 [inline] shmem_evict_inode+0x3a4/0xbc0 mm/shmem.c:1158 evict+0x2ed/0x750 fs/inode.c:578 iput_final fs/inode.c:1654 [inline] iput.part.0+0x3fe/0x820 fs/inode.c:1680 iput+0x58/0x70 fs/inode.c:1670 dentry_unlink_inode+0x2b1/0x3d0 fs/dcache.c:374 __dentry_kill+0x3c0/0x640 fs/dcache.c:579 dentry_kill fs/dcache.c:705 [inline] dput+0x725/0xbc0 fs/dcache.c:878 __fput+0x3ab/0x920 fs/file_table.c:294 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:165 [inline] exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88807545c640 which belongs to the cache radix_tree_node of size 576 The buggy address is located 0 bytes inside of 576-byte region [ffff88807545c640, ffff88807545c880) The buggy address belongs to the page: page:00000000cba5ed85 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807545cffb pfn:0x7545c flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0000cbb888 ffffea0001d51748 ffff88800ec6f000 raw: ffff88807545cffb ffff88807545c0c0 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807545c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807545c580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88807545c600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff88807545c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807545c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================