kernel/linux.git/fs, branch v7.1.2

virtiofs: fix UAF on submount umount

2026-06-27T10:08:18+00:00

commit 06b41351779e9289e8785694ade9042ae85e41ea upstream. iput() called from fuse_release_end() can Oops if the super block has already been destroyed. Normally this is prevented by waiting for num_waiting to go down to zero before commencing with super block shutdown. This only works, however, for the last submount instance, as the wait counter is per connection, not per superblock. Revert to using synchronous release requests for the auto_submounts case, which is virtiofs only at this time. Reported-by: Aurélien Bombo Reported-by: Zhihao Cheng Cc: Greg Kurz Closes: https://github.com/kata-containers/kata-containers/issues/12589 Fixes: 26e5c67deb2e ("fuse: fix livelock in synchronous file put from fuseblk workers") Cc: stable@vger.kernel.org Reviewed-by: Greg Kurz Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ksmbd: reject non-VALID session in compound request branch

2026-06-27T10:08:17+00:00

commit 609ca17d869d04ba249e32cdcbf13c0b1c66f43c upstream. smb2_check_user_session() takes a shortcut for any operation that is not the first in a COMPOUND request: it reuses work->sess (the session bound by the first operation) and validates only the SessionId, then returns "valid". It never re-checks work->sess->state == SMB2_SESSION_VALID, and a SessionId of 0xFFFFFFFFFFFFFFFF (ULLONG_MAX, the MS-SMB2 related-operation value) skips even the id comparison. The standalone path (ksmbd_session_lookup_all() plus the SESSION_SETUP state machine) does enforce the VALID state; the compound branch bypasses all of it. A SESSION_SETUP carrying only an NTLM Type-1 (NtLmNegotiate) blob publishes a fresh SMB2_SESSION_IN_PROGRESS session whose sess->user is still NULL (->user is assigned later, by ntlm_authenticate()). Used as operation 1 of a COMPOUND with operation 2 = TREE_CONNECT (related, SessionId=ULLONG_MAX, \\host\IPC$), the tree-connect then runs on that IN_PROGRESS session and reaches ksmbd_ipc_tree_connect_request(), which dereferences user_name(sess->user) with sess->user == NULL (transport_ipc.c:687/701/704) -> remote NULL-pointer dereference and a kernel Oops that wedges the ksmbd worker for all clients. Reject any non-first compound operation that lands on a session which is not SMB2_SESSION_VALID, mirroring the validity the standalone lookup path enforces. SESSION_SETUP itself legitimately runs on an IN_PROGRESS session, but it is never carried as a non-first compound operation, so multi-leg authentication is unaffected by this check. Fixes: 5005bcb42191 ("ksmbd: validate session id and tree id in the compound request") Cc: stable@vger.kernel.org Signed-off-by: Gil Portnoy Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

Revert "NFSD: Defer sub-object cleanup in export put callbacks"

2026-06-27T10:08:17+00:00

commit 516403d4d85607fdef3ca41d4a56b54e5566fa9a upstream. This reverts commit 48db892356d6cb80f6942885545de4a6dd8d2a29. Commit 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") moved path_put() and auth_domain_put() out of svc_export_put() and expkey_put() and behind queue_rcu_work() to close a claimed use-after-free in e_show() and c_show() against ex_path and ex_client->name. Discussion in [1] shows neither the diagnosis nor the remedy survives review. The downstream teardown of both sub-objects is already RCU-deferred. auth_domain_put() reaches svcauth_unix_domain_release(), which frees the unix_domain and its ->name through call_rcu(). path_put() reaches dentry_free(), which frees the dentry through call_rcu(), and prepend_path() is already structured to tolerate concurrent dentry teardown. A reader in cache_seq_start_rcu() therefore observes both sub-objects through the next grace period regardless of whether svc_export_put() runs synchronously, so the synchronous form was never unsafe. The crash signature in the report cited by commit 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") has a different root cause: a /proc/net/rpc cache file held open across network-namespace exit lets cache_destroy_net() free cd->hash_table while a reader is still walking it. The correct fix pins cd->net for the open fd's lifetime and does not require any deferral inside svc_export_put(). Meanwhile, deferring path_put() out of svc_export_put() reintroduces the regression that commit 69d803c40ede ("nfsd: Revert "nfsd: release svc_expkey/svc_export with rcu_work"") repaired: after "exportfs -r" drops the last cache reference, the mount reference held through ex_path lingers in the workqueue, so a subsequent umount fails with EBUSY. Restore the synchronous path_put() and auth_domain_put() in svc_export_put() and expkey_put() and the call_rcu()/kfree_rcu() free of the containing structures. The unrelated fix for ex_uuid/ex_stats from commit 2530766492ec ("nfsd: fix UAF when access ex_uuid or ex_stats") is preserved. Link: https://lore.kernel.org/all/10019b42-4589-4f9f-8d5b-d8197db1ce3c@huawei.com/ [1] Fixes: 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Tested-by: Alexandr Alexandrov Signed-off-by: Yang Erkun Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

fuse: re-lock request before replacing page cache folio

2026-06-27T10:08:17+00:00

commit a078484921052d0badd827fcc2770b5cfc1d4120 upstream. fuse_try_move_folio() unlocks the request on entry but does not re-lock it on the success path. This means fuse_chan_abort() can end the request and free the fuse_io_args (eg fuse_readpages_end()) while the subsequent copy chain logic after fuse_try_move_folio() accesses the fuse_io_args, leading to use-after-free issues. Fix this by calling lock_request() before replace_page_cache_folio(). This ensures the request is locked on the success path which will prevent the fuse_io_args from being freed while the later copying logic runs, and also ensures that the ap->folios[i]->mapping is never null since ap->folios[i] will always point to the newfolio after replace_page_cache_folio(). Fixes: ce534fb05292 ("fuse: allow splice to move pages") Cc: stable@vger.kernel.org Reported-by: Lei Lu Signed-off-by: Joanne Koong Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling

2026-06-19T11:50:57+00:00

commit 00633c4683828acd5256fa8d5163f440d74bbe71 upstream. A SOFTIRQ-safe to SOFTIRQ-unsafe lock order deadlock can occur in send_sigio() and send_sigurg() when a process group receives a signal. When FASYNC is configured for a process group (PIDTYPE_PGID), both functions use read_lock(&tasklist_lock) to traverse the task list. However, they are frequently called from softirq context: - send_sigio() via input_inject_event -> kill_fasync - send_sigurg() via tcp_check_urg -> sk_send_sigurg (NET_RX_SOFTIRQ) The deadlock is caused by the rwlock writer fairness mechanism: 1. CPU 0 (process context) holds read_lock(&tasklist_lock) in do_wait(). 2. CPU 1 (process context) attempts write_lock(&tasklist_lock) in fork() or exit() and spins, which blocks all new readers. 3. CPU 0 is interrupted by a softirq (e.g., TCP URG packet reception). 4. The softirq calls send_sigurg() and attempts to acquire read_lock(&tasklist_lock), deadlocking because CPU 1 is waiting. Since PID hashing and do_each_pid_task() traversals are already RCU-protected, the read_lock on tasklist_lock is no longer strictly required for safe traversal. Fix this by replacing tasklist_lock with rcu_read_lock(), aligning the process group signaling path with the single-PID path. This also mitigates a potential remote denial of service vector via TCP URG packets. Lockdep splat: ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected [...] Chain exists of: &dev->event_lock --> &f_owner->lock --> tasklist_lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(tasklist_lock); local_irq_disable(); lock(&dev->event_lock); lock(&f_owner->lock); lock(&dev->event_lock); *** DEADLOCK *** Reviewed-by: Jeff Layton Signed-off-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> Link: https://patch.msgid.link/20260523135210.590928-1-w15303746062@163.com Signed-off-by: Christian Brauner (Amutable) Signed-off-by: Greg Kroah-Hartman

namespace: restrict OPEN_TREE_NAMESPACE/FSMOUNT_NAMESPACE to directories

2026-06-10T14:09:20+00:00

open_tree(..., OPEN_TREE_NAMESPACE) and fsmount(..., FSMOUNT_NAMESPACE, ...) currently work on non-directories, like regular files. That's bad for two reasons: - It ends up mounting a regular file over the inherited namespace root, which is a directory; mounting a non-directory over a directory is normally explicitly forbidden, see for example do_move_mount() - It causes setns() on the new namespace to set the cwd to a regular file, which the rest of VFS does not expect Fix it by restricting create_new_namespace() (which is used by both of these flags) to directories. Leave the behavior for OPEN_TREE_CLONE as-is, that seems unproblematic. Fixes: 9b8a0ba68246 ("mount: add OPEN_TREE_NAMESPACE") Cc: Al Viro Cc: Christian Brauner Cc: Jan Kara Cc: stable@kernel.org Signed-off-by: Jann Horn Signed-off-by: Linus Torvalds

Merge tag 'vfs-7.1-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-06-06T14:28:59+00:00

Pull vfs fixes from Christian Brauner: - Fix error handling in ovl_cache_get() - Tighten access checks for exited tasks in pidfd_getfd() - Fix selftests leak in __wait_for_test() - Limit FUSE_NOTIFY_RETRIEVE to uptodate folios - Reject fuse_notify() pagecache ops on directories - Clear JOBCTL_PENDING_MASK for caller in zap_other_threads() - Fix failure to unlock in nfsd4_create_file() - Fix pointer arithmetic in qnx6 directory iteration - Fix UAF due to unlocked ->mnt_ns read in may_decode_fh() - Avoid potential null folio->mapping deref during iomap error reporting * tag 'vfs-7.1-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: iomap: avoid potential null folio->mapping deref during error reporting fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() fs/qnx6: fix pointer arithmetic in directory iteration VFS: fix possible failure to unlock in nfsd4_create_file() signal: clear JOBCTL_PENDING_MASK for caller in zap_other_threads() fuse: reject fuse_notify() pagecache ops on directories fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios selftests: harness: fix pidfd leak in __wait_for_test pidfd: refuse access to tasks that have started exiting harder ovl: keep err zero after successful ovl_cache_get()

Merge tag 'nfs-for-7.1-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2026-06-05T16:34:14+00:00

Pull NFS client fix from Trond Myklebust: - Fix a use after free in nfs_write_completion * tag 'nfs-for-7.1-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: NFS: write_completion: dereference loop-local req, not hdr->req

Merge tag 'xfs-fixes-7.1-rc7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

2026-06-05T15:34:32+00:00

Pull xfs fixes from Carlos Maiolino: "A collection of fixes mostly for the RT device, including a small refactor that has no functional change" * tag 'xfs-fixes-7.1-rc7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: Remove mention of PageWriteback xfs: abort mount if xfs_fs_reserve_ag_blocks fails xfs: factor rtgroup geom write pointer reporting into a helper xfs: drop the RTG reference later in xfs_ioc_rtgroup_geometry xfs: fix rtgroup cleanup in CoW fork repair xfs: fix error returns in CoW fork repair xfs: fix overlapping extents returned for pNFS LAYOUTGET xfs: fix use of uninitialized imap in xfs_fs_map_blocks error path xfs: handle racing deletions in xfs_zone_gc_iter_irec

Merge tag 'erofs-for-7.1-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

2026-06-05T15:28:10+00:00

Pull erofs fixes from Gao Xiang: - Fix a UAF of sbi->sync_decompress when compressed I/Os race with unmount - Fix a regression introduced this development cycle that incorrectly rejects multiple-algorithm images * tag 'erofs-for-7.1-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs: erofs: fix EFSCORRUPTED on multi-algorithm images in z_erofs_map_sanity_check() erofs: fix use-after-free on sbi->sync_decompress