aboutsummaryrefslogtreecommitdiff
path: root/fs/exec.c
AgeCommit message (Collapse)AuthorFilesLines
2026-07-01exec: fix off-by-one in binfmt max rewrite depth commentAlan Urmancheev1-1/+1
The loop in exec_binprm() permits depth values 0 through 5, up to 5 successive binfmt rewrites (setting bprm->interpreter) until the 6th one would fail on depth > 5 and return -ELOOP. The comment claimed 4 levels, which was wrong. Adjusting the code to allow only 4 rewrites would be breaking userland, so fix the comment and not the code. Reproducer (a chain of shebanged scripts followed by an ELF binary): #!/bin/sh tmp=$(mktemp -d) echo $tmp cd $tmp mk () { echo $2 > $1; chmod +x $1; } for i in $(seq 4); do mk $i "#!$((i + 1))" done mk 5 '#!/bin/true' ./1 && echo '5 binfmt rewrites OK (1 -> 2 -> 3 -> 4 -> 5 -> /bin/true)' mk 5 '#!6' mk 6 '#!/bin/true' ./1 || echo '6 binfmt rewrites KO (1 -> 2 -> 3 -> 4 -> 5 -> 6 -> /bin/true)' Signed-off-by: Alan Urmancheev <alan.urman@gmail.com> Link: https://patch.msgid.link/20260623052322.74711-1-alan.urman@gmail.com Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-06-15Merge tag 'vfs-7.2-rc1.misc' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "Features: - Reduce pipe->mutex contention by pre-allocating pages outside the lock in anon_pipe_write(). anon_pipe_write() called alloc_page() once per page while holding pipe->mutex. The allocation can sleep doing direct reclaim and runs memcg charging, which extends the critical section and stalls any concurrent reader on the same mutex. Now up to 8 pages are pre-allocated before the mutex is taken, leftovers are recycled into the per-pipe tmp_page[] cache before unlock, and any remainder is released after unlock, keeping the allocator out of the critical section on both sides. On a writers x readers sweep with 64KB writes against a 1 MB pipe throughput improves 6-28% and average write latency drops 5-22%; under memory pressure - when the cost of holding the mutex across reclaim is highest - throughput improves 21-48% and latency drops 17-33%. The microbenchmark is added to selftests. - uaccess/sockptr: fix the ignored_trailing logic in copy_struct_to_user() to behave as documented and the usize check in copy_struct_from_sockptr() for user pointers, and add copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr() helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC). - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real inode backing a dentry via d_real_inode(). On overlayfs the inode attached to the dentry doesn't carry the underlying device information; this is used by the filesystem restriction BPF program that was merged into systemd. - docs: add guidelines for submitting new filesystems, motivated by the maintenance burden abandoned and untestable filesystems impose on VFS developers, blocking infrastructure work like folio conversions and iomap migration. Fixes: - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() and drop the now-redundant assignments in callers. This began as a one-line dma-buf fix for a path_noexec() warning; a pseudo filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo() callers were audited: the only visible effect is on dma-buf where SB_I_NOEXEC silences the warning. - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs, qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a device with a sector size > PAGE_SIZE crashed roughly half of them; the rest had the same missing error handling pattern. Plus a follow-up releasing the superblock buffer_head when setting the minix v3 block size fails. - mount: honour SB_NOUSER in the new mount API. - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by switching the process-group paths of send_sigio() and send_sigurg() from read_lock(&tasklist_lock) to RCU, matching the single-PID path. - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing delegated NFS mounts (fsopen() in a container with the mount performed by a privileged daemon) that broke when non-init s_user_ns was tied to FS_USERNS_MOUNT. - selftests/namespaces: fix a hang in nsid_test where an unreaped grandchild kept the TAP pipe write-end open, a waitpid(-1) race in listns_efault_test, and a false FAIL on kernels without listns() where the tests should SKIP. - filelock: fix the break_lease() stub signature for CONFIG_FILE_LOCKING=n. - init/initramfs_test: wait for the async initramfs unpacking before running; the test and do_populate_rootfs() share the parser state. - fs/coredump: reduce redundant log noise in validate_coredump_safety(). - iomap: pass the correct length to fserror_report_io() in __iomap_write_begin(). - backing-file: fix the backing_file_open() kerneldoc. Cleanups: - initramfs: refactor the cpio hex header parsing to use hex2bin() instead of the hand-rolled simple_strntoul() which is reverted, and extend the initramfs KUnit tests to cover header fields with 0x prefixes. - Replace __get_free_pages() and friends with kmalloc()/kzalloc() across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2, isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the do_mounts init code - part of the larger work of replacing page allocator calls with kmalloc(). - Use clear_and_wake_up_bit() in unlock_buffer() and journal_end_buffer_io_sync() instead of open-coding the sequence. - Drop unused VFS exports: unexport drop_super_exclusive(), remove start_removing_user_path_at(), and fold __start_removing_path() into start_removing_path(). - fs/read_write: narrow the __kernel_write() export with EXPORT_SYMBOL_FOR_MODULES(). - vfs: uapi: retire octal and hex constants in favor of (1 << n) for the O_ flags. Finding a free bit for a new flag across the architectures was needlessly hard with the mixed bases. - dcache: add extra sanity checks of dead dentries in dentry_free() via a new DENTRY_WARN_ONCE() that also prints d_flags. - iov_iter: use kmemdup_array() in dup_iter() to harden the allocation against multiplication overflow. - fs/pipe: write to ->poll_usage only once. - vfs: remove an always-taken if-branch in find_next_fd(). - dcache: use kmalloc_flex() for struct external_name in __d_alloc(). - namei: use QSTR() instead of QSTR_INIT() in path_pts(). - sync_file_range: delete dead S_ISLNK code. - Comment fixes: retire a stale comment in fget_task_next() and fix assorted spelling mistakes" * tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits) backing-file: fix backing_file_open() kerneldoc parameter iomap: pass the correct len to fserror_report_io in __iomap_write_begin vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags bpf: add bpf_real_inode() kfunc fs/read_write: Do not export __kernel_write() to the entire world libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() mount: honour SB_NOUSER in the new mount API fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling selftests/pipe: add pipe_bench microbenchmark fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write fs: retire stale comment in fget_task_next() fs: fix spelling mistakes in comment bfs: replace get_zeroed_page() with kzalloc() binfmt_misc: replace __get_free_page() with kmalloc() configfs: replace __get_free_pages() with kzalloc() fs/namespace: use __getname() to allocate mntpath buffer fs/select: replace __get_free_page() with kmalloc() ...
2026-05-26exec: free the old mm outside the exec locksChristian Brauner1-7/+25
exec_mmap() installs the new mm and then tears the old one down while still holding exec_update_lock for writing -- and with cred_guard_mutex held all the way to setup_new_exec(): setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); mm_update_next_owner(old_mm); mmput(old_mm); Neither lock is needed for this. exec_update_lock only exists to make the mm swap atomic with the later commit_creds(), so that permission-checking readers (proc, ptrace, the futex robust list, perf, kcmp, mm_access()) never observe the new mm together with the old credentials. Those readers all operate on task->mm, i.e. the new mm after the swap; none looks at the detached old mm, its ->owner or signal->maxrss. cred_guard_mutex guards credential calculation and is equally irrelevant here. The cost is real: __mmput() runs exit_mmap() over the entire old address space and can block in exit_aio() waiting for in-flight AIO, all while holding exec_update_lock for writing and cred_guard_mutex. For execve() of a large process this blocks ptrace_attach() and every exec_update_lock reader for the duration of the teardown. Stash the old mm in bprm->old_mm and release it from setup_new_exec() after both locks are dropped. setup_new_exec() still runs before setup_arg_pages() and the segment mappings, so the old address space is freed before the new one is populated and peak memory is unchanged. The ordering constraints are kept: old_mm's mmap_lock is still dropped in exec_mmap() before mm_update_next_owner() (required since commit 31a78f23bac0 ("mm owner: fix race between swapoff and exit")), and mm_update_next_owner() still precedes mmput(); both run in the execing task's context, as mm_update_next_owner() requires. If exec swaps the mm but fails before setup_new_exec() runs the old mm would leak, so add a backstop in free_bprm(). The lazy-tlb case (old_mm == NULL, e.g. kernel_execve()) has no address space to free and is left in exec_mmap(). Link: https://patch.msgid.link/20260522-work-exit_mm-v1-1-bd32d5a560bb@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-05-26exec_state: relocate dumpable informationChristian Brauner (Amutable)1-19/+20
The dumpable flag captured at execve() is consulted by __ptrace_may_access() and several /proc owner / visibility checks. It lives on mm_struct today, which exit_mm() clears from the task long before the task itself is reaped. exec_state is anchored to the execve() that established the current privilege domain. CLONE_VM siblings refcount-share the parent's exec_state via copy_exec_state(); non-CLONE_VM clones allocate a fresh exec_state inheriting the parent's dumpable mode and user_ns reference via task_exec_state_copy(). execve() allocates a fresh instance (via alloc_task_exec_state() in begin_new_exec()) and installs it under task_lock + exec_update_lock with task_exec_state_replace(). init_task uses a static instance. The dumpable mode now lives on task->exec_state->dumpable. task->mm->flags no longer carries dumpability; MMF_DUMPABLE_MASK is removed, but MMF_DUMPABLE_BITS is reserved so MMF_DUMP_FILTER_* bit positions remain stable for the /proc/<pid>/coredump_filter ABI. The task->user_dumpable cache bit and its assignment in exit_mm() are removed; readers go through get_dumpable(task) directly. coredump_params gains a snapshot field cprm.dumpable, populated from get_dumpable(current) at vfs_coredump() entry, replacing the previous __get_dumpable(cprm->mm_flags) consumers in fs/coredump.c and fs/pidfs.c. The user namespace recorded at execve() is consulted by __ptrace_may_access() and by /proc/PID/* owner derivation. Move the captured user_ns onto task_exec_state, which stays attached to the task past exit_mm() and across exit_files(). bprm grows a user_ns field staged in bprm_mm_init() with the caller's user_ns, narrowed by would_dump() to the closest privileged ancestor, and consumed by exec_mmap() via alloc_task_exec_state(bprm->user_ns). free_bprm() releases the staging reference. mm_struct loses ->user_ns entirely. Initializers in init-mm, efi_mm, and the implicit one in mm_init()/dup_mm()/mm_alloc() are removed; __mmdrop() drops the matching put_user_ns(). The kthread_use_mm() WARN_ON_ONCE(!mm->user_ns) is no longer meaningful and goes too. Reviewed-by: Jann Horn <jannh@google.com> Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-4-69f895bc1385@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-05-26sched/coredump: introduce enum task_dumpableChristian Brauner (Amutable)1-4/+4
Replace the SUID_DUMP_DISABLE/USER/ROOT preprocessor constants with enum task_dumpable. Numeric values are preserved (kernel.suid_dumpable sysctl and prctl(PR_SET_DUMPABLE) ABI), so this is a pure rename with no behavioral change. Subsequent commits relocate dumpability onto a per-task structure where the enum type will allow stronger type-checking on the new API. Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: David Hildenbrand (arm) <david@kernel.org> Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-1-69f895bc1385@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-05-21fs/coredump: reduce redundant log noise in validate_coredump_safetyLi RongQing1-2/+4
Currently, writing to 'core_pattern' or 'suid_dumpable' sysctl nodes always triggers validate_coredump_safety(), even if the values have not changed. This results in redundant warning messages in dmesg: "Unsafe core_pattern used with fs.suid_dumpable=2..." This patch optimizes the procfs handlers to only invoke the safety validation when an actual change in the configuration is detected: 1. In proc_dostring_coredump(), compare the new core_pattern string with the existing one using strncmp(). 2. In proc_dointvec_minmax_coredump(), check if the new suid_dumpable value differs from the previous one. This keeps the kernel log clean from repetitive warnings when re-applying the same sysctl settings. Signed-off-by: Li RongQing <lirongqing@baidu.com> Link: https://patch.msgid.link/20260410080918.2319-1-lirongqing@baidu.com Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-04-01exec: use strnlen() in __set_task_commThorsten Blum1-1/+1
Use strnlen() to limit source string scanning to 'TASK_COMM_LEN - 1' bytes. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20260401152039.724811-3-thorsten.blum@linux.dev Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds1-1/+1
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook1-1/+1
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-09Merge tag 'pull-filename' of ↵Linus Torvalds1-124/+54
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'struct filename' updates from Al Viro: "[Mostly] sanitize struct filename handling" * tag 'pull-filename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (68 commits) sysfs(2): fs_index() argument is _not_ a pathname alpha: switch osf_mount() to strndup_user() ksmbd: use CLASS(filename_kernel) mqueue: switch to CLASS(filename) user_statfs(): switch to CLASS(filename) statx: switch to CLASS(filename_maybe_null) quotactl_block(): switch to CLASS(filename) chroot(2): switch to CLASS(filename) move_mount(2): switch to CLASS(filename_maybe_null) namei.c: switch user pathname imports to CLASS(filename{,_flags}) namei.c: convert getname_kernel() callers to CLASS(filename_kernel) do_f{chmod,chown,access}at(): use CLASS(filename_uflags) do_readlinkat(): switch to CLASS(filename_flags) do_sys_truncate(): switch to CLASS(filename) do_utimes_path(): switch to CLASS(filename_uflags) chdir(2): unspaghettify a bit... do_fchownat(): unspaghettify a bit... fspick(2): use CLASS(filename_flags) name_to_handle_at(): use CLASS(filename_uflags) vfs_open_tree(): use CLASS(filename_uflags) ...
2026-01-16do_open_execat(): don't care about LOOKUP_EMPTYAl Viro1-2/+0
do_file_open() doesn't. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13switch {alloc,free}_bprm() to CLASS()Al Viro1-27/+21
All linux_binprm instances come from alloc_bprm() and are unconditionally destroyed by free_bprm() in the end of the same scope. IOW, CLASS() machinery is a decent fit for those. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13do_execveat_common(): don't consume filename referenceAl Viro1-15/+12
... and convert its callers to CLASS(filename...) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13execve: fold {compat_,}do_execve{,at}() into their sole callersAl Viro1-61/+19
All of them are wrappers for do_execveat_common() and each has exactly one caller. The only difference is in the way they are constructing argv/envp arguments for do_execveat_common() and that's easy to do with less boilerplate. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13simplify the callers of alloc_bprm()Al Viro1-14/+3
alloc_bprm() starts with do_open_execat() and it will do the right thing if given ERR_PTR() for name. Allows to drop such checks in its callers... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13simplify the callers of do_open_execat()Al Viro1-8/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13rename do_filp_open() to do_file_open()Al Viro1-1/+1
"filp" thing never made sense; seeing that there are exactly 4 callers in the entire tree (and it's neither exported nor even declared in linux/*/*.h), there's no point keeping that ugliness. FWIW, the 'filp' thing did originate in OSD&I; for some reason Tanenbaum decided to call the object representing an opened file 'struct filp', the last letter standing for 'position'. In all Unices, Linux included, the corresponding object had always been 'struct file'... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-12-15fs: use min() or umin() instead of min_t()David Laight1-1/+1
min_t(unsigned int, a, b) casts an 'unsigned long' to 'unsigned int'. Use min(a, b) instead as it promotes any 'unsigned int' to 'unsigned long' and so cannot discard significant bits. A couple of places need umin() because of loops like: nfolios = DIV_ROUND_UP(ret + start, PAGE_SIZE); for (i = 0; i < nfolios; i++) { struct folio *folio = page_folio(pages[i]); ... unsigned int len = umin(ret, PAGE_SIZE - start); ... ret -= len; ... } where the compiler doesn't track things well enough to know that 'ret' is never negative. The alternate loop: for (i = 0; ret > 0; i++) { struct folio *folio = page_folio(pages[i]); ... unsigned int len = min(ret, PAGE_SIZE - start); ... ret -= len; ... } would be equivalent and doesn't need 'nfolios'. Most of the 'unsigned long' actually come from PAGE_SIZE. Detected by an extra check added to min_t(). Signed-off-by: David Laight <david.laight.linux@gmail.com> Link: https://patch.msgid.link/20251119224140.8616-31-david.laight.linux@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-12-02Merge tag 'core-rseq-2025-11-30' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull rseq updates from Thomas Gleixner: "A large overhaul of the restartable sequences and CID management: The recent enablement of RSEQ in glibc resulted in regressions which are caused by the related overhead. It turned out that the decision to invoke the exit to user work was not really a decision. More or less each context switch caused that. There is a long list of small issues which sums up nicely and results in a 3-4% regression in I/O benchmarks. The other detail which caused issues due to extra work in context switch and task migration is the CID (memory context ID) management. It also requires to use a task work to consolidate the CID space, which is executed in the context of an arbitrary task and results in sporadic uncontrolled exit latencies. The rewrite addresses this by: - Removing deprecated and long unsupported functionality - Moving the related data into dedicated data structures which are optimized for fast path processing. - Caching values so actual decisions can be made - Replacing the current implementation with a optimized inlined variant. - Separating fast and slow path for architectures which use the generic entry code, so that only fault and error handling goes into the TIF_NOTIFY_RESUME handler. - Rewriting the CID management so that it becomes mostly invisible in the context switch path. That moves the work of switching modes into the fork/exit path, which is a reasonable tradeoff. That work is only required when a process creates more threads than the cpuset it is allowed to run on or when enough threads exit after that. An artificial thread pool benchmarks which triggers this did not degrade, it actually improved significantly. The main effect in migration heavy scenarios is that runqueue lock held time and therefore contention goes down significantly" * tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits) sched/mmcid: Switch over to the new mechanism sched/mmcid: Implement deferred mode change irqwork: Move data struct to a types header sched/mmcid: Provide CID ownership mode fixup functions sched/mmcid: Provide new scheduler CID mechanism sched/mmcid: Introduce per task/CPU ownership infrastructure sched/mmcid: Serialize sched_mm_cid_fork()/exit() with a mutex sched/mmcid: Provide precomputed maximal value sched/mmcid: Move initialization out of line signal: Move MMCID exit out of sighand lock sched/mmcid: Convert mm CID mask to a bitmap cpumask: Cache num_possible_cpus() sched/mmcid: Use cpumask_weighted_or() cpumask: Introduce cpumask_weighted_or() sched/mmcid: Prevent pointless work in mm_update_cpus_allowed() sched/mmcid: Move scheduler code out of global header sched: Fixup whitespace damage sched/mmcid: Cacheline align MM CID storage sched/mmcid: Use proper data structures sched/mmcid: Revert the complex CID management ...
2025-12-01Merge tag 'vfs-6.19-rc1.fd_prepare.fs' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 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() ...
2025-11-28exec: convert begin_new_exec() to FD_ADD()Christian Brauner1-2/+1
Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-21-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-04rseq: Optimize event settingThomas Gleixner1-1/+1
After removing the various condition bits earlier it turns out that one extra information is needed to avoid setting event::sched_switch and TIF_NOTIFY_RESUME unconditionally on every context switch. The update of the RSEQ user space memory is only required, when either the task was interrupted in user space and schedules or the CPU or MM CID changes in schedule() independent of the entry mode Right now only the interrupt from user information is available. Add an event flag, which is set when the CPU or MM CID or both change. Evaluate this event in the scheduler to decide whether the sched_switch event and the TIF bit need to be set. It's an extra conditional in context_switch(), but the downside of unconditionally handling RSEQ after a context switch to user is way more significant. The utilized boolean logic minimizes this to a single conditional branch. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084307.578058898@linutronix.de
2025-11-04rseq: Simplify the event notificationThomas Gleixner1-1/+1
Since commit 0190e4198e47 ("rseq: Deprecate RSEQ_CS_FLAG_NO_RESTART_ON_* flags") the bits in task::rseq_event_mask are meaningless and just extra work in terms of setting them individually. Aside of that the only relevant point where an event has to be raised is context switch. Neither the CPU nor MM CID can change without going through a context switch. Collapse them all into a single boolean which simplifies the code a lot and remove the pointless invocations which have been sprinkled all over the place for no value. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084306.336978188@linutronix.de
2025-10-07coredump: fix core_pattern input validationChristian Brauner1-1/+1
In be1e0283021e ("coredump: don't pointlessly check and spew warnings") we tried to fix input validation so it only happens during a write to core_pattern. This would avoid needlessly logging a lot of warnings during a read operation. However the logic accidently got inverted in this commit. Fix it so the input validation only happens on write and is skipped on read. Fixes: be1e0283021e ("coredump: don't pointlessly check and spew warnings") Fixes: 16195d2c7dd2 ("coredump: validate socket name as it is written") Reviewed-by: Jan Kara <jack@suse.cz> Reported-by: Yu Watanabe <watanabe.yu@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-02Merge tag 'mm-stable-2025-10-01-19-00' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - "mm, swap: improve cluster scan strategy" from Kairui Song improves performance and reduces the failure rate of swap cluster allocation - "support large align and nid in Rust allocators" from Vitaly Wool permits Rust allocators to set NUMA node and large alignment when perforning slub and vmalloc reallocs - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend DAMOS_STAT's handling of the DAMON operations sets for virtual address spaces for ops-level DAMOS filters - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren Baghdasaryan reduces mmap_lock contention during reads of /proc/pid/maps - "mm/mincore: minor clean up for swap cache checking" from Kairui Song performs some cleanup in the swap code - "mm: vm_normal_page*() improvements" from David Hildenbrand provides code cleanup in the pagemap code - "add persistent huge zero folio support" from Pankaj Raghav provides a block layer speedup by optionalls making the huge_zero_pagepersistent, instead of releasing it when its refcount falls to zero - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to the recently added Kexec Handover feature - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo Stoakes turns mm_struct.flags into a bitmap. To end the constant struggle with space shortage on 32-bit conflicting with 64-bit's needs - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap code - "selftests/mm: Fix false positives and skip unsupported tests" from Donet Tom fixes a few things in our selftests code - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised" from David Hildenbrand "allows individual processes to opt-out of THP=always into THP=madvise, without affecting other workloads on the system". It's a long story - the [1/N] changelog spells out the considerations - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on the memdesc project. Please see https://kernelnewbies.org/MatthewWilcox/Memdescs and https://blogs.oracle.com/linux/post/introducing-memdesc - "Tiny optimization for large read operations" from Chi Zhiling improves the efficiency of the pagecache read path - "Better split_huge_page_test result check" from Zi Yan improves our folio splitting selftest code - "test that rmap behaves as expected" from Wei Yang adds some rmap selftests - "remove write_cache_pages()" from Christoph Hellwig removes that function and converts its two remaining callers - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD selftests issues - "introduce kernel file mapped folios" from Boris Burkov introduces the concept of "kernel file pages". Using these permits btrfs to account its metadata pages to the root cgroup, rather than to the cgroups of random inappropriate tasks - "mm/pageblock: improve readability of some pageblock handling" from Wei Yang provides some readability improvements to the page allocator code - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON to understand arm32 highmem - "tools: testing: Use existing atomic.h for vma/maple tests" from Brendan Jackman performs some code cleanups and deduplication under tools/testing/ - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes a couple of 32-bit issues in tools/testing/radix-tree.c - "kasan: unify kasan_enabled() and remove arch-specific implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific initialization code into a common arch-neutral implementation - "mm: remove zpool" from Johannes Weiner removes zspool - an indirection layer which now only redirects to a single thing (zsmalloc) - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a couple of cleanups in the fork code - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of adjustments at various nth_page() callsites, eventually permitting the removal of that undesirable helper function - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun creates a KASAN read-only mode for ARM, using that architecture's memory tagging feature. It is felt that a read-only mode KASAN is suitable for use in production systems rather than debug-only - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does some tidying in the hugetlb folio allocation code - "mm: establish const-correctness for pointer parameters" from Max Kellermann makes quite a number of the MM API functions more accurate about the constness of their arguments. This was getting in the way of subsystems (in this case CEPH) when they attempt to improving their own const/non-const accuracy - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of code sites which were confused over when to use free_pages() vs __free_pages() - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the mapletree code accessible to Rust. Required by nouveau and by its forthcoming successor: the new Rust Nova driver - "selftests/mm: split_huge_page_test: split_pte_mapped_thp improvements" from David Hildenbrand adds a fix and some cleanups to the thp selftesting code - "mm, swap: introduce swap table as swap cache (phase I)" from Chris Li and Kairui Song is the first step along the path to implementing "swap tables" - a new approach to swap allocation and state tracking which is expected to yield speed and space improvements. This patchset itself yields a 5-20% performance benefit in some situations - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc layer to clean up the ptdesc code a little - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some issues in our 5-level pagetable selftesting code - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan addresses a couple of minor issues in relatively new memory allocation profiling feature - "Small cleanups" from Matthew Wilcox has a few cleanups in preparation for more memdesc work - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from Quanmin Yan makes some changes to DAMON in furtherance of supporting arm highmem - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad Anjum adds that compiler check to selftests code and fixes the fallout, by removing dead code - "Improvements to Victim Process Thawing and OOM Reaper Traversal Order" from zhongjinji makes a number of improvements in the OOM killer: mainly thawing a more appropriate group of victim threads so they can release resources - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park is a bunch of small and unrelated fixups for DAMON - "mm/damon: define and use DAMON initialization check function" from SeongJae Park implement reliability and maintainability improvements to a recently-added bug fix - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from SeongJae Park provides additional transparency to userspace clients of the DAMON_STAT information - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes some constraints on khubepaged's collapsing of anon VMAs. It also increases the success rate of MADV_COLLAPSE against an anon vma - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()" from Lorenzo Stoakes moves us further towards removal of file_operations.mmap(). This patchset concentrates upon clearing up the treatment of stacked filesystems - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau provides some fixes and improvements to mlock's tracking of large folios. /proc/meminfo's "Mlocked" field became more accurate - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from Donet Tom fixes several user-visible KSM stats inaccuracies across forks and adds selftest code to verify these counters - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses some potential but presently benign issues in KSM's mm_slot handling * tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits) mm: swap: check for stable address space before operating on the VMA mm: convert folio_page() back to a macro mm/khugepaged: use start_addr/addr for improved readability hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list alloc_tag: fix boot failure due to NULL pointer dereference mm: silence data-race in update_hiwater_rss mm/memory-failure: don't select MEMORY_ISOLATION mm/khugepaged: remove definition of struct khugepaged_mm_slot mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL hugetlb: increase number of reserving hugepages via cmdline selftests/mm: add fork inheritance test for ksm_merging_pages counter mm/ksm: fix incorrect KSM counter handling in mm_struct during fork drivers/base/node: fix double free in register_one_node() mm: remove PMD alignment constraint in execmem_vmalloc() mm/memory_hotplug: fix typo 'esecially' -> 'especially' mm/rmap: improve mlock tracking for large folios mm/filemap: map entire large folio faultaround mm/fault: try to map the entire file folio in finish_fault() mm/rmap: mlock large folios in try_to_unmap_one() mm/rmap: fix a mlock race condition in folio_referenced_one() ...
2025-09-29Merge tag 'execve-v6.18-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull execve updates from Kees Cook: - binfmt_elf: preserve original ELF e_flags for core dumps (Svetlana Parfenova) - exec: Fix incorrect type for ret (Xichao Zhao) - binfmt_elf: Replace offsetof() with struct_size() in fill_note_info() (Xichao Zhao) * tag 'execve-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: binfmt_elf: preserve original ELF e_flags for core dumps binfmt_elf: Replace offsetof() with struct_size() in fill_note_info() exec: Fix incorrect type for ret
2025-09-13mm: update coredump logic to correctly use bitmap mm flagsLorenzo Stoakes1-1/+1
The coredump logic is slightly different from other users in that it both stores mm flags and additionally sets and gets using masks. Since the MMF_DUMPABLE_* flags must remain as they are for uABI reasons, and of course these are within the first 32-bits of the flags, it is reasonable to provide access to these in the same fashion so this logic can all still keep working as it has been. Therefore, introduce coredump-specific helpers __mm_flags_get_dumpable() and __mm_flags_set_mask_dumpable() for this purpose, and update all core dump users of mm flags to use these. [lorenzo.stoakes@oracle.com: abstract set_mask_bits() invocation to mm_types.h to satisfy ARC] Link: https://lkml.kernel.org/r/0e7ad263-1ff7-446d-81fe-97cff9c0e7ed@lucifer.local Link: https://lkml.kernel.org/r/2a5075f7e3c5b367d988178c79a3063d12ee53a9.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Christian Brauner <brauner@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-25exec: Fix incorrect type for retXichao Zhao1-1/+1
In the setup_arg_pages(), ret is declared as an unsigned long. The ret might take a negative value. Therefore, its type should be changed to int. Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20250825073609.219855-1-zhao.xichao@vivo.com Signed-off-by: Kees Cook <kees@kernel.org>
2025-08-21coredump: don't pointlessly check and spew warningsChristian Brauner1-1/+1
When a write happens it doesn't make sense to check perform checks on the input. Skip them. Whether a fixes tag is licensed is a bit of a gray area here but I'll add one for the socket validation part I added recently. Link: https://lore.kernel.org/20250821-moosbedeckt-denunziant-7908663f3563@brauner Fixes: 16195d2c7dd2 ("coredump: validate socket name as it is written") Reported-by: Brad Spengler <brad.spengler@opensrcsec.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-31Merge tag 'mm-stable-2025-07-30-15-25' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quot