kernel/linux.git/fs/proc/base.c, branch v7.2-rc1

Merge tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-06-21T20:20:19+00:00

Pull non-MM updates from Andrew Morton: - "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen) Fix a taskstats TGID aggregation bug where fields added in the TGID query path were not preserved after thread exit, and adds a kselftest covering the regression. - "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko) Improve lib/tests/string_helpers_kunit.c a little - "lib/base64: decode fixes" (Josh Law) Address minor issues in lib/base64.c - "selftests/filelock: Make output more kselftestish" (Mark Brown) Make the output from the ofdlocks test a bit easier for tooling to work with. Also ignore the generated file - "uaccess: unify inline vs outline copy_{from,to}_user() selection" (Yury Norov) Simplify the usercopy code by removing the selectability of inlining copy_{from,to}_user(). - "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang) Fix a number of possible issues in the ocfs2 xattr code - "lib and lib/cmdline enhancements" (Dmitry Antipov) Provide additional robustness checking in the cmdline handling code and its in-kernel testing and selftests - "cleanup the RAID6 P/Q library" (Christoph Hellwig) Clean up the RAID6 P/Q library to match the recent updates to the RAID 5 XOR library and other CRC/crypto libraries - "ocfs2: harden inode validators against forged metadata" (Michael Bommarito) Add three structural checks to OCFS2 dinode validation so malformed on-disk fields are rejected before ocfs2_populate_inode() copies them into the in-core inode - "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike Rapoport) Clean up the lib/raid code by using kmalloc() in more places * tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits) ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits lib: interval_tree_test: validate benchmark parameters ocfs2: avoid moving extents to occupied clusters treewide: fix transposed "sign" typos and update spelling.txt ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec fat: reject BPB volumes whose data area starts beyond total sectors selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems lib/test_firmware: allocate the configured into_buf size fs: efs: remove unneeded debug prints checkpatch: cuppress warnings when Reported-by: is followed by Link: MAINTAINERS: add Alexander as a kcov reviewer mailmap: update Alexander Sverdlin's Email addresses fs: fat: inode: replace sprintf() with scnprintf() ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release() ocfs2/dlm: require a ref for locking_state debugfs open ocfs2: reject FITRIM ranges shorter than a cluster ocfs2: validate fast symlink target during inode read ocfs2: add journal NULL check in ocfs2_checkpoint_inode() ...

Merge tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2026-06-14T22:45:31+00:00

Pull dcache updates from Al Viro: - d_alloc_parallel() API change (Neil's with my changes) - NORCU fixes - Reorganization and simplification of dentry eviction logic - Simplifying rcu_read_lock() scopes in fs/dcache.c - Secondary roots work - getting rid of NFS fake root dentries and dealing with remaining shrink_dcache_for_umount() and shrink_dentry_list() races - making cursors NORCU (surprisingly easy) * tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (22 commits) make cursors NORCU nfs: get rid of fake root dentries wind ->s_roots via ->d_sib instead of ->d_hash shrink_dentry_tree(): unify the calls of shrink_dentry_list() shrinking rcu_read_lock() scope in d_alloc_parallel() d_walk(): shrink rcu_read_lock() scope document dentry_kill() adjust calling conventions of lock_for_kill(), fold __dentry_kill() into dentry_kill() Document rcu_read_lock() use in select_collect2() Shift rcu_read_{,un}lock() inside fast_dput() simplify safety for lock_for_kill() slowpath fold lock_for_kill() and __dentry_kill() into common helper fold lock_for_kill() into shrink_kill() shrink_dentry_list(): start with removing from shrink list d_prune_aliases(): make sure to skip NORCU aliases kill d_dispose_if_unused() make to_shrink_list() return whether it has moved dentry to list select_collect(): ignore dentries on shrink lists if they have positive refcounts find_acceptable_alias(): skip NORCU aliases with zero refcount fix a race between d_find_any_alias() and final dput() of NORCU dentries ...

Merge tag 'vfs-7.2-rc1.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-06-14T22:37:58+00:00

Pull procfs updates from Christian Brauner: - Revamp fs/filesystems.c The file was a mess with a hand-rolled linked list in desperate need of a cleanup. The filesystems list is now RCU-ified, /proc files can be marked permanent from outside fs/proc/, and the string emitted when reading /proc/filesystems is pre-generated and cached instead of pointer-chasing and printfing entry by entry on every read. The file is read frequently because libselinux reads it and is linked into numerous frequently used programs (even ones you would not suspect, like sed!). Scalability also improves since reference maintenance on open/close is bypassed. open+read+close cycle single-threaded (ops/s): before: 442732 after: 1063462 (+140%) open+read+close cycle with 20 processes (ops/s): before: 606177 after: 3300576 (+444%) A follow-up patch adds missing unlocks in some corner cases and tidies things up. - Relax the mount visibility check for subset=pid mounts When procfs is mounted with subset=pid, all static files become unavailable and only the dynamic pid information is accessible. In that case there is no point in imposing the full mount visibility restrictions on the mounter - everything that can be hidden in procfs is already inaccessible. These restrictions prevented procfs from being mounted inside rootless containers since almost all container implementations overmount parts of procfs to hide certain directories. As part of this /proc/self/net is only shown in subset=pid mounts for CAP_NET_ADMIN, reconfiguring subset=pid is rejected, the SB_I_USERNS_VISIBLE superblock flag is replaced with an FS_USERNS_MOUNT_RESTRICTED filesystem flag, fully visible mounts are recorded in a list, and the mount restrictions are finally documented. - Protect ptrace_may_access() with exec_update_lock in procfs Most uses of ptrace_may_access() in procfs should hold exec_update_lock to avoid TOCTOU issues with concurrent privileged execve() (like setuid binary execution). This fixes the easy cases - the owner and visibility checks and the FD link permission checks - with the gnarlier ones to follow later. * tag 'vfs-7.2-rc1.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: fix ups and tidy ups to /proc/filesystems caching proc: protect ptrace_may_access() with exec_update_lock (FD links) proc: protect ptrace_may_access() with exec_update_lock (part 1) docs: proc: add documentation about mount restrictions proc: handle subset=pid separately in userns visibility checks proc: prevent reconfiguring subset=pid proc: subset=pid: Show /proc/self/net only for CAP_NET_ADMIN fs: cache the string generated by reading /proc/filesystems sysfs: remove trivial sysfs_get_tree() wrapper fs: RCU-ify filesystems list fs: move SB_I_USERNS_VISIBLE to FS_USERNS_MOUNT_RESTRICTED proc: allow to mark /proc files permanent outside of fs/proc/ namespace: record fully visible mounts in list

Merge tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-06-14T22:29:45+00:00

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() ...

proc: protect ptrace_may_access() with exec_update_lock (FD links)

2026-06-05T08:00:55+00:00

proc_pid_get_link() and proc_pid_readlink() currently look up the task from the pid once, then do the ptrace access check on that task, then look up the task from the pid a second time to do the actual access. That's racy in several ways. To fix it, pass the task to the ->proc_get_link() handler, and instead of proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that looks up and locks the task, does the access check, and calls ->proc_get_link(). Fixes: 778c1144771f ("[PATCH] proc: Use sane permission checks on the /proc//fd/ symlinks") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Link: https://patch.msgid.link/20260518-procfs-lockfix-part1-v1-2-5c3d20e0ac33@google.com Signed-off-by: Christian Brauner (Amutable)

proc: protect ptrace_may_access() with exec_update_lock (part 1)

2026-06-05T08:00:55+00:00

Fix the easy cases where procfs currently calls ptrace_may_access() without exec_update_lock protection, where the fix is to simply add the extra lock or use mm_access(): - do_task_stat(): grab exec_update_lock - proc_pid_wchan(): grab exec_update_lock - proc_map_files_lookup(): use mm_access() instead of get_task_mm() - proc_map_files_readdir(): use mm_access() instead of get_task_mm() - proc_ns_get_link(): grab exec_update_lock - proc_ns_readlink(): grab exec_update_lock Fixes: f83ce3e6b02d ("proc: avoid information leaks to non-privileged processes") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Link: https://patch.msgid.link/20260518-procfs-lockfix-part1-v1-1-5c3d20e0ac33@google.com Signed-off-by: Christian Brauner (Amutable)

VFS: use wait_var_event for waiting in d_alloc_parallel()

2026-06-05T04:34:54+00:00

Parallel lookup starts with a call of d_alloc_parallel(). That primitive either returns a matching hashed dentry or allocates a new one in the in-lookup state and returns it to the caller. Once the caller is done with lookup, it indicates so either by call of d_{splice_alias,add}() or by call of d_done_lookup(); at that point dentry leaves the in-lookup state. If d_alloc_parallel() finds a matching in-lookup dentry, it must wait for that dentry to leave the in-lookup state, one way or another. Currently by supplying wait_queue_head to d_alloc_parallel(). If d_alloc_parallel() creates a new in-lookup dentry, the address of that wait_queue_head is stored in ->d_wait of new dentry and stays there while it's in the in-lookup; subsequent d_alloc_parallel() will wait on the queue found in the matching in-lookup dentry. Transition out of in-lookup state wakes waiters on that queue (if any). That works, but the calling conventions are inconvenient - the caller must supply wait_queue_head and make sure that it survives at least until the new in-lookup dentry leaves the in-lookup state. That amounts to boilerplate in the d_alloc_parallel() callers that are followed by a call of d_lookup_done() in the same function; in cases like nfs asynchronous unlink it gets worse than that. This patch changes d_alloc_parallel() to use wake_up_var_locked() to wake up waiters, and wait_var_event_spinlock() to wait. dentry->d_lock is used for synchronisation as it is already held and the relevant times. That eliminates the need of caller-supplied wait_queue_head, simplifying the calling conventions. Better yet, we only need one bit of information stored in dentry itself: whether there are any waiters to be woken up, and that can be easily stored in ->d_flags; ->d_wait goes away. The reason we need that bit (DCACHE_LOOKUP_WAITERS) is that with wait_var machinery the queues are shared with all kinds of stuff and there's no way tell if any of the waiters have anything to do with our dentry; most of the time none of them will be relevant, so we need to avoid the pointless wakeups. Another benefit of the new scheme comes from the fact that wakeups have to be done outside of write-side critical areas of ->i_dir_seq; with the old scheme we need to carry the value picked from ->d_wait from __d_lookup_unhash() to the place where we actually wake the waiters up. Now we can just leave DCACHE_LOOKUP_WAITERS in ->d_flags until we get to doing wakeups - that's done within the same ->d_lock scope, so we are fine; new bit is accessed only under ->d_lock and it's seen only on dentries with DCACHE_PAR_LOOKUP in ->d_flags. __d_lookup_unhash() no longer needs to re-init ->d_lru. That was previously shared (in a union) with ->d_wait but ->d_wait is now gone so it no longer corrupts ->d_lru. Co-developed-by: Al Viro # saner handling of flags Signed-off-by: NeilBrown Signed-off-by: Al Viro

proc: rewrite next_tgid()

2026-05-29T04:24:39+00:00

* deduplicate "iter.tgid += 1" line, Right now it is done once inside next_tgid() itself and second time inside "for" loop. * deduplicate next_tgid() call itself with different loop style: auto it = make_tgid_iter(); while (next_tgid(&it)) { ... } gcc seems to inline it twice: $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux add/remove: 0/1 grow/shrink: 1/0 up/down: 100/-245 (-145) Function old new delta proc_pid_readdir 531 631 +100 next_tgid 245 - -245 * make tgid_iter.pid_ns const it never changes during readdir anyway [akpm@linux-foundation.org: remove newline] Link: https://lore.kernel.org/20260422191745.435556-2-adobriyan@gmail.com Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

proc: add tgid_iter.pid_ns member

2026-05-29T04:24:38+00:00

next_tgid() accepts pid namespace as an argument, but it never changes during readdir (which would be unthinkable thing to do anyway). Move it inside iterator type and hide from direct usage. Link: https://lore.kernel.org/20260422191745.435556-1-adobriyan@gmail.com Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

proc: replace __get_free_page() with kmalloc()

2026-05-27T13:12:22+00:00

A few functions in fs/proc/base.c use __get_free_page() to allocate a temporary buffer. kmalloc() is a better API for such use and it also provides better scalability and more debugging possibilities. Replace use of __get_free_page() with kmalloc(). Signed-off-by: Mike Rapoport (Microsoft) Link: https://patch.msgid.link/20260523-b4-fs-v1-2-275e36a83f0e@kernel.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner (Amutable)