CVE-2025-40027: In the Linux kernel, the following vulnerability has been resolved:  net/9p: fix double req put in p9_fd_cancelled  Syzkaller reports a KASAN issue as below:  general protection fault, probably for non-canonical address 0xfbd59c0000000021: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdead000000000108-0xdead00000000010f] CPU: 0 PID: 5083 Comm: syz-executor.2 Not tainted 6.1.134-syzkaller-00037-g855bd1d7d838 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:__list_del include/linux/list.h:114 [inline] RIP: 0010:__list_del_entry include/linux/list.h:137 [inline] RIP: 0010:list_del include/linux/list.h:148 [inline] RIP: 0010:p9_fd_cancelled+0xe9/0x200 net/9p/trans_fd.c:734  Call Trace:  <TASK>  p9_client_flush+0x351/0x440 net/9p/client.c:614  p9_client_rpc+0xb6b/0xc70 net/9p/client.c:734  p9_client_version net/9p/client.c:920 [inline]  p9_client_create+0xb51/0x1240 net/9p/client.c:1027  v9fs_session_init+0x1f0/0x18f0 fs/9p/v9fs.c:408  v9fs_mount+0xba/0xcb0 fs/9p/vfs_super.c:126  legacy_get_tree+0x108/0x220 fs/fs_context.c:632  vfs_get_tree+0x8e/0x300 fs/super.c:1573  do_new_mount fs/namespace.c:3056 [inline]  path_mount+0x6a6/0x1e90 fs/namespace.c:3386  do_mount fs/namespace.c:3399 [inline]  __do_sys_mount fs/namespace.c:3607 [inline]  __se_sys_mount fs/namespace.c:3584 [inline]  __x64_sys_mount+0x283/0x300 fs/namespace.c:3584  do_syscall_x64 arch/x86/entry/common.c:51 [inline]  do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81  entry_SYSCALL_64_after_hwframe+0x6e/0xd8  This happens because of a race condition between:  - The 9p client sending an invalid flush request and later cleaning it up; - The 9p client in p9_read_work() canceled all pending requests.        Thread 1                              Thread 2     ...     p9_client_create()     ...     p9_fd_create()     ...     p9_conn_create()     ...     // start Thread 2     INIT_WORK(&m->rq, p9_read_work);                                         p9_read_work()     ...     p9_client_rpc()     ...                                         ...                                         p9_conn_cancel()                                         ...                                         spin_lock(&m->req_lock);     ...     p9_fd_cancelled()     ...                                         ...                                         spin_unlock(&m->req_lock);                                         // status rewrite                                         p9_client_cb(m->client, req, REQ_STATUS_ERROR)                                         // first remove                                         list_del(&req->req_list);                                         ...      spin_lock(&m->req_lock)     ...     // second remove     list_del(&req->req_list);     spin_unlock(&m->req_lock)   ...  Commit 74d6a5d56629 ("9p/trans_fd: Fix concurrency del of req_list in p9_fd_cancelled/p9_read_work") fixes a concurrency issue in the 9p filesystem client where the req_list could be deleted simultaneously by both p9_read_work and p9_fd_cancelled functions, but for the case where req->status equals REQ_STATUS_RCVD.  Update the check for req->status in p9_fd_cancelled to skip processing not just received requests, but anything that is not SENT, as whatever changed the state from SENT also removed the request from its list.  Found by Linux Verification Center (linuxtesting.org) with Syzkaller.  [updated the check from status == RECV || status == ERROR to status != SENT]