From nobody Sun Feb 8 14:41:49 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B359120E313; Mon, 3 Mar 2025 18:52:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741027924; cv=none; b=D6WgAuDERO1eqv7cFw/z48fzC7paLI/rrwaL2jzwCM/BIUucpBGn6vbqSUq14zj7B+lY36cvx89C8IUHJ5v+37YkFwpD9woNsSe3IW8S/YoNUegIWctypwbcb8A/DsGP9/MqxHLV55O9w6sMbHoszTAtLc+RuvfoYoJmZ89yvO4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741027924; c=relaxed/simple; bh=o/qmX6hSgRoymOE1dWMcvLTwjwRGpOCvn8rPyegWrZM=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=J0LIstR07ZgijCfqS+yq174KvDpuc8v9KJ469PsVgPh1Jh2WpOVHLQ3zogx9C5UsyrX6WrFy0X2b9RvbbHS+Sk7GeIe4BAo/TKMoezzHsdgaaeFq6oh1ryqafmc1XmSbUQ+F/gsD+HWF/w2xs5e4Ufdwq5xQNLNz0iy1RTK6du0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=gWcpkIGY; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=hA6GGIAv; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="gWcpkIGY"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="hA6GGIAv" Date: Mon, 03 Mar 2025 18:51:52 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1741027915; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TGeQYAabFLDEOsh+5xx1WnuyM7t4dWXnTfPHS1MGtgo=; b=gWcpkIGYiWQOQSuT1i3++lIzJZx9iq0yDSPSQxZXGey0AK2FB7VhcwMv1KjB+ycR0vN/0m PcMSEgN9rUGzdOSIFijwhqowwHC0RrB+5KqPnbVFlQd53coYjMEgvRKIv0WQt0qbHYlxkb Szf4zQVIQmf9mh6A2pnTqIVVZNSmr4/Jvly9BhpQjgfG/eY5VL13x5nxse9RLlNdm/yvqj rYPvtaSYuCmPdB5K0lJohkv7PO7x/+0B2QFANluVzmjyAEpy2Xy5A12+OySr5BlQ++0VCx 12yMrnc3xIv24YpdDxLc5QysPFbOp8GXk0/LA3AnestT4TNXbtDdg2mBxYYASA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1741027915; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TGeQYAabFLDEOsh+5xx1WnuyM7t4dWXnTfPHS1MGtgo=; b=hA6GGIAvYoxhoDMCJ8FGZzV7BMxFVRL2/MxVUcu+vRprAt7n+55hAI5dtrhWO9h4i2GS8M 42lunAcBBk8Ma6DA== From: "tip-bot2 for Mitchell Levy" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] rust: lockdep: Use Pin for all LockClassKey usages Cc: Benno Lossin , Boqun Feng , Mitchell Levy , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20250207-rust-lockdep-v4-2-7a50a7e88656@gmail.com> References: <20250207-rust-lockdep-v4-2-7a50a7e88656@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <174102791234.14745.9352511071714022288.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the locking/core branch of tip: Commit-ID: 3b5b307cf84ca3a73abe797df31e0efe897411a9 Gitweb: https://git.kernel.org/tip/3b5b307cf84ca3a73abe797df31e0efe8= 97411a9 Author: Mitchell Levy AuthorDate: Fri, 07 Feb 2025 16:39:09 -08:00 Committer: Boqun Feng CommitterDate: Tue, 25 Feb 2025 08:53:08 -08:00 rust: lockdep: Use Pin for all LockClassKey usages Reintroduce dynamically-allocated LockClassKeys such that they are automatically (de)registered. Require that all usages of LockClassKeys ensure that they are Pin'd. Currently, only `'static` LockClassKeys are supported, so Pin is redundant. However, it is intended that dynamically-allocated LockClassKeys will eventually be supported, so using Pin from the outset will make that change simpler. Closes: https://github.com/Rust-for-Linux/linux/issues/1102 Suggested-by: Benno Lossin Suggested-by: Boqun Feng Signed-off-by: Mitchell Levy Reviewed-by: Benno Lossin Signed-off-by: Boqun Feng Link: https://lore.kernel.org/r/20250207-rust-lockdep-v4-2-7a50a7e88656@gma= il.com --- rust/helpers/helpers.c | 1 +- rust/helpers/sync.c | 13 +++++++- rust/kernel/sync.rs | 57 ++++++++++++++++++++++++++++++-- rust/kernel/sync/condvar.rs | 5 +-- rust/kernel/sync/lock.rs | 4 +- rust/kernel/sync/lock/global.rs | 5 +-- rust/kernel/sync/poll.rs | 2 +- rust/kernel/workqueue.rs | 2 +- 8 files changed, 77 insertions(+), 12 deletions(-) create mode 100644 rust/helpers/sync.c diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 0640b7e..4c1a10a 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -30,6 +30,7 @@ #include "signal.c" #include "slab.c" #include "spinlock.c" +#include "sync.c" #include "task.c" #include "uaccess.c" #include "vmalloc.c" diff --git a/rust/helpers/sync.c b/rust/helpers/sync.c new file mode 100644 index 0000000..ff7e68b --- /dev/null +++ b/rust/helpers/sync.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_lockdep_register_key(struct lock_class_key *k) +{ + lockdep_register_key(k); +} + +void rust_helper_lockdep_unregister_key(struct lock_class_key *k) +{ + lockdep_unregister_key(k); +} diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index 16eab91..4104bc2 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -5,6 +5,8 @@ //! This module contains the kernel APIs related to synchronisation that h= ave been ported or //! wrapped for usage by Rust code in the kernel. =20 +use crate::pin_init; +use crate::prelude::*; use crate::types::Opaque; =20 mod arc; @@ -23,15 +25,64 @@ pub use locked_by::LockedBy; =20 /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`. #[repr(transparent)] -pub struct LockClassKey(Opaque); +#[pin_data(PinnedDrop)] +pub struct LockClassKey { + #[pin] + inner: Opaque, +} =20 // SAFETY: `bindings::lock_class_key` is designed to be used concurrently = from multiple threads and // provides its own synchronization. unsafe impl Sync for LockClassKey {} =20 impl LockClassKey { + /// Initializes a dynamically allocated lock class key. In the common = case of using a + /// statically allocated lock class key, the static_lock_class! macro = should be used instead. + /// + /// # Example + /// ``` + /// # use kernel::{c_str, stack_pin_init}; + /// # use kernel::alloc::KBox; + /// # use kernel::types::ForeignOwnable; + /// # use kernel::sync::{LockClassKey, SpinLock}; + /// + /// let key =3D KBox::pin_init(LockClassKey::new_dynamic(), GFP_KERNEL= )?; + /// let key_ptr =3D key.into_foreign(); + /// + /// { + /// stack_pin_init!(let num: SpinLock =3D SpinLock::new( + /// 0, + /// c_str!("my_spinlock"), + /// // SAFETY: `key_ptr` is returned by the above `into_foreig= n()`, whose + /// // `from_foreign()` has not yet been called. + /// unsafe { > as ForeignOwnable>::borr= ow(key_ptr) } + /// )); + /// } + /// + /// // SAFETY: We dropped `num`, the only use of the key, so the resul= t of the previous + /// // `borrow` has also been dropped. Thus, it's safe to use from_for= eign. + /// unsafe { drop(> as ForeignOwnable>::from_fo= reign(key_ptr)) }; + /// + /// # Ok::<(), Error>(()) + /// ``` + pub fn new_dynamic() -> impl PinInit { + pin_init!(Self { + // SAFETY: lockdep_register_key expects an uninitialized block= of memory + inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_re= gister_key(slot) }) + }) + } + pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { - self.0.get() + self.inner.get() + } +} + +#[pinned_drop] +impl PinnedDrop for LockClassKey { + fn drop(self: Pin<&mut Self>) { + // SAFETY: self.as_ptr was registered with lockdep and self is pin= ned, so the address + // hasn't changed. Thus, it's safe to pass to unregister. + unsafe { bindings::lockdep_unregister_key(self.as_ptr()) } } } =20 @@ -44,7 +95,7 @@ macro_rules! static_lock_class { // SAFETY: lockdep expects uninitialized memory when it's hand= ed a statically allocated // lock_class_key unsafe { ::core::mem::MaybeUninit::uninit().assume_init() }; - &CLASS + $crate::prelude::Pin::static_ref(&CLASS) }}; } =20 diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index 5c1e546..fbf68ad 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -17,8 +17,7 @@ use crate::{ time::Jiffies, types::Opaque, }; -use core::marker::PhantomPinned; -use core::ptr; +use core::{marker::PhantomPinned, pin::Pin, ptr}; use macros::pin_data; =20 /// Creates a [`CondVar`] initialiser with the given name and a newly-crea= ted lock class. @@ -103,7 +102,7 @@ unsafe impl Sync for CondVar {} =20 impl CondVar { /// Constructs a new condvar initialiser. - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl Pi= nInit { + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> im= pl PinInit { pin_init!(Self { _pin: PhantomPinned, // SAFETY: `slot` is valid while the closure is called and bot= h `name` and `key` have diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index f53e87d..360a10a 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -12,7 +12,7 @@ use crate::{ str::CStr, types::{NotThreadSafe, Opaque, ScopeGuard}, }; -use core::{cell::UnsafeCell, marker::PhantomPinned}; +use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin}; use macros::pin_data; =20 pub mod mutex; @@ -129,7 +129,7 @@ unsafe impl Sync for Lock= {} =20 impl Lock { /// Constructs a new lock initialiser. - pub fn new(t: T, name: &'static CStr, key: &'static LockClassKey) -> i= mpl PinInit { + pub fn new(t: T, name: &'static CStr, key: Pin<&'static LockClassKey>)= -> impl PinInit { pin_init!(Self { data: UnsafeCell::new(t), _pin: PhantomPinned, diff --git a/rust/kernel/sync/lock/global.rs b/rust/kernel/sync/lock/global= .rs index 480ee72..d65f94b 100644 --- a/rust/kernel/sync/lock/global.rs +++ b/rust/kernel/sync/lock/global.rs @@ -13,6 +13,7 @@ use crate::{ use core::{ cell::UnsafeCell, marker::{PhantomData, PhantomPinned}, + pin::Pin, }; =20 /// Trait implemented for marker types for global locks. @@ -26,7 +27,7 @@ pub trait GlobalLockBackend { /// The backend used for this global lock. type Backend: Backend + 'static; /// The class for this global lock. - fn get_lock_class() -> &'static LockClassKey; + fn get_lock_class() -> Pin<&'static LockClassKey>; } =20 /// Type used for global locks. @@ -270,7 +271,7 @@ macro_rules! global_lock { type Item =3D $valuety; type Backend =3D $crate::global_lock_inner!(backend $kind); =20 - fn get_lock_class() -> &'static $crate::sync::LockClassKey { + fn get_lock_class() -> Pin<&'static $crate::sync::LockClassKey= > { $crate::static_lock_class!() } } diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs index d5f1715..c4934f8 100644 --- a/rust/kernel/sync/poll.rs +++ b/rust/kernel/sync/poll.rs @@ -89,7 +89,7 @@ pub struct PollCondVar { =20 impl PollCondVar { /// Constructs a new condvar initialiser. - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl Pi= nInit { + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> im= pl PinInit { pin_init!(Self { inner <- CondVar::new(name, key), }) diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 0cd100d..6b6f3ad 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -369,7 +369,7 @@ unsafe impl Sync for Work {} impl Work { /// Creates a new instance of [`Work`]. #[inline] - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl Pi= nInit + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> im= pl PinInit where T: WorkItem, {