Development tree for the kernel CSPRNG https://git.zx2c4.com/linux-rng/atom/arch/powerpc?h=master 2025-12-02T16:01:39Z 2025-12-02T16:01:39Z Linus Torvalds torvalds@linux-foundation.org 2025-12-02T16:01:39Z urn:sha1:1dce50698a5ceedaca806e0a78573886a363dc95 Pull scoped user access updates from Thomas Gleixner: "Scoped user mode access and related changes: - Implement the missing u64 user access function on ARM when CONFIG_CPU_SPECTRE=n. This makes it possible to access a 64bit value in generic code with [unsafe_]get_user(). All other architectures and ARM variants provide the relevant accessors already. - Ensure that ASM GOTO jump label usage in the user mode access helpers always goes through a local C scope label indirection inside the helpers. This is required because compilers are not supporting that a ASM GOTO target leaves a auto cleanup scope. GCC silently fails to emit the cleanup invocation and CLANG fails the build. [ Editor's note: gcc-16 will have fixed the code generation issue in commit f68fe3ddda4 ("eh: Invoke cleanups/destructors in asm goto jumps [PR122835]"). But we obviously have to deal with clang and older versions of gcc, so.. - Linus ] This provides generic wrapper macros and the conversion of affected architecture code to use them. - Scoped user mode access with auto cleanup Access to user mode memory can be required in hot code paths, but if it has to be done with user controlled pointers, the access is shielded with a speculation barrier, so that the CPU cannot speculate around the address range check. Those speculation barriers impact performance quite significantly. This cost can be avoided by "masking" the provided pointer so it is guaranteed to be in the valid user memory access range and otherwise to point to a guaranteed unpopulated address space. This has to be done without branches so it creates an address dependency for the access, which the CPU cannot speculate ahead. This results in repeating and error prone programming patterns: if (can_do_masked_user_access()) from = masked_user_read_access_begin((from)); else if (!user_read_access_begin(from, sizeof(*from))) return -EFAULT; unsafe_get_user(val, from, Efault); user_read_access_end(); return 0; Efault: user_read_access_end(); return -EFAULT; which can be replaced with scopes and automatic cleanup: scoped_user_read_access(from, Efault) unsafe_get_user(val, from, Efault); return 0; Efault: return -EFAULT; - Convert code which implements the above pattern over to scope_user.*.access(). This also corrects a couple of imbalanced masked_*_begin() instances which are harmless on most architectures, but prevent PowerPC from implementing the masking optimization. - Add a missing speculation barrier in copy_from_user_iter()" * tag 'core-uaccess-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lib/strn*,uaccess: Use masked_user_{read/write}_access_begin when required scm: Convert put_cmsg() to scoped user access iov_iter: Add missing speculation barrier to copy_from_user_iter() iov_iter: Convert copy_from_user_iter() to masked user access select: Convert to scoped user access x86/futex: Convert to scoped user access futex: Convert to get/put_user_inline() uaccess: Provide put/get_user_inline() uaccess: Provide scoped user access regions arm64: uaccess: Use unsafe wrappers for ASM GOTO s390/uaccess: Use unsafe wrappers for ASM GOTO riscv/uaccess: Use unsafe wrappers for ASM GOTO powerpc/uaccess: Use unsafe wrappers for ASM GOTO x86/uaccess: Use unsafe wrappers for ASM GOTO uaccess: Provide ASM GOTO safe wrappers for unsafe_*_user() ARM: uaccess: Implement missing __get_user_asm_dword() 2025-12-02T05:33:01Z Linus Torvalds torvalds@linux-foundation.org 2025-12-02T05:33:01Z urn:sha1:4a26e7032d7d57c998598c08a034872d6f0d3945 Pull bug handling infrastructure updates from Ingo Molnar: "Core updates: - Improve WARN(), which has vararg printf like arguments, to work with the x86 #UD based WARN-optimizing infrastructure by hiding the format in the bug_table and replacing this first argument with the address of the bug-table entry, while making the actual function that's called a UD1 instruction (Peter Zijlstra) - Introduce the CONFIG_DEBUG_BUGVERBOSE_DETAILED Kconfig switch (Ingo Molnar, s390 support by Heiko Carstens) Fixes and cleanups: - bugs/s390: Remove private WARN_ON() implementation (Heiko Carstens) - <asm/bugs.h>: Make i386 use GENERIC_BUG_RELATIVE_POINTERS (Peter Zijlstra)" * tag 'core-bugs-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/bugs: Make i386 use GENERIC_BUG_RELATIVE_POINTERS x86/bug: Fix BUG_FORMAT vs KASLR x86_64/bug: Inline the UD1 x86/bug: Implement WARN_ONCE() x86_64/bug: Implement __WARN_printf() x86/bug: Use BUG_FORMAT for DEBUG_BUGVERBOSE_DETAILED x86/bug: Add BUG_FORMAT basics bug: Allow architectures to provide __WARN_printf() bug: Implement WARN_ON() using __WARN_FLAGS() bug: Add report_bug_entry() bug: Add BUG_FORMAT_ARGS infrastructure bug: Clean up CONFIG_GENERIC_BUG_RELATIVE_POINTERS bug: Add BUG_FORMAT infrastructure x86: Rework __bug_table helpers bugs/s390: Remove private WARN_ON() implementation bugs/core: Reorganize fields in the first line of WARNING output, add ->comm[] output bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output bugs/parisc: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output bugs/riscv: Concatenate 'cond_str' with '__FILE__' in __BUG_FLAGS(), to extend WARN_ON/BUG_ON output bugs/riscv: Pass in 'cond_str' to __BUG_FLAGS() ... 2025-12-02T01:32:07Z Linus Torvalds torvalds@linux-foundation.org 2025-12-02T01:32:07Z urn:sha1:1b5dd29869b1e63f7e5c37d7552e2dcf22de3c26 Pull fd prepare updates from Christian Brauner: "This adds the FD_ADD() and FD_PREPARE() primitive. They simplify the common pattern of get_unused_fd_flags() + create file + fd_install() that is used extensively throughout the kernel and currently requires cumbersome cleanup paths. FD_ADD() - For simple cases where a file is installed immediately: fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device)); if (fd < 0) vfio_device_put_registration(device); return fd; FD_PREPARE() - For cases requiring access to the fd or file, or additional work before publishing: FD_PREPARE(fdf, O_CLOEXEC, sync_file->file); if (fdf.err) { fput(sync_file->file); return fdf.err; } data.fence = fd_prepare_fd(fdf); if (copy_to_user((void __user *)arg, &data, sizeof(data))) return -EFAULT; return fd_publish(fdf); The primitives are centered around struct fd_prepare. FD_PREPARE() encapsulates all allocation and cleanup logic and must be followed by a call to fd_publish() which associates the fd with the file and installs it into the caller's fdtable. If fd_publish() isn't called, both are deallocated automatically. FD_ADD() is a shorthand that does fd_publish() immediately and never exposes the struct to the caller. I've implemented this in a way that it's compatible with the cleanup infrastructure while also being usable separately. IOW, it's centered around struct fd_prepare which is aliased to class_fd_prepare_t and so we can make use of all the basica guard infrastructure" * tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits) io_uring: convert io_create_mock_file() to FD_PREPARE() file: convert replace_fd() to FD_PREPARE() vfio: convert vfio_group_ioctl_get_device_fd() to FD_ADD() tty: convert ptm_open_peer() to FD_ADD() ntsync: convert ntsync_obj_get_fd() to FD_PREPARE() media: convert media_request_alloc() to FD_PREPARE() hv: convert mshv_ioctl_create_partition() to FD_ADD() gpio: convert linehandle_create() to FD_PREPARE() pseries: port papr_rtas_setup_file_interface() to FD_ADD() pseries: convert papr_platform_dump_create_handle() to FD_ADD() spufs: convert spufs_gang_open() to FD_PREPARE() papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE() spufs: convert spufs_context_open() to FD_PREPARE() net/socket: convert __sys_accept4_file() to FD_ADD() net/socket: convert sock_map_fd() to FD_ADD() net/kcm: convert kcm_ioctl() to FD_PREPARE() net/handshake: convert handshake_nl_accept_doit() to FD_PREPARE() secretmem: convert memfd_secret() to FD_ADD() memfd: convert memfd_create() to FD_ADD() bpf: convert bpf_token_create() to FD_PREPARE() ... 2025-12-01T17:47:41Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T17:47:41Z urn:sha1:415d34b92c1f921a9ff3c38f56319cbc5536f642 Pull namespace updates from Christian Brauner: "This contains substantial namespace infrastructure changes including a new system call, active reference counting, and extensive header cleanups. The branch depends on the shared kbuild branch for -fms-extensions support. Features: - listns() system call Add a new listns() system call that allows userspace to iterate through namespaces in the system. This provides a programmatic interface to discover and inspect namespaces, addressing longstanding limitations: Currently, there is no direct way for userspace to enumerate namespaces. Applications must resort to scanning /proc/*/ns/ across all processes, which is: - Inefficient - requires iterating over all processes - Incomplete - misses namespaces not attached to any running process but kept alive by file descriptors, bind mounts, or parent references - Permission-heavy - requires access to /proc for many processes - No ordering or ownership information - No filtering per namespace type The listns() system call solves these problems: ssize_t listns(const struct ns_id_req *req, u64 *ns_ids, size_t nr_ns_ids, unsigned int flags); struct ns_id_req { __u32 size; __u32 spare; __u64 ns_id; struct /* listns */ { __u32 ns_type; __u32 spare2; __u64 user_ns_id; }; }; Features include: - Pagination support for large namespace sets - Filtering by namespace type (MNT_NS, NET_NS, USER_NS, etc.) - Filtering by owning user namespace - Permission checks respecting namespace isolation - Active Reference Counting Introduce an active reference count that tracks namespace visibility to userspace. A namespace is visible in the following cases: - The namespace is in use by a task - The namespace is persisted through a VFS object (namespace file descriptor or bind-mount) - The namespace is a hierarchical type and is the parent of child namespaces The active reference count does not regulate lifetime (that's still done by the normal reference count) - it only regulates visibility to namespace file handles and listns(). This prevents resurrection of namespaces that are pinned only for internal kernel reasons (e.g., user namespaces held by file->f_cred, lazy TLB references on idle CPUs, etc.) which should not be accessible via (1)-(3). - Unified Namespace Tree Introduce a unified tree structure for all namespaces with: - Fixed IDs assigned to initial namespaces - Lookup based solely on inode number - Maintained list of owned namespaces per user namespace - Simplified rbtree comparison helpers Cleanups - Header Reorganization: - Move namespace types into separate header (ns_common_types.h) - Decouple nstree from ns_common header - Move nstree types into separate header - Switch to new ns_tree_{node,root} structures with helper functions - Use guards for ns_tree_lock - Initial Namespace Reference Count Optimization - Make all reference counts on initial namespaces a nop to avoid pointless cacheline ping-pong for namespaces that can never go away - Drop custom reference count initialization for initial namespaces - Add NS_COMMON_INIT() macro and use it for all namespaces - pid: rely on common reference count behavior - Miscellaneous Cleanups - Rename exit_task_namespaces() to exit_nsproxy_namespaces() - Rename is_initial_namespace() and make argument const - Use boolean to indicate anonymous mount namespace - Simplify owner list iteration in nstree - nsfs: raise SB_I_NODEV, SB_I_NOEXEC, and DCACHE_DONTCACHE explicitly - nsfs: use inode_just_drop() - pidfs: raise DCACHE_DONTCACHE explicitly - pidfs: simplify PIDFD_GET__NAMESPACE ioctls - libfs: allow to specify s_d_flags - cgroup: add cgroup namespace to tree after owner is set - nsproxy: fix free_nsproxy() and simplify create_new_namespaces() Fixes: - setns(pidfd, ...) race condition Fix a subtle race when using pidfds with setns(). When the target task exits after prepare_nsset() but before commit_nsset(), the namespace's active reference count might have been dropped. If setns() then installs the namespaces, it would bump the active reference count from zero without taking the required reference on the owner namespace, leading to underflow when later decremented. The fix resurrects the ownership chain if necessary - if the caller succeeded in grabbing passive references, the setns() should succeed even if the target task exits or gets reaped. - Return EFAULT on put_user() error instead of success - Make sure references are dropped outside of RCU lock (some namespaces like mount namespace sleep when putting the last reference) - Don't skip active reference count initialization for network namespace - Add asserts for active refcount underflow - Add asserts for initial namespace reference counts (both passive and active) - ipc: enable is_ns_init_id() assertions - Fix kernel-doc comments for internal nstree functions - Selftests - 15 active reference count tests - 9 listns() functionality tests - 7 listns() permission tests - 12 inactive namespace resurrection tests - 3 threaded active reference count tests - commit_creds() active reference tests - Pagination and stress tests - EFAULT handling test - nsid tests fixes" * tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (103 commits) pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls nstree: fix kernel-doc comments for internal functions nsproxy: fix free_nsproxy() and simplify create_new_namespaces() selftests/namespaces: fix nsid tests ns: drop custom reference count initialization for initial namespaces pid: rely on common reference count behavior ns: add asserts for initial namespace active reference counts ns: add asserts for initial namespace reference counts ns: make all reference counts on initial namespace a nop ipc: enable is_ns_init_id() assertions fs: use boolean to indicate anonymous mount namespace ns: rename is_initial_namespace() ns: make is_initial_namespace() argument const nstree: use guards for ns_tree_lock nstree: simplify owner list iteration nstree: switch to new structures nstree: add helper to operate on struct ns_tree_{node,root} nstree: move nstree types into separate header nstree: decouple from ns_common header ns: move namespace types into separate header ... 2025-12-01T16:44:26Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T16:44:26Z urn:sha1:b04b2e7a61830cabd00c6f95308a8e2f5d82fa52 Pull misc vfs updates from Christian Brauner: "Features: - Cheaper MAY_EXEC handling for path lookup. This elides MAY_WRITE permission checks during path lookup and adds the IOP_FASTPERM_MAY_EXEC flag so filesystems like btrfs can avoid expensive permission work. - Hide dentry_cache behind runtime const machinery. - Add German Maglione as virtiofs co-maintainer. Cleanups: - Tidy up and inline step_into() and walk_component() for improved code generation. - Re-enable IOCB_NOWAIT writes to files. This refactors file timestamp update logic, fixing a layering bypass in btrfs when updating timestamps on device files and improving FMODE_NOCMTIME handling in VFS now that nfsd started using it. - Path lookup optimizations extracting slowpaths into dedicated routines and adding branch prediction hints for mntput_no_expire(), fd_install(), lookup_slow(), and various other hot paths. - Enable clang's -fms-extensions flag, requiring a JFS rename to avoid conflicts. - Remove spurious exports in fs/file_attr.c. - Stop duplicating union pipe_index declaration. This depends on the shared kbuild branch that brings in -fms-extensions support which is merged into this branch. - Use MD5 library instead of crypto_shash in ecryptfs. - Use largest_zero_folio() in iomap_dio_zero(). - Replace simple_strtol/strtoul with kstrtoint/kstrtouint in init and initrd code. - Various typo fixes. Fixes: - Fix emergency sync for btrfs. Btrfs requires an explicit sync_fs() call with wait == 1 to commit super blocks. The emergency sync path never passed this, leaving btrfs data uncommitted during emergency sync. - Use local kmap in watch_queue's post_one_notification(). - Add hint prints in sb_set_blocksize() for LBS dependency on THP" * tag 'vfs-6.19-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits) MAINTAINERS: add German Maglione as virtiofs co-maintainer fs: inline step_into() and walk_component() fs: tidy up step_into() & friends before inlining orangefs: use inode_update_timestamps directly btrfs: fix the comment on btrfs_update_time btrfs: use vfs_utimes to update file timestamps fs: export vfs_utimes fs: lift the FMODE_NOCMTIME check into file_update_time_flags fs: refactor file timestamp update logic include/linux/fs.h: trivial fix: regualr -> regular fs/splice.c: trivial fix: pipes -> pipe's fs: mark lookup_slow() as noinline fs: add predicts based on nd->depth fs: move mntput_no_expire() slowpath into a dedicated routine fs: remove spurious exports in fs/file_attr.c watch_queue: Use local kmap in post_one_notification() fs: touch up predicts in path lookup fs: move fd_install() slowpath into a dedicated routine and provide commentary fs: hide dentry_cache behind runtime const machinery fs: touch predicts in do_dentry_open() ... 2025-11-28T11:42:35Z Christian Brauner brauner@kernel.org 2025-11-23T16:33:54Z urn:sha1:6ae8da4846526e8af1d5132847716de9e6706f37 Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-36-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> 2025-11-28T11:42:35Z Christian Brauner brauner@kernel.org 2025-11-23T16:33:53Z urn:sha1:274d937006a2f1258f513cca3f8d56fc23466b0e Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-35-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> 2025-11-28T11:42:35Z Christian Brauner brauner@kernel.org 2025-11-23T16:33:52Z urn:sha1:0b9d4a6b51d75ca3e9806bf660e147328d645378 Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-34-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> 2025-11-28T11:42:35Z Christian Brauner brauner@kernel.org 2025-11-23T16:33:51Z urn:sha1:6d3789d347a7af5c4b0b2da3af47b8d9da607ab2 Fixes a UAF for src_info as well. Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-33-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> 2025-11-28T11:42:34Z Christian Brauner brauner@kernel.org 2025-11-23T16:33:50Z urn:sha1:843e7b5c293c112dedeeced1a7088668933d3308 Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-32-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>