kernel/git/stable/linux.git/fs/notify, branch linux-6.12.y

fanotify: report full event length for FIONREAD

2026-09-14T11:32:26+00:00

[ Upstream commit 68615158c12de36220446dfea5cfdf9ba6c19690 ] fanotify_ioctl(FIONREAD) reports the number of bytes available to read from the event queue. It currently accounts only FAN_EVENT_METADATA_LEN for each queued event. That underestimates events that carry additional information records, such as FAN_REPORT_DFID_NAME events. A userspace program that uses FIONREAD to size its read buffer can receive a length that is smaller than the next event. Reading with that buffer then fails with -EINVAL, while a larger buffer succeeds and reports a larger metadata.event_len. Use fanotify_event_len() when summing queued events so FIONREAD includes all info records. Fixes: 5e469c830fdb ("fanotify: copy event fid info to user") Signed-off-by: Yichong Chen Link: https://patch.msgid.link/20260731021827.602479-1-chenyichong@uniontech.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

fsnotify: inotify: pass mark connector to fsnotify_recalc_mask()

2026-09-14T11:30:57+00:00

[ Upstream commit 4520b96b8136ba2465a3f4dc5c3fb8bdf3d92e4e ] fsnotify_recalc_mask() expects a plain struct fsnotify_mark_connector *, but inode->i_fsnotify_marks is an __rcu pointer. Use fsn_mark->connector instead to avoid sparse "different address spaces" warnings. Signed-off-by: Sun Jian Link: https://patch.msgid.link/20260214051217.1381363-1-sun.jian.kdev@gmail.com Signed-off-by: Jan Kara (cherry picked from commit 4520b96b8136ba2465a3f4dc5c3fb8bdf3d92e4e) Signed-off-by: Youngjae Kwon Signed-off-by: Sasha Levin

fsnotify: Fix stale object mask after concurrent mark updates

2026-09-14T11:30:57+00:00

[ Upstream commit e422777fdd4746de1109575c51e65038d4c5c1be ] When a mark gets a new event bit, fanotify and inotify may avoid recalculating the object mask if the cached aggregate already contains that bit. This is racy with a recalculation triggered by a concurrent update to another mark on the same connector. The concurrent scan can read the mark before the new bit is added, while the updater reads the old aggregate before that scan publishes its result. The updater then skips recalculation and the scan publishes a mask without the bit, leaving the object mask stale after both updates complete. This can be reproduced with two fanotify groups watching the same inode: one thread removes FAN_MODIFY from one existing mark while another thread adds FAN_MODIFY to the other mark. After both fanotify_mark() calls return, writes can fail to produce FAN_MODIFY for the group whose mark now contains the bit. This was reproduced on an unmodified v6.12.95 kernel. The equivalent inotify interleaving loses IN_MODIFY events. For normal fanotify additions, recalculate whenever the raw mark mask changes. The normal mask is not cleared asynchronously, so an unchanged addition cannot introduce missing interest. Always recalculate ignore-mask updates because FS_MODIFY handling may clear the ignore mask without taking mark->lock, making snapshot comparisons unreliable. Always recalculate after updating an existing inotify watch. Its replace path temporarily sets mark->mask to zero, so a concurrent scan can observe zero even when the old and final masks are equal. Assigning the replacement mask directly would avoid the transient zero, but existing-watch updates are infrequent, so unconditional recalculation is simpler. Link: https://lore.kernel.org/all/CACwKKmCZdiZDoFuYm6LZhQ=XvHPk0fNKH=X3LmoXMqakYqJaNw@mail.gmail.com/ Fixes: 63c882a05416 ("inotify: reimplement inotify using fsnotify") Fixes: 912ee3946c5e ("fanotify: do not call fanotify_update_object_mask in fanotify_add_mark") Cc: stable@vger.kernel.org # needs adjustments for <= 7.0 Suggested-by: Jan Kara Suggested-by: Amir Goldstein Signed-off-by: Youngjae Kwon Link: https://patch.msgid.link/20260802015801.2426818-1-yjkwon0026@snu.ac.kr Signed-off-by: Jan Kara (cherry picked from commit e422777fdd4746de1109575c51e65038d4c5c1be) [yjkwon0026: Resolve the inotify conflict by retaining the branch-native inode->i_fsnotify_marks argument to fsnotify_recalc_mask(). This tree lacks 4520b96b8136 ("fsnotify: inotify: pass mark connector to fsnotify_recalc_mask()"). The surrounding conditional is deleted by this patch, so that commit is not a prerequisite for this fix.] Signed-off-by: Youngjae Kwon Signed-off-by: Sasha Levin

fsnotify: opt-in for permission events at file open time

2026-08-23T12:22:46+00:00

[ Upstream commit a94204f4d48e28a711b7ed10399f749286c433e3 ] Legacy inotify/fanotify listeners can add watches for events on inode, parent or mount and expect to get events (e.g. FS_MODIFY) on files that were already open at the time of setting up the watches. fanotify permission events are typically used by Anti-malware sofware, that is watching the entire mount and it is not common to have more that one Anti-malware engine installed on a system. To reduce the overhead of the fsnotify_file_perm() hooks on every file access, relax the semantics of the legacy FAN_ACCESS_PERM event to generate events only if there were *any* permission event listeners on the filesystem at the time that the file was opened. The new semantic is implemented by extending the FMODE_NONOTIFY bit into two FMODE_NONOTIFY_* bits, that are used to store a mode for which of the events types to report. This is going to apply to the new fanotify pre-content events in order to reduce the cost of the new pre-content event vfs hooks. [Thanks to Bert Karwatzki for reporting a bug in this code with CONFIG_FANOTIFY_ACCESS_PERMISSIONS disabled] Suggested-by: Linus Torvalds Link: https://lore.kernel.org/linux-fsdevel/CAHk-=wj8L=mtcRTi=NECHMGfZQgXOp_uix1YVh04fEmrKaMnXA@mail.gmail.com/ Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://patch.msgid.link/5ea5f8e283d1edb55aa79c35187bfe344056af14.1731684329.git.josef@toxicpanda.com Stable-dep-of: db1856ea9196 ("binfmt_misc: restore write access when removing an entry") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

fsnotify, lsm: Decouple fsnotify from lsm

2026-08-23T12:22:46+00:00

[ Upstream commit 1cda52f1b4611f4daa9d89e69d9428fb4137dc3f ] Currently, fsnotify_open_perm() is called from security_file_open(). This is a a bit unexpected and creates otherwise unnecessary dependency of CONFIG_FANOTIFY_ACCESS_PERMISSIONS on CONFIG_SECURITY. Fix this by calling fsnotify_open_perm() directly. Signed-off-by: Song Liu Acked-by: Paul Moore Signed-off-by: Jan Kara Link: https://patch.msgid.link/20241013002248.3984442-1-song@kernel.org Stable-dep-of: db1856ea9196 ("binfmt_misc: restore write access when removing an entry") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

remove pointless includes of

2026-06-09T10:25:43+00:00

[ Upstream commit be5498cac2ddb112c5bd7433d5e834a1a2493427 ] some of those used to be needed, some had been cargo-culted for no reason... Reviewed-by: Christian Brauner Signed-off-by: Al Viro Stable-dep-of: ea5fe6a73ca5 ("net/handshake: Drain pending requests at net namespace exit") Signed-off-by: Sasha Levin

fsnotify: fix inode reference leak in fsnotify_recalc_mask()

2026-05-23T11:04:52+00:00

[ Upstream commit 4aca914ac152f5d055ddcb36704d1e539ac08977 ] fsnotify_recalc_mask() fails to handle the return value of __fsnotify_recalc_mask(), which may return an inode pointer that needs to be released via fsnotify_drop_object() when the connector's HAS_IREF flag transitions from set to cleared. This manifests as a hung task with the following call trace: INFO: task umount:1234 blocked for more than 120 seconds. Call Trace: __schedule schedule fsnotify_sb_delete generic_shutdown_super kill_anon_super cleanup_mnt task_work_run do_exit do_group_exit The race window that triggers the iref leak: Thread A (adding mark) Thread B (removing mark) ────────────────────── ──────────────────────── fsnotify_add_mark_locked(): fsnotify_add_mark_list(): spin_lock(conn->lock) add mark_B(evictable) to list spin_unlock(conn->lock) return /* ---- gap: no lock held ---- */ fsnotify_detach_mark(mark_A): spin_lock(mark_A->lock) clear ATTACHED flag on mark_A spin_unlock(mark_A->lock) fsnotify_put_mark(mark_A) fsnotify_recalc_mask(): spin_lock(conn->lock) __fsnotify_recalc_mask(): /* mark_A skipped: ATTACHED cleared */ /* only mark_B(evictable) remains */ want_iref = false has_iref = true /* not yet cleared */ -> HAS_IREF transitions true -> false -> returns inode pointer spin_unlock(conn->lock) /* BUG: return value discarded! * iput() and fsnotify_put_sb_watched_objects() * are never called */ Fix this by deferring the transition true -> false of HAS_IREF flag from fsnotify_recalc_mask() (Thread A) to fsnotify_put_mark() (thread B). Fixes: c3638b5b1374 ("fsnotify: allow adding an inode mark without pinning inode") Signed-off-by: Xin Yin Signed-off-by: Amir Goldstein Link: https://patch.msgid.link/CAOQ4uxiPsbHb0o5voUKyPFMvBsDkG914FYDcs4C5UpBMNm0Vcg@mail.gmail.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

fanotify: call fanotify_events_supported() before path_permission() and security_path_notify()

2026-05-23T11:04:35+00:00

[ Upstream commit 66052a768d4726a31e939b5ac902f2b0b452c8d5 ] The latter trigger LSM (e.g. SELinux) checks, which will log a denial when permission is denied, so it's better to do them after validity checks to avoid logging a denial when the operation would fail anyway. Fixes: 0b3b094ac9a7 ("fanotify: Disallow permission events for proc filesystem") Signed-off-by: Ondrej Mosnacek Reviewed-by: Amir Goldstein Reviewed-by: Paul Moore Link: https://patch.msgid.link/20260216150625.793013-3-omosnace@redhat.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

fdget(), trivial conversions

2026-05-23T11:04:35+00:00

[ Upstream commit 6348be02eead77bdd1562154ed6b3296ad3b3750 ] fdget() is the first thing done in scope, all matching fdput() are immediately followed by leaving the scope. Reviewed-by: Christian Brauner Signed-off-by: Al Viro Stable-dep-of: 66052a768d47 ("fanotify: call fanotify_events_supported() before path_permission() and security_path_notify()") Signed-off-by: Sasha Levin

fanotify: fix false positive on permission events

2026-05-14T13:29:21+00:00

commit 7746e3bd4cc19b5092e00d32d676e329bfcb6900 upstream. fsnotify_get_mark_safe() may return false for a mark on an unrelated group, which results in bypassing the permission check. Fix by skipping over detached marks that are not in the current group. CC: stable@vger.kernel.org Fixes: abc77577a669 ("fsnotify: Provide framework for dropping SRCU lock in ->handle_event") Signed-off-by: Miklos Szeredi Link: https://patch.msgid.link/20260410144950.156160-1-mszeredi@redhat.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman