CVE-2025-38106: In the Linux kernel, the following vulnerability has been resolved:  io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()  syzbot reports:  BUG: KASAN: slab-use-after-free in getrusage+0x1109/0x1a60 Read of size 8 at addr ffff88810de2d2c8 by task a.out/304  CPU: 0 UID: 0 PID: 304 Comm: a.out Not tainted 6.16.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace:  <TASK>  dump_stack_lvl+0x53/0x70  print_report+0xd0/0x670  ? __pfx__raw_spin_lock_irqsave+0x10/0x10  ? getrusage+0x1109/0x1a60  kasan_report+0xce/0x100  ? getrusage+0x1109/0x1a60  getrusage+0x1109/0x1a60  ? __pfx_getrusage+0x10/0x10  __io_uring_show_fdinfo+0x9fe/0x1790  ? ksys_read+0xf7/0x1c0  ? do_syscall_64+0xa4/0x260  ? vsnprintf+0x591/0x1100  ? __pfx___io_uring_show_fdinfo+0x10/0x10  ? __pfx_vsnprintf+0x10/0x10  ? mutex_trylock+0xcf/0x130  ? __pfx_mutex_trylock+0x10/0x10  ? __pfx_show_fd_locks+0x10/0x10  ? io_uring_show_fdinfo+0x57/0x80  io_uring_show_fdinfo+0x57/0x80  seq_show+0x38c/0x690  seq_read_iter+0x3f7/0x1180  ? inode_set_ctime_current+0x160/0x4b0  seq_read+0x271/0x3e0  ? __pfx_seq_read+0x10/0x10  ? __pfx__raw_spin_lock+0x10/0x10  ? __mark_inode_dirty+0x402/0x810  ? selinux_file_permission+0x368/0x500  ? file_update_time+0x10f/0x160  vfs_read+0x177/0xa40  ? __pfx___handle_mm_fault+0x10/0x10  ? __pfx_vfs_read+0x10/0x10  ? mutex_lock+0x81/0xe0  ? __pfx_mutex_lock+0x10/0x10  ? fdget_pos+0x24d/0x4b0  ksys_read+0xf7/0x1c0  ? __pfx_ksys_read+0x10/0x10  ? do_user_addr_fault+0x43b/0x9c0  do_syscall_64+0xa4/0x260  entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0f74170fc9 Code: 00 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 8b 8 RSP: 002b:00007fffece049e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0f74170fc9 RDX: 0000000000001000 RSI: 00007fffece049f0 RDI: 0000000000000004 RBP: 00007fffece05ad0 R08: 0000000000000000 R09: 00007fffece04d90 R10: 0000000000000000 R11: 0000000000000206 R12: 00005651720a1100 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000  </TASK>  Allocated by task 298:  kasan_save_stack+0x33/0x60  kasan_save_track+0x14/0x30  __kasan_slab_alloc+0x6e/0x70  kmem_cache_alloc_node_noprof+0xe8/0x330  copy_process+0x376/0x5e00  create_io_thread+0xab/0xf0  io_sq_offload_create+0x9ed/0xf20  io_uring_setup+0x12b0/0x1cc0  do_syscall_64+0xa4/0x260  entry_SYSCALL_64_after_hwframe+0x77/0x7f  Freed by task 22:  kasan_save_stack+0x33/0x60  kasan_save_track+0x14/0x30  kasan_save_free_info+0x3b/0x60  __kasan_slab_free+0x37/0x50  kmem_cache_free+0xc4/0x360  rcu_core+0x5ff/0x19f0  handle_softirqs+0x18c/0x530  run_ksoftirqd+0x20/0x30  smpboot_thread_fn+0x287/0x6c0  kthread+0x30d/0x630  ret_from_fork+0xef/0x1a0  ret_from_fork_asm+0x1a/0x30  Last potentially related work creation:  kasan_save_stack+0x33/0x60  kasan_record_aux_stack+0x8c/0xa0  __call_rcu_common.constprop.0+0x68/0x940  __schedule+0xff2/0x2930  __cond_resched+0x4c/0x80  mutex_lock+0x5c/0xe0  io_uring_del_tctx_node+0xe1/0x2b0  io_uring_clean_tctx+0xb7/0x160  io_uring_cancel_generic+0x34e/0x760  do_exit+0x240/0x2350  do_group_exit+0xab/0x220  __x64_sys_exit_group+0x39/0x40  x64_sys_call+0x1243/0x1840  do_syscall_64+0xa4/0x260  entry_SYSCALL_64_after_hwframe+0x77/0x7f  The buggy address belongs to the object at ffff88810de2cb00  which belongs to the cache task_struct of size 3712 The buggy address is located 1992 bytes inside of  freed 3712-byte region [ffff88810de2cb00, ffff88810de2d980)  which is caused by the task_struct pointed to by sq->thread being released while it is being used in the function __io_uring_show_fdinfo(). Holding ctx->uring_lock does not prevent ehre relase or exit of sq->thread.  Fix this by assigning and looking up ->thread under RCU, and grabbing a reference to the task_struct. This e ---truncated---