From patchwork Tue Jul 30 08:54:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 13747073 Received: from mailout1.hostsharing.net (mailout1.hostsharing.net [83.223.95.204]) (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 31BA343152; Tue, 30 Jul 2024 08:54:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.95.204 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329698; cv=none; b=Ag9ekxlKp8FTKNUNHnVWh9OeaFKp3XzDlPprmDqcUClH/kgs2iLbbWXHGXrskMRGIDyHpPols5q8mur4Bfyw9wJaW9KrNSPmMpUzxK+36zPhhh4PATsH9FzxbfyWYx5K+yB7UDmjbhCpS79GyOK6UYA/C4wThQn+KkvMMxPuFhU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329698; c=relaxed/simple; bh=evmp6JIC0/O0Np7RtQdWKUhbbxAoESChjbkK9myxIVk=; h=Message-ID:From:Date:Subject:To:Cc; b=lMbPSuMOKLzJJ8yRONeZFhpsZJdEcUdpvP0R3JNDj6I/TL6akDXxPTFonY7LGPe5XQkOuwuFHeKQ5TV+8Z2Ilz4okIrPm0V4btrZjEHl0SXAOmEos4EC//08gr4ecmomJB6kUcAdiPMq/0w9sZe4I62OCbK07PZ5+oXt6PBQyHY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=pass smtp.mailfrom=wunner.de; arc=none smtp.client-ip=83.223.95.204 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wunner.de Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by mailout1.hostsharing.net (Postfix) with ESMTPS id E39131019178E; Tue, 30 Jul 2024 10:54:51 +0200 (CEST) Received: from localhost (unknown [89.246.108.87]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id B46C7603B5E6; Tue, 30 Jul 2024 10:54:51 +0200 (CEST) X-Mailbox-Line: From dd76a3196d5295fa7575bf149d890e647fbe0fd6 Mon Sep 17 00:00:00 2001 Message-ID: From: Lukas Wunner Date: Tue, 30 Jul 2024 10:54:51 +0200 Subject: [PATCH 5.15-stable 1/3] locking: Introduce __cleanup() based infrastructure To: Greg Kroah-Hartman , Sasha Levin Cc: stable@vger.kernel.org, linux-pci@vger.kernel.org, Keith Busch , Mika Westerberg , Bjorn Helgaas , Krzysztof Wilczynski , Ira Weiny , Peter Zijlstra Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: From: Peter Zijlstra commit 54da6a0924311c7cf5015533991e44fb8eb12773 upstream. Use __attribute__((__cleanup__(func))) to build: - simple auto-release pointers using __free() - 'classes' with constructor and destructor semantics for scope-based resource management. - lock guards based on the above classes. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Lukas Wunner Link: https://lkml.kernel.org/r/20230612093537.614161713%40infradead.org --- include/linux/cleanup.h | 171 ++++++++++++++++++++++++++++ include/linux/compiler-clang.h | 9 ++ include/linux/compiler_attributes.h | 6 + include/linux/device.h | 7 ++ include/linux/file.h | 6 + include/linux/irqflags.h | 7 ++ include/linux/mutex.h | 4 + include/linux/percpu.h | 4 + include/linux/preempt.h | 5 + include/linux/rcupdate.h | 3 + include/linux/rwsem.h | 8 ++ include/linux/sched/task.h | 2 + include/linux/slab.h | 4 + include/linux/spinlock.h | 31 +++++ include/linux/srcu.h | 5 + scripts/checkpatch.pl | 2 +- 16 files changed, 273 insertions(+), 1 deletion(-) create mode 100644 include/linux/cleanup.h diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h new file mode 100644 index 000000000000..53f1a7a932b0 --- /dev/null +++ b/include/linux/cleanup.h @@ -0,0 +1,171 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_GUARDS_H +#define __LINUX_GUARDS_H + +#include + +/* + * DEFINE_FREE(name, type, free): + * simple helper macro that defines the required wrapper for a __free() + * based cleanup function. @free is an expression using '_T' to access + * the variable. + * + * __free(name): + * variable attribute to add a scoped based cleanup to the variable. + * + * no_free_ptr(var): + * like a non-atomic xchg(var, NULL), such that the cleanup function will + * be inhibited -- provided it sanely deals with a NULL value. + * + * return_ptr(p): + * returns p while inhibiting the __free(). + * + * Ex. + * + * DEFINE_FREE(kfree, void *, if (_T) kfree(_T)) + * + * struct obj *p __free(kfree) = kmalloc(...); + * if (!p) + * return NULL; + * + * if (!init_obj(p)) + * return NULL; + * + * return_ptr(p); + */ + +#define DEFINE_FREE(_name, _type, _free) \ + static inline void __free_##_name(void *p) { _type _T = *(_type *)p; _free; } + +#define __free(_name) __cleanup(__free_##_name) + +#define no_free_ptr(p) \ + ({ __auto_type __ptr = (p); (p) = NULL; __ptr; }) + +#define return_ptr(p) return no_free_ptr(p) + + +/* + * DEFINE_CLASS(name, type, exit, init, init_args...): + * helper to define the destructor and constructor for a type. + * @exit is an expression using '_T' -- similar to FREE above. + * @init is an expression in @init_args resulting in @type + * + * EXTEND_CLASS(name, ext, init, init_args...): + * extends class @name to @name@ext with the new constructor + * + * CLASS(name, var)(args...): + * declare the variable @var as an instance of the named class + * + * Ex. + * + * DEFINE_CLASS(fdget, struct fd, fdput(_T), fdget(fd), int fd) + * + * CLASS(fdget, f)(fd); + * if (!f.file) + * return -EBADF; + * + * // use 'f' without concern + */ + +#define DEFINE_CLASS(_name, _type, _exit, _init, _init_args...) \ +typedef _type class_##_name##_t; \ +static inline void class_##_name##_destructor(_type *p) \ +{ _type _T = *p; _exit; } \ +static inline _type class_##_name##_constructor(_init_args) \ +{ _type t = _init; return t; } + +#define EXTEND_CLASS(_name, ext, _init, _init_args...) \ +typedef class_##_name##_t class_##_name##ext##_t; \ +static inline void class_##_name##ext##_destructor(class_##_name##_t *p)\ +{ class_##_name##_destructor(p); } \ +static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ +{ class_##_name##_t t = _init; return t; } + +#define CLASS(_name, var) \ + class_##_name##_t var __cleanup(class_##_name##_destructor) = \ + class_##_name##_constructor + + +/* + * DEFINE_GUARD(name, type, lock, unlock): + * trivial wrapper around DEFINE_CLASS() above specifically + * for locks. + * + * guard(name): + * an anonymous instance of the (guard) class + * + * scoped_guard (name, args...) { }: + * similar to CLASS(name, scope)(args), except the variable (with the + * explicit name 'scope') is declard in a for-loop such that its scope is + * bound to the next (compound) statement. + * + */ + +#define DEFINE_GUARD(_name, _type, _lock, _unlock) \ + DEFINE_CLASS(_name, _type, _unlock, ({ _lock; _T; }), _type _T) + +#define guard(_name) \ + CLASS(_name, __UNIQUE_ID(guard)) + +#define scoped_guard(_name, args...) \ + for (CLASS(_name, scope)(args), \ + *done = NULL; !done; done = (void *)1) + +/* + * Additional helper macros for generating lock guards with types, either for + * locks that don't have a native type (eg. RCU, preempt) or those that need a + * 'fat' pointer (eg. spin_lock_irqsave). + * + * DEFINE_LOCK_GUARD_0(name, lock, unlock, ...) + * DEFINE_LOCK_GUARD_1(name, type, lock, unlock, ...) + * + * will result in the following type: + * + * typedef struct { + * type *lock; // 'type := void' for the _0 variant + * __VA_ARGS__; + * } class_##name##_t; + * + * As above, both _lock and _unlock are statements, except this time '_T' will + * be a pointer to the above struct. + */ + +#define __DEFINE_UNLOCK_GUARD(_name, _type, _unlock, ...) \ +typedef struct { \ + _type *lock; \ + __VA_ARGS__; \ +} class_##_name##_t; \ + \ +static inline void class_##_name##_destructor(class_##_name##_t *_T) \ +{ \ + if (_T->lock) { _unlock; } \ +} + + +#define __DEFINE_LOCK_GUARD_1(_name, _type, _lock) \ +static inline class_##_name##_t class_##_name##_constructor(_type *l) \ +{ \ + class_##_name##_t _t = { .lock = l }, *_T = &_t; \ + _lock; \ + return _t; \ +} + +#define __DEFINE_LOCK_GUARD_0(_name, _lock) \ +static inline class_##_name##_t class_##_name##_constructor(void) \ +{ \ + class_##_name##_t _t = { .lock = (void*)1 }, \ + *_T __maybe_unused = &_t; \ + _lock; \ + return _t; \ +} + +#define DEFINE_LOCK_GUARD_1(_name, _type, _lock, _unlock, ...) \ +__DEFINE_UNLOCK_GUARD(_name, _type, _unlock, __VA_ARGS__) \ +__DEFINE_LOCK_GUARD_1(_name, _type, _lock) + +#define DEFINE_LOCK_GUARD_0(_name, _lock, _unlock, ...) \ +__DEFINE_UNLOCK_GUARD(_name, void, _unlock, __VA_ARGS__) \ +__DEFINE_LOCK_GUARD_0(_name, _lock) + +#endif /* __LINUX_GUARDS_H */ diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 3c4de9b6c6e3..e75768ca8c18 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -5,6 +5,15 @@ /* Compiler specific definitions for Clang compiler */ +/* + * Clang prior to 17 is being silly and considers many __cleanup() variables + * as unused (because they are, their sole purpose is to go out of scope). + * + * https://reviews.llvm.org/D152180 + */ +#undef __cleanup +#define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func))) + /* same as gcc, this was present in clang-2.6 so we can assume it works * with any version that can compile the kernel */ diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index 932b8fd6f36f..5ee9e2aeab63 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -80,6 +80,12 @@ */ #define __cold __attribute__((__cold__)) +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-cleanup-variable-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#cleanup + */ +#define __cleanup(func) __attribute__((__cleanup__(func))) + /* * Note the long name. * diff --git a/include/linux/device.h b/include/linux/device.h index 3e04bd84f126..3826d3a0c625 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -30,6 +30,7 @@ #include #include #include +#include #include struct device; @@ -822,6 +823,9 @@ void device_unregister(struct device *dev); void device_initialize(struct device *dev); int __must_check device_add(struct device *dev); void device_del(struct device *dev); + +DEFINE_FREE(device_del, struct device *, if (_T) device_del(_T)) + int device_for_each_child(struct device *dev, void *data, int (*fn)(struct device *dev, void *data)); int device_for_each_child_reverse(struct device *dev, void *data, @@ -950,6 +954,9 @@ extern int (*platform_notify_remove)(struct device *dev); */ struct device *get_device(struct device *dev); void put_device(struct device *dev); + +DEFINE_FREE(put_device, struct device *, if (_T) put_device(_T)) + bool kill_device(struct device *dev); #ifdef CONFIG_DEVTMPFS diff --git a/include/linux/file.h b/include/linux/file.h index 51e830b4fe3a..6726240b9279 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -10,6 +10,7 @@ #include #include #include +#include struct file; @@ -82,6 +83,8 @@ static inline void fdput_pos(struct fd f) fdput(f); } +DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd) + extern int f_dupfd(unsigned int from, struct file *file, unsigned flags); extern int replace_fd(unsigned fd, struct file *file, unsigned flags); extern void set_close_on_exec(unsigned int fd, int flag); @@ -90,6 +93,9 @@ extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile); extern int get_unused_fd_flags(unsigned flags); extern void put_unused_fd(unsigned int fd); +DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), + get_unused_fd_flags(flags), unsigned flags) + extern void fd_install(unsigned int fd, struct file *file); extern int __receive_fd(struct file *file, int __user *ufd, diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 37738ec87de3..c4288c7ae613 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -13,6 +13,7 @@ #define _LINUX_TRACE_IRQFLAGS_H #include +#include #include #include @@ -260,4 +261,10 @@ extern void warn_bogus_irq_restore(void); #define irqs_disabled_flags(flags) raw_irqs_disabled_flags(flags) +DEFINE_LOCK_GUARD_0(irq, local_irq_disable(), local_irq_enable()) +DEFINE_LOCK_GUARD_0(irqsave, + local_irq_save(_T->flags), + local_irq_restore(_T->flags), + unsigned long flags) + #endif diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 9ef01b9d2456..5b5630e58407 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -19,6 +19,7 @@ #include #include #include +#include struct device; @@ -246,4 +247,7 @@ extern void mutex_unlock(struct mutex *lock); extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); +DEFINE_GUARD(mutex, struct mutex *, mutex_lock(_T), mutex_unlock(_T)) +DEFINE_FREE(mutex, struct mutex *, if (_T) mutex_unlock(_T)) + #endif /* __LINUX_MUTEX_H */ diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 5e76af742c80..c9a84532bb79 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -9,6 +9,7 @@ #include #include #include +#include #include @@ -134,6 +135,9 @@ extern void __init setup_per_cpu_areas(void); extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp); extern void __percpu *__alloc_percpu(size_t size, size_t align); extern void free_percpu(void __percpu *__pdata); + +DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T)) + extern phys_addr_t per_cpu_ptr_to_phys(void *addr); #define alloc_percpu_gfp(type, gfp) \ diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 9c4534a69a8f..36c4233742a1 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -8,6 +8,7 @@ */ #include +#include #include /* @@ -431,4 +432,8 @@ static inline void migrate_enable(void) { } #endif /* CONFIG_SMP */ +DEFINE_LOCK_GUARD_0(preempt, preempt_disable(), preempt_enable()) +DEFINE_LOCK_GUARD_0(preempt_notrace, preempt_disable_notrace(), preempt_enable_notrace()) +DEFINE_LOCK_GUARD_0(migrate, migrate_disable(), migrate_enable()) + #endif /* __LINUX_PREEMPT_H */ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d908af591733..b45cf762ed1e 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -1057,4 +1058,6 @@ rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f) extern int rcu_expedited; extern int rcu_normal; +DEFINE_LOCK_GUARD_0(rcu, rcu_read_lock(), rcu_read_unlock()) + #endif /* __LINUX_RCUPDATE_H */ diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 352c6127cb90..458a0c92cc68 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -16,6 +16,7 @@ #include #include #include +#include #ifdef CONFIG_DEBUG_LOCK_ALLOC # define __RWSEM_DEP_MAP_INIT(lockname) \ @@ -202,6 +203,13 @@ extern void up_read(struct rw_semaphore *sem); */ extern void up_write(struct rw_semaphore *sem); +DEFINE_GUARD(rwsem_read, struct rw_semaphore *, down_read(_T), up_read(_T)) +DEFINE_GUARD(rwsem_write, struct rw_semaphore *, down_write(_T), up_write(_T)) + +DEFINE_FREE(up_read, struct rw_semaphore *, if (_T) up_read(_T)) +DEFINE_FREE(up_write, struct rw_semaphore *, if (_T) up_write(_T)) + + /* * downgrade write lock to read lock */ diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 0c2d00809915..fa9f79ac4bac 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -141,6 +141,8 @@ static inline void put_task_struct(struct task_struct *t) __put_task_struct(t); } +DEFINE_FREE(put_task, struct task_struct *, if (_T) put_task_struct(_T)) + static inline void put_task_struct_many(struct task_struct *t, int nr) { if (refcount_sub_and_test(nr, &t->usage)) diff --git a/include/linux/slab.h b/include/linux/slab.h index 083f3ce550bc..78a471aa8145 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -17,6 +17,7 @@ #include #include #include +#include /* @@ -186,6 +187,9 @@ void kfree(const void *); void kfree_sensitive(const void *); size_t __ksize(const void *); size_t ksize(const void *); + +DEFINE_FREE(kfree, void *, if (_T) kfree(_T)) + #ifdef CONFIG_PRINTK bool kmem_valid_obj(void *object); void kmem_dump_obj(void *object); diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 45310ea1b1d7..44ac0897c26c 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -61,6 +61,7 @@ #include #include #include +#include #include #include @@ -506,4 +507,34 @@ int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *lock_mask, void free_bucket_spinlocks(spinlock_t *locks); +DEFINE_LOCK_GUARD_1(raw_spinlock, raw_spinlock_t, + raw_spin_lock(_T->lock), + raw_spin_unlock(_T->lock)) + +DEFINE_LOCK_GUARD_1(raw_spinlock_nested, raw_spinlock_t, + raw_spin_lock_nested(_T->lock, SINGLE_DEPTH_NESTING), + raw_spin_unlock(_T->lock)) + +DEFINE_LOCK_GUARD_1(raw_spinlock_irq, raw_spinlock_t, + raw_spin_lock_irq(_T->lock), + raw_spin_unlock_irq(_T->lock)) + +DEFINE_LOCK_GUARD_1(raw_spinlock_irqsave, raw_spinlock_t, + raw_spin_lock_irqsave(_T->lock, _T->flags), + raw_spin_unlock_irqrestore(_T->lock, _T->flags), + unsigned long flags) + +DEFINE_LOCK_GUARD_1(spinlock, spinlock_t, + spin_lock(_T->lock), + spin_unlock(_T->lock)) + +DEFINE_LOCK_GUARD_1(spinlock_irq, spinlock_t, + spin_lock_irq(_T->lock), + spin_unlock_irq(_T->lock)) + +DEFINE_LOCK_GUARD_1(spinlock_irqsave, spinlock_t, + spin_lock_irqsave(_T->lock, _T->flags), + spin_unlock_irqrestore(_T->lock, _T->flags), + unsigned long flags) + #endif /* __LINUX_SPINLOCK_H */ diff --git a/include/linux/srcu.h b/include/linux/srcu.h index e6011a9975af..e94687215fbe 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -211,4 +211,9 @@ static inline void smp_mb__after_srcu_read_unlock(void) /* __srcu_read_unlock has smp_mb() internally so nothing to do here. */ } +DEFINE_LOCK_GUARD_1(srcu, struct srcu_struct, + _T->idx = srcu_read_lock(_T->lock), + srcu_read_unlock(_T->lock, _T->idx), + int idx) + #endif diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 88cb294dc447..b4fe18228805 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4895,7 +4895,7 @@ sub process { if|for|while|switch|return|case| volatile|__volatile__| __attribute__|format|__extension__| - asm|__asm__)$/x) + asm|__asm__|scoped_guard)$/x) { # cpp #define statements have non-optional spaces, ie # if there is a space between the name and the open From patchwork Tue Jul 30 08:54:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 13747077 Received: from mailout1.hostsharing.net (mailout1.hostsharing.net [83.223.95.204]) (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 0BB091922C1; Tue, 30 Jul 2024 08:57:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.95.204 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329834; cv=none; b=rNfKF2wIKQVaKWZJDcnSfXLAfeJkBEGSHp2TRRJOSLoXyTbTlKKMt0PytiIWOAk++PYcSujSoHowhMHOdFVZTHmMe0rB4xn35yC7SsjhYczCkmisI2dF0rwCVzH9AAX/p/NJ3yl49MfxxSIAzIYCb3LJ9P4OJXzu81iHHJct2ZY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329834; c=relaxed/simple; bh=YJKK4IVKDzljNLqWRBrWvNv4Hak/f8FkkzC+8NmoFYk=; h=Message-ID:In-Reply-To:References:From:Date:Subject:To:Cc; b=UfPJWc9XfHOw7rU2mGyXXqKres+IlxxknZ4dwXvRhAdEMMUxZRTx6g1cjlNilZ0z20PftlUGn4odC56Hk3f0Q8hNkXxDA3TlNtJVkoKZkyzRyo7qAUYkb7ufz67fmnm1pFEEm2nqpfg/+mUDNNjpSmkmNh7JHWVLL88UZHVhwhQ= ARC-Authentication-Results: i=1; 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Tue, 30 Jul 2024 10:57:08 +0200 (CEST) X-Mailbox-Line: From 59b16a6b13dbccacb6200d9e04c5ef1830a7311a Mon Sep 17 00:00:00 2001 Message-ID: <59b16a6b13dbccacb6200d9e04c5ef1830a7311a.1722329230.git.lukas@wunner.de> In-Reply-To: References: From: Lukas Wunner Date: Tue, 30 Jul 2024 10:54:52 +0200 Subject: [PATCH 5.15-stable 2/3] PCI: Introduce cleanup helper for device reference counts To: Greg Kroah-Hartman , Sasha Levin Cc: stable@vger.kernel.org, linux-pci@vger.kernel.org, Keith Busch , Mika Westerberg , Bjorn Helgaas , Krzysztof Wilczynski , Ira Weiny , Peter Zijlstra Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: From: Ira Weiny commit ced085ef369af7a2b6da962ec2fbd01339f60693 upstream. The "goto error" pattern is notorious for introducing subtle resource leaks. Use the new cleanup.h helpers for PCI device reference counts. Similar to the new put_device() cleanup helper, __free(put_device), define the same for PCI devices, __free(pci_dev_put). These helpers eliminate the need for "goto free;" patterns. For example, a 'struct pci_dev *' instance declared as: struct pci_dev *pdev __free(pci_dev_put) = NULL; ...will automatically call pci_dev_put() if @pdev is non-NULL when @pdev goes out of scope (automatic variable scope). If a function wants to invoke pci_dev_put() on error, but return @pdev on success, it can do: return no_free_ptr(pdev); ...or: return_ptr(pdev); For potential cleanup opportunity there are 587 open-coded calls to pci_dev_put() in the kernel with 65 instances within 10 lines of a goto statement with the CXL driver threatening to add another one. Cc: Bjorn Helgaas Signed-off-by: Ira Weiny Link: https://lore.kernel.org/r/20231220-cxl-cper-v5-8-1bb8a4ca2c7a@intel.com [djbw: rewrite changelog] Acked-by: Bjorn Helgaas Reviewed-by: Jonathan Cameron Acked-by: Ard Biesheuvel Signed-off-by: Dan Williams [lukas: drop DEFINE_GUARD() helper as pci_dev_lock() doesn't exist in v5.15] Signed-off-by: Lukas Wunner --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/pci.h b/include/linux/pci.h index 32805c3a37bb..20199983a283 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1122,6 +1122,7 @@ int pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge); u8 pci_common_swizzle(struct pci_dev *dev, u8 *pinp); struct pci_dev *pci_dev_get(struct pci_dev *dev); void pci_dev_put(struct pci_dev *dev); +DEFINE_FREE(pci_dev_put, struct pci_dev *, if (_T) pci_dev_put(_T)) void pci_remove_bus(struct pci_bus *b); void pci_stop_and_remove_bus_device(struct pci_dev *dev); void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev); From patchwork Tue Jul 30 08:54:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 13747078 Received: from mailout3.hostsharing.net (mailout3.hostsharing.net [176.9.242.54]) (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 BF1EA19415E; Tue, 30 Jul 2024 08:58:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=176.9.242.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329930; cv=none; b=Xwqvuy4u1+540waAduXMqVHsjXdnIx8Lk6awaz6MEjZ/NjW4G72rluy+j/DJ1scdEweAtpHS7pxM3wJW0eNwP+T8+SDxgMW1X1dFRXSkebm3Y9tOmnNisn4X1PsW6f8fqpM42pruVAgfOj2nhMPQKAiztO/BekZrYtUOKVSXxtE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722329930; c=relaxed/simple; bh=iEakntx8Bt2oH1h38v8aQqTliKryIlaVyKQl/fXR5BE=; h=Message-ID:In-Reply-To:References:From:Date:Subject:MIME-Version: Content-Type:To:Cc; b=GgmqnE64J8UUgrGNR5HGDLHvUoOcQCuT+9r1OesaRK9E3/XrJQ6BrKbVyp6FGiozMNiOPBM6GE3eVhnut/229Fgc9Jsfxz3+b2w5o3Fb7L8bE7/mhcgkk7fkuYmmyn3AxT84tpAnRFewJ/vwtKBN5JA/VmPj0LSPxIPfT+a7KmQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=pass smtp.mailfrom=wunner.de; arc=none smtp.client-ip=176.9.242.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wunner.de Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by mailout3.hostsharing.net (Postfix) with ESMTPS id 812CC10029ED4; Tue, 30 Jul 2024 10:58:45 +0200 (CEST) Received: from localhost (unknown [89.246.108.87]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 36697603B5E6; Tue, 30 Jul 2024 10:58:45 +0200 (CEST) X-Mailbox-Line: From d36c93b351fad08b503448e04714d35af844f7b9 Mon Sep 17 00:00:00 2001 Message-ID: In-Reply-To: References: From: Lukas Wunner Date: Tue, 30 Jul 2024 10:54:53 +0200 Subject: [PATCH 5.15-stable 3/3] PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: Greg Kroah-Hartman , Sasha Levin Cc: stable@vger.kernel.org, linux-pci@vger.kernel.org, Keith Busch , Mika Westerberg , Bjorn Helgaas , Krzysztof Wilczynski , Ira Weiny , Peter Zijlstra commit 11a1f4bc47362700fcbde717292158873fb847ed upstream. Keith reports a use-after-free when a DPC event occurs concurrently to hot-removal of the same portion of the hierarchy: The dpc_handler() awaits readiness of the secondary bus below the Downstream Port where the DPC event occurred. To do so, it polls the config space of the first child device on the secondary bus. If that child device is concurrently removed, accesses to its struct pci_dev cause the kernel to oops. That's because pci_bridge_wait_for_secondary_bus() neglects to hold a reference on the child device. Before v6.3, the function was only called on resume from system sleep or on runtime resume. Holding a reference wasn't necessary back then because the pciehp IRQ thread could never run concurrently. (On resume from system sleep, IRQs are not enabled until after the resume_noirq phase. And runtime resume is always awaited before a PCI device is removed.) However starting with v6.3, pci_bridge_wait_for_secondary_bus() is also called on a DPC event. Commit 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset"), which introduced that, failed to appreciate that pci_bridge_wait_for_secondary_bus() now needs to hold a reference on the child device because dpc_handler() and pciehp may indeed run concurrently. The commit was backported to v5.10+ stable kernels, so that's the oldest one affected. Add the missing reference acquisition. Abridged stack trace: BUG: unable to handle page fault for address: 00000000091400c0 CPU: 15 PID: 2464 Comm: irq/53-pcie-dpc 6.9.0 RIP: pci_bus_read_config_dword+0x17/0x50 pci_dev_wait() pci_bridge_wait_for_secondary_bus() dpc_reset_link() pcie_do_recovery() dpc_handler() Fixes: 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset") Closes: https://lore.kernel.org/r/20240612181625.3604512-3-kbusch@meta.com/ Link: https://lore.kernel.org/linux-pci/8e4bcd4116fd94f592f2bf2749f168099c480ddf.1718707743.git.lukas@wunner.de Reported-by: Keith Busch Tested-by: Keith Busch Signed-off-by: Lukas Wunner Signed-off-by: Krzysztof Wilczyński Reviewed-by: Keith Busch Reviewed-by: Mika Westerberg Cc: stable@vger.kernel.org # v5.10+ --- drivers/pci/pci.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 67216f4ea215..a041d5c8370d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4915,7 +4915,7 @@ static int pci_bus_max_d3cold_delay(const struct pci_bus *bus) int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type, int timeout) { - struct pci_dev *child; + struct pci_dev *child __free(pci_dev_put) = NULL; int delay; if (pci_dev_is_disconnected(dev)) @@ -4944,8 +4944,8 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type, return 0; } - child = list_first_entry(&dev->subordinate->devices, struct pci_dev, - bus_list); + child = pci_dev_get(list_first_entry(&dev->subordinate->devices, + struct pci_dev, bus_list)); up_read(&pci_bus_sem); /*