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>
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>
Currently, vmlinux BTF is unconditionally sorted during the build phase. The function btf_find_by_name_kind executes the binary search branch, so find_bpffs_btf_enums can be optimized by using btf_find_by_name_kind. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20260109130003.3313716-10-dolinux.peng@gmail.com
object creation goes through the normal VFS paths or approximation
thereof (user_path_create()/done_path_create() in case of bpf_obj_do_pin(),
open-coded simple_{start,done}_creating() in bpf_iter_link_pin_kernel()
at mount time), removals go entirely through the normal VFS paths (and
->unlink() is simple_unlink() there).
Enough to have bpf_dentry_finalize() use d_make_persistent() instead
of dget() and we are done.
Convert bpf_iter_link_pin_kernel() to simple_{start,done}_creating(),
while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When unpinning a BPF hash table (htab or htab_lru) that contains internal
structures (timer, workqueue, or task_work) in its values, a BUG warning
is triggered:
BUG: sleeping function called from invalid context at kernel/bpf/hashtab.c:244
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 14, name: ksoftirqd/0
...
The issue arises from the interaction between BPF object unpinning and
RCU callback mechanisms:
1. BPF object unpinning uses ->free_inode() which schedules cleanup via
call_rcu(), deferring the actual freeing to an RCU callback that
executes within the RCU_SOFTIRQ context.
2. During cleanup of hash tables containing internal structures,
htab_map_free_internal_structs() is invoked, which includes
cond_resched() or cond_resched_rcu() calls to yield the CPU during
potentially long operations.
However, cond_resched() or cond_resched_rcu() cannot be safely called from
atomic RCU softirq context, leading to the BUG warning when attempting
to reschedule.
Fix this by changing from ->free_inode() to ->destroy_inode() and rename
bpf_free_inode() to bpf_destroy_inode() for BPF objects (prog, map, link).
This allows direct inode freeing without RCU callback scheduling,
avoiding the invalid context warning.
Reported-by: Le Chen <tom2cat@sjtu.edu.cn>
Closes: https://lore.kernel.org/all/1444123482.1827743.1750996347470.JavaMail.zimbra@sjtu.edu.cn/
Fixes: 68134668c17f ("bpf: Add map side support for bpf timers.")
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: KaFai Wan <kafai.wan@linux.dev>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251008102628.808045-2-kafai.wan@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull vfs async directory updates from Christian Brauner:
"This contains further preparatory changes for the asynchronous directory
locking scheme:
- Add lookup_one_positive_killable() which allows overlayfs to
perform lookup that won't block on a fatal signal
- Unify the mount idmap handling in struct renamedata as a rename can
only happen within a single mount
- Introduce kern_path_parent() for audit which sets the path to the
parent and returns a dentry for the target without holding any
locks on return
- Rename kern_path_locked() as it is only used to prepare for the
removal of an object from the filesystem:
kern_path_locked() => start_removing_path()
kern_path_create() => start_creating_path()
user_path_create() => start_creating_user_path()
user_path_locked_at() => start_removing_user_path_at()
done_path_create() => end_creating_path()
NA => end_removing_path()"
* tag 'vfs-6.18-rc1.async' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
debugfs: rename start_creating() to debugfs_start_creating()
VFS: rename kern_path_locked() and related functions.
VFS/audit: introduce kern_path_parent() for audit
VFS: unify old_mnt_idmap and new_mnt_idmap in renamedata
VFS: discard err2 in filename_create()
VFS/ovl: add lookup_one_positive_killable()
kern_path_locked() is now only used to prepare for removing an object from the filesystem (and that is the only credible reason for wanting a positive locked dentry). Thus it corresponds to kern_path_create() and so should have a corresponding name. Unfortunately the name "kern_path_create" is somewhat misleading as it doesn't actually create anything. The recently added simple_start_creating() provides a better pattern I believe. The "start" can be matched with "end" to bracket the creating or removing. So this patch changes names: kern_path_locked -> start_removing_path kern_path_create -> start_creating_path user_path_create -> start_creating_user_path user_path_locked_at -> start_removing_user_path_at done_path_create -> end_creating_path and also introduces end_removing_path() which is identical to end_creating_path(). __start_removing_path (which was __kern_path_locked) is enhanced to call mnt_want_write() for consistency with the start_creating_path(). Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: NeilBrown <neil@brown.name> Signed-off-by: Christian Brauner <brauner@kernel.org>
generic_delete_inode() is rather misleading for what the routine is doing. inode_just_drop() should be much clearer. The new naming is inconsistent with generic_drop_inode(), so rename that one as well with inode_ as the suffix. No functional changes. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g. on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns. For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.
This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes. Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.
This lookup-after-mkdir requires that the directory remains locked to
avoid races. Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.
To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
NULL - the directory was created and no other dentry was used
ERR_PTR() - an error occurred
non-NULL - this other dentry was spliced in
This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations. Subsequent patches will make
further changes to some file-systems to return a correct dentry.
Not all filesystems reliably result in a positive hashed dentry:
- NFS, cifs, hostfs will sometimes need to perform a lookup of
the name to get inode information. Races could result in this
returning something different. Note that this lookup is
non-atomic which is what we are trying to avoid. Placing the
lookup in filesystem code means it only happens when the filesystem
has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
operation ensures that lookup will be called to correctly populate
the dentry. This could be fixed but I don't think it is important
to any of the users of vfs_mkdir() which look at the dentry.
The recommendation to use
d_drop();d_splice_alias()
is ugly but fits with current practice. A planned future patch will
change this.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>