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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, anders.roxell@linaro.org,
	andreyknvl@google.com, arnd@arndb.de, dvyukov@google.com,
	dwindsor@gmail.com, elena.reshetova@intel.com, elver@google.com,
	glider@google.com, gregkh@linuxfoundation.org,
	jasowang@redhat.com, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, mst@redhat.com, rostedt@goodmis.org,
	stern@rowland.harvard.edu, torvalds@linux-foundation.org
Subject: [patch 56/86] kcov: remote coverage support
Date: Wed, 04 Dec 2019 16:52:43 -0800
Message-ID: <20191205005243.mM4_zD5YD%akpm@linux-foundation.org> (raw)
In-Reply-To: <20191204164858.fe4ed8886e34ad9f3b34ea00@linux-foundation.org>

From: Andrey Konovalov <andreyknvl@google.com>
Subject: kcov: remote coverage support

Patch series " kcov: collect coverage from usb and vhost", v3.

This patchset extends kcov to allow collecting coverage from backgound
kernel threads.  This extension requires custom annotations for each of
the places where coverage collection is desired.  This patchset implements
this for hub events in the USB subsystem and for vhost workers.  See the
first patch description for details about the kcov extension.  The other
two patches apply this kcov extension to USB and vhost.

Examples of other subsystems that might potentially benefit from this when
custom annotations are added (the list is based on process_one_work()
callers for bugs recently reported by syzbot):
1. fs: writeback wb_workfn() worker,
2. net: addrconf_dad_work()/addrconf_verify_work() workers,
3. net: neigh_periodic_work() worker,
4. net/p9: p9_write_work()/p9_read_work() workers,
5. block: blk_mq_run_work_fn() worker.

These patches have been used to enable coverage-guided USB fuzzing with
syzkaller for the last few years, see the details here:

https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md

This patchset has been pushed to the public Linux kernel Gerrit instance:

https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1524


This patch (of 3):

Add background thread coverage collection ability to kcov.

With KCOV_ENABLE coverage is collected only for syscalls that are issued
from the current process.  With KCOV_REMOTE_ENABLE it's possible to
collect coverage for arbitrary parts of the kernel code, provided that
those parts are annotated with kcov_remote_start()/kcov_remote_stop().

This allows to collect coverage from two types of kernel background
threads: the global ones, that are spawned during kernel boot in a limited
number of instances (e.g.  one USB hub_event() worker thread is spawned
per USB HCD); and the local ones, that are spawned when a user interacts
with some kernel interface (e.g.  vhost workers).

To enable collecting coverage from a global background thread, a unique
global handle must be assigned and passed to the corresponding
kcov_remote_start() call.  Then a userspace process can pass a list of
such handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field of
the kcov_remote_arg struct.  This will attach the used kcov device to the
code sections, that are referenced by those handles.

Since there might be many local background threads spawned from different
userspace processes, we can't use a single global handle per annotation. 
Instead, the userspace process passes a non-zero handle through the
common_handle field of the kcov_remote_arg struct.  This common handle
gets saved to the kcov_handle field in the current task_struct and needs
to be passed to the newly spawned threads via custom annotations.  Those
threads should in turn be annotated with
kcov_remote_start()/kcov_remote_stop().

Internally kcov stores handles as u64 integers.  The top byte of a handle
is used to denote the id of a subsystem that this handle belongs to, and
the lower 4 bytes are used to denote the id of a thread instance within
that subsystem.  A reserved value 0 is used as a subsystem id for common
handles as they don't belong to a particular subsystem.  The bytes 4-7 are
currently reserved and must be zero.  In the future the number of bytes
used for the subsystem or handle ids might be increased.

When a particular userspace process collects coverage by via a common
handle, kcov will collect coverage for each code section that is annotated
to use the common handle obtained as kcov_handle from the current
task_struct.  However non common handles allow to collect coverage
selectively from different subsystems.

Link: http://lkml.kernel.org/r/e90e315426a384207edbec1d6aa89e43008e4caf.1572366574.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/dev-tools/kcov.rst |  129 ++++++
 include/linux/kcov.h             |   23 +
 include/linux/sched.h            |    8 
 include/uapi/linux/kcov.h        |   28 +
 kernel/kcov.c                    |  547 +++++++++++++++++++++++++++--
 5 files changed, 700 insertions(+), 35 deletions(-)

--- a/Documentation/dev-tools/kcov.rst~kcov-remote-coverage-support
+++ a/Documentation/dev-tools/kcov.rst
@@ -34,6 +34,7 @@ Profiling data will only become accessib
 
 Coverage collection
 -------------------
+
 The following program demonstrates coverage collection from within a test
 program using kcov:
 
@@ -128,6 +129,7 @@ only need to enable coverage (disable ha
 
 Comparison operands collection
 ------------------------------
+
 Comparison operands collection is similar to coverage collection:
 
 .. code-block:: c
@@ -202,3 +204,130 @@ Comparison operands collection is simila
 
 Note that the kcov modes (coverage collection or comparison operands) are
 mutually exclusive.
+
+Remote coverage collection
+--------------------------
+
+With KCOV_ENABLE coverage is collected only for syscalls that are issued
+from the current process. With KCOV_REMOTE_ENABLE it's possible to collect
+coverage for arbitrary parts of the kernel code, provided that those parts
+are annotated with kcov_remote_start()/kcov_remote_stop().
+
+This allows to collect coverage from two types of kernel background
+threads: the global ones, that are spawned during kernel boot in a limited
+number of instances (e.g. one USB hub_event() worker thread is spawned per
+USB HCD); and the local ones, that are spawned when a user interacts with
+some kernel interface (e.g. vhost workers).
+
+To enable collecting coverage from a global background thread, a unique
+global handle must be assigned and passed to the corresponding
+kcov_remote_start() call. Then a userspace process can pass a list of such
+handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field of the
+kcov_remote_arg struct. This will attach the used kcov device to the code
+sections, that are referenced by those handles.
+
+Since there might be many local background threads spawned from different
+userspace processes, we can't use a single global handle per annotation.
+Instead, the userspace process passes a non-zero handle through the
+common_handle field of the kcov_remote_arg struct. This common handle gets
+saved to the kcov_handle field in the current task_struct and needs to be
+passed to the newly spawned threads via custom annotations. Those threads
+should in turn be annotated with kcov_remote_start()/kcov_remote_stop().
+
+Internally kcov stores handles as u64 integers. The top byte of a handle
+is used to denote the id of a subsystem that this handle belongs to, and
+the lower 4 bytes are used to denote the id of a thread instance within
+that subsystem. A reserved value 0 is used as a subsystem id for common
+handles as they don't belong to a particular subsystem. The bytes 4-7 are
+currently reserved and must be zero. In the future the number of bytes
+used for the subsystem or handle ids might be increased.
+
+When a particular userspace proccess collects coverage by via a common
+handle, kcov will collect coverage for each code section that is annotated
+to use the common handle obtained as kcov_handle from the current
+task_struct. However non common handles allow to collect coverage
+selectively from different subsystems.
+
+.. code-block:: c
+
+    struct kcov_remote_arg {
+	unsigned	trace_mode;
+	unsigned	area_size;
+	unsigned	num_handles;
+	uint64_t	common_handle;
+	uint64_t	handles[0];
+    };
+
+    #define KCOV_INIT_TRACE			_IOR('c', 1, unsigned long)
+    #define KCOV_DISABLE			_IO('c', 101)
+    #define KCOV_REMOTE_ENABLE		_IOW('c', 102, struct kcov_remote_arg)
+
+    #define COVER_SIZE	(64 << 10)
+
+    #define KCOV_TRACE_PC	0
+
+    #define KCOV_SUBSYSTEM_COMMON	(0x00ull << 56)
+    #define KCOV_SUBSYSTEM_USB	(0x01ull << 56)
+
+    #define KCOV_SUBSYSTEM_MASK	(0xffull << 56)
+    #define KCOV_INSTANCE_MASK	(0xffffffffull)
+
+    static inline __u64 kcov_remote_handle(__u64 subsys, __u64 inst)
+    {
+	if (subsys & ~KCOV_SUBSYSTEM_MASK || inst & ~KCOV_INSTANCE_MASK)
+		return 0;
+	return subsys | inst;
+    }
+
+    #define KCOV_COMMON_ID	0x42
+    #define KCOV_USB_BUS_NUM	1
+
+    int main(int argc, char **argv)
+    {
+	int fd;
+	unsigned long *cover, n, i;
+	struct kcov_remote_arg *arg;
+
+	fd = open("/sys/kernel/debug/kcov", O_RDWR);
+	if (fd == -1)
+		perror("open"), exit(1);
+	if (ioctl(fd, KCOV_INIT_TRACE, COVER_SIZE))
+		perror("ioctl"), exit(1);
+	cover = (unsigned long*)mmap(NULL, COVER_SIZE * sizeof(unsigned long),
+				     PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if ((void*)cover == MAP_FAILED)
+		perror("mmap"), exit(1);
+
+	/* Enable coverage collection via common handle and from USB bus #1. */
+	arg = calloc(1, sizeof(*arg) + sizeof(uint64_t));
+	if (!arg)
+		perror("calloc"), exit(1);
+	arg->trace_mode = KCOV_TRACE_PC;
+	arg->area_size = COVER_SIZE;
+	arg->num_handles = 1;
+	arg->common_handle = kcov_remote_handle(KCOV_SUBSYSTEM_COMMON,
+							KCOV_COMMON_ID);
+	arg->handles[0] = kcov_remote_handle(KCOV_SUBSYSTEM_USB,
+						KCOV_USB_BUS_NUM);
+	if (ioctl(fd, KCOV_REMOTE_ENABLE, arg))
+		perror("ioctl"), free(arg), exit(1);
+	free(arg);
+
+	/*
+	 * Here the user needs to trigger execution of a kernel code section
+	 * that is either annotated with the common handle, or to trigger some
+	 * activity on USB bus #1.
+	 */
+	sleep(2);
+
+	n = __atomic_load_n(&cover[0], __ATOMIC_RELAXED);
+	for (i = 0; i < n; i++)
+		printf("0x%lx\n", cover[i + 1]);
+	if (ioctl(fd, KCOV_DISABLE, 0))
+		perror("ioctl"), exit(1);
+	if (munmap(cover, COVER_SIZE * sizeof(unsigned long)))
+		perror("munmap"), exit(1);
+	if (close(fd))
+		perror("close"), exit(1);
+	return 0;
+    }
--- a/include/linux/kcov.h~kcov-remote-coverage-support
+++ a/include/linux/kcov.h
@@ -37,12 +37,35 @@ do {						\
 	(t)->kcov_mode &= ~KCOV_IN_CTXSW;	\
 } while (0)
 
+/* See Documentation/dev-tools/kcov.rst for usage details. */
+void kcov_remote_start(u64 handle);
+void kcov_remote_stop(void);
+u64 kcov_common_handle(void);
+
+static inline void kcov_remote_start_common(u64 id)
+{
+	kcov_remote_start(kcov_remote_handle(KCOV_SUBSYSTEM_COMMON, id));
+}
+
+static inline void kcov_remote_start_usb(u64 id)
+{
+	kcov_remote_start(kcov_remote_handle(KCOV_SUBSYSTEM_USB, id));
+}
+
 #else
 
 static inline void kcov_task_init(struct task_struct *t) {}
 static inline void kcov_task_exit(struct task_struct *t) {}
 static inline void kcov_prepare_switch(struct task_struct *t) {}
 static inline void kcov_finish_switch(struct task_struct *t) {}
+static inline void kcov_remote_start(u64 handle) {}
+static inline void kcov_remote_stop(void) {}
+static inline u64 kcov_common_handle(void)
+{
+	return 0;
+}
+static inline void kcov_remote_start_common(u64 id) {}
+static inline void kcov_remote_start_usb(u64 id) {}
 
 #endif /* CONFIG_KCOV */
 #endif /* _LINUX_KCOV_H */
--- a/include/linux/sched.h~kcov-remote-coverage-support
+++ a/include/linux/sched.h
@@ -1210,6 +1210,8 @@ struct task_struct {
 #endif /* CONFIG_TRACING */
 
 #ifdef CONFIG_KCOV
+	/* See kernel/kcov.c for more details. */
+
 	/* Coverage collection mode enabled for this task (0 if disabled): */
 	unsigned int			kcov_mode;
 
@@ -1221,6 +1223,12 @@ struct task_struct {
 
 	/* KCOV descriptor wired with this task or NULL: */
 	struct kcov			*kcov;
+
+	/* KCOV common handle for remote coverage collection: */
+	u64				kcov_handle;
+
+	/* KCOV sequence number: */
+	int				kcov_sequence;
 #endif
 
 #ifdef CONFIG_MEMCG
--- a/include/uapi/linux/kcov.h~kcov-remote-coverage-support
+++ a/include/uapi/linux/kcov.h
@@ -4,9 +4,24 @@
 
 #include <linux/types.h>
 
+/*
+ * Argument for KCOV_REMOTE_ENABLE ioctl, see Documentation/dev-tools/kcov.rst
+ * and the comment before kcov_remote_start() for usage details.
+ */
+struct kcov_remote_arg {
+	unsigned int	trace_mode;	/* KCOV_TRACE_PC or KCOV_TRACE_CMP */
+	unsigned int	area_size;	/* Length of coverage buffer in words */
+	unsigned int	num_handles;	/* Size of handles array */
+	__u64		common_handle;
+	__u64		handles[0];
+};
+
+#define KCOV_REMOTE_MAX_HANDLES		0x100
+
 #define KCOV_INIT_TRACE			_IOR('c', 1, unsigned long)
 #define KCOV_ENABLE			_IO('c', 100)
 #define KCOV_DISABLE			_IO('c', 101)
+#define KCOV_REMOTE_ENABLE		_IOW('c', 102, struct kcov_remote_arg)
 
 enum {
 	/*
@@ -32,4 +47,17 @@ enum {
 #define KCOV_CMP_SIZE(n)        ((n) << 1)
 #define KCOV_CMP_MASK           KCOV_CMP_SIZE(3)
 
+#define KCOV_SUBSYSTEM_COMMON	(0x00ull << 56)
+#define KCOV_SUBSYSTEM_USB	(0x01ull << 56)
+
+#define KCOV_SUBSYSTEM_MASK	(0xffull << 56)
+#define KCOV_INSTANCE_MASK	(0xffffffffull)
+
+static inline __u64 kcov_remote_handle(__u64 subsys, __u64 inst)
+{
+	if (subsys & ~KCOV_SUBSYSTEM_MASK || inst & ~KCOV_INSTANCE_MASK)
+		return 0;
+	return subsys | inst;
+}
+
 #endif /* _LINUX_KCOV_IOCTLS_H */
--- a/kernel/kcov.c~kcov-remote-coverage-support
+++ a/kernel/kcov.c
@@ -9,6 +9,7 @@
 #include <linux/types.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/hashtable.h>
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/preempt.h>
@@ -21,8 +22,11 @@
 #include <linux/uaccess.h>
 #include <linux/kcov.h>
 #include <linux/refcount.h>
+#include <linux/log2.h>
 #include <asm/setup.h>
 
+#define kcov_debug(fmt, ...) pr_debug("%s: " fmt, __func__, ##__VA_ARGS__)
+
 /* Number of 64-bit words written per one comparison: */
 #define KCOV_WORDS_PER_CMP 4
 
@@ -44,19 +48,100 @@ struct kcov {
 	 * Reference counter. We keep one for:
 	 *  - opened file descriptor
 	 *  - task with enabled coverage (we can't unwire it from another task)
+	 *  - each code section for remote coverage collection
 	 */
 	refcount_t		refcount;
 	/* The lock protects mode, size, area and t. */
 	spinlock_t		lock;
 	enum kcov_mode		mode;
-	/* Size of arena (in long's for KCOV_MODE_TRACE). */
-	unsigned		size;
+	/* Size of arena (in long's). */
+	unsigned int		size;
 	/* Coverage buffer shared with user space. */
 	void			*area;
 	/* Task for which we collect coverage, or NULL. */
 	struct task_struct	*t;
+	/* Collecting coverage from remote (background) threads. */
+	bool			remote;
+	/* Size of remote area (in long's). */
+	unsigned int		remote_size;
+	/*
+	 * Sequence is incremented each time kcov is reenabled, used by
+	 * kcov_remote_stop(), see the comment there.
+	 */
+	int			sequence;
 };
 
+struct kcov_remote_area {
+	struct list_head	list;
+	unsigned int		size;
+};
+
+struct kcov_remote {
+	u64			handle;
+	struct kcov		*kcov;
+	struct hlist_node	hnode;
+};
+
+static DEFINE_SPINLOCK(kcov_remote_lock);
+static DEFINE_HASHTABLE(kcov_remote_map, 4);
+static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas);
+
+/* Must be called with kcov_remote_lock locked. */
+static struct kcov_remote *kcov_remote_find(u64 handle)
+{
+	struct kcov_remote *remote;
+
+	hash_for_each_possible(kcov_remote_map, remote, hnode, handle) {
+		if (remote->handle == handle)
+			return remote;
+	}
+	return NULL;
+}
+
+static struct kcov_remote *kcov_remote_add(struct kcov *kcov, u64 handle)
+{
+	struct kcov_remote *remote;
+
+	if (kcov_remote_find(handle))
+		return ERR_PTR(-EEXIST);
+	remote = kmalloc(sizeof(*remote), GFP_ATOMIC);
+	if (!remote)
+		return ERR_PTR(-ENOMEM);
+	remote->handle = handle;
+	remote->kcov = kcov;
+	hash_add(kcov_remote_map, &remote->hnode, handle);
+	return remote;
+}
+
+/* Must be called with kcov_remote_lock locked. */
+static struct kcov_remote_area *kcov_remote_area_get(unsigned int size)
+{
+	struct kcov_remote_area *area;
+	struct list_head *pos;
+
+	kcov_debug("size = %u\n", size);
+	list_for_each(pos, &kcov_remote_areas) {
+		area = list_entry(pos, struct kcov_remote_area, list);
+		if (area->size == size) {
+			list_del(&area->list);
+			kcov_debug("rv = %px\n", area);
+			return area;
+		}
+	}
+	kcov_debug("rv = NULL\n");
+	return NULL;
+}
+
+/* Must be called with kcov_remote_lock locked. */
+static void kcov_remote_area_put(struct kcov_remote_area *area,
+					unsigned int size)
+{
+	kcov_debug("area = %px, size = %u\n", area, size);
+	INIT_LIST_HEAD(&area->list);
+	area->size = size;
+	list_add(&area->list, &kcov_remote_areas);
+}
+
 static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
 {
 	unsigned int mode;
@@ -73,7 +158,7 @@ static notrace bool check_kcov_mode(enum
 	 * in_interrupt() returns false (e.g. preempt_schedule_irq()).
 	 * READ_ONCE()/barrier() effectively provides load-acquire wrt
 	 * interrupts, there are paired barrier()/WRITE_ONCE() in
-	 * kcov_ioctl_locked().
+	 * kcov_start().
 	 */
 	barrier();
 	return mode == needed_mode;
@@ -227,6 +312,78 @@ void notrace __sanitizer_cov_trace_switc
 EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
 #endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */
 
+static void kcov_start(struct task_struct *t, unsigned int size,
+			void *area, enum kcov_mode mode, int sequence)
+{
+	kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
+	/* Cache in task struct for performance. */
+	t->kcov_size = size;
+	t->kcov_area = area;
+	/* See comment in check_kcov_mode(). */
+	barrier();
+	WRITE_ONCE(t->kcov_mode, mode);
+	t->kcov_sequence = sequence;
+}
+
+static void kcov_stop(struct task_struct *t)
+{
+	WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
+	barrier();
+	t->kcov_size = 0;
+	t->kcov_area = NULL;
+}
+
+static void kcov_task_reset(struct task_struct *t)
+{
+	kcov_stop(t);
+	t->kcov = NULL;
+	t->kcov_sequence = 0;
+	t->kcov_handle = 0;
+}
+
+void kcov_task_init(struct task_struct *t)
+{
+	kcov_task_reset(t);
+	t->kcov_handle = current->kcov_handle;
+}
+
+static void kcov_reset(struct kcov *kcov)
+{
+	kcov->t = NULL;
+	kcov->mode = KCOV_MODE_INIT;
+	kcov->remote = false;
+	kcov->remote_size = 0;
+	kcov->sequence++;
+}
+
+static void kcov_remote_reset(struct kcov *kcov)
+{
+	int bkt;
+	struct kcov_remote *remote;
+	struct hlist_node *tmp;
+
+	spin_lock(&kcov_remote_lock);
+	hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) {
+		if (remote->kcov != kcov)
+			continue;
+		kcov_debug("removing handle %llx\n", remote->handle);
+		hash_del(&remote->hnode);
+		kfree(remote);
+	}
+	/* Do reset before unlock to prevent races with kcov_remote_start(). */
+	kcov_reset(kcov);
+	spin_unlock(&kcov_remote_lock);
+}
+
+static void kcov_disable(struct task_struct *t, struct kcov *kcov)
+{
+	kcov_task_reset(t);
+	if (kcov->remote)
+		kcov_remote_reset(kcov);
+	else
+		kcov_reset(kcov);
+}
+
 static void kcov_get(struct kcov *kcov)
 {
 	refcount_inc(&kcov->refcount);
@@ -235,20 +392,12 @@ static void kcov_get(struct kcov *kcov)
 static void kcov_put(struct kcov *kcov)
 {
 	if (refcount_dec_and_test(&kcov->refcount)) {
+		kcov_remote_reset(kcov);
 		vfree(kcov->area);
 		kfree(kcov);
 	}
 }
 
-void kcov_task_init(struct task_struct *t)
-{
-	WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
-	barrier();
-	t->kcov_size = 0;
-	t->kcov_area = NULL;
-	t->kcov = NULL;
-}
-
 void kcov_task_exit(struct task_struct *t)
 {
 	struct kcov *kcov;
@@ -256,15 +405,36 @@ void kcov_task_exit(struct task_struct *
 	kcov = t->kcov;
 	if (kcov == NULL)
 		return;
+
 	spin_lock(&kcov->lock);
+	kcov_debug("t = %px, kcov->t = %px\n", t, kcov->t);
+	/*
+	 * For KCOV_ENABLE devices we want to make sure that t->kcov->t == t,
+	 * which comes down to:
+	 *        WARN_ON(!kcov->remote && kcov->t != t);
+	 *
+	 * For KCOV_REMOTE_ENABLE devices, the exiting task is either:
+	 * 2. A remote task between kcov_remote_start() and kcov_remote_stop().
+	 *    In this case we should print a warning right away, since a task
+	 *    shouldn't be exiting when it's in a kcov coverage collection
+	 *    section. Here t points to the task that is collecting remote
+	 *    coverage, and t->kcov->t points to the thread that created the
+	 *    kcov device. Which means that to detect this case we need to
+	 *    check that t != t->kcov->t, and this gives us the following:
+	 *        WARN_ON(kcov->remote && kcov->t != t);
+	 *
+	 * 2. The task that created kcov exiting without calling KCOV_DISABLE,
+	 *    and then again we can make sure that t->kcov->t == t:
+	 *        WARN_ON(kcov->remote && kcov->t != t);
+	 *
+	 * By combining all three checks into one we get:
+	 */
 	if (WARN_ON(kcov->t != t)) {
 		spin_unlock(&kcov->lock);
 		return;
 	}
 	/* Just to not leave dangling references behind. */
-	kcov_task_init(t);
-	kcov->t = NULL;
-	kcov->mode = KCOV_MODE_INIT;
+	kcov_disable(t, kcov);
 	spin_unlock(&kcov->lock);
 	kcov_put(kcov);
 }
@@ -313,6 +483,7 @@ static int kcov_open(struct inode *inode
 	if (!kcov)
 		return -ENOMEM;
 	kcov->mode = KCOV_MODE_DISABLED;
+	kcov->sequence = 1;
 	refcount_set(&kcov->refcount, 1);
 	spin_lock_init(&kcov->lock);
 	filep->private_data = kcov;
@@ -325,6 +496,20 @@ static int kcov_close(struct inode *inod
 	return 0;
 }
 
+static int kcov_get_mode(unsigned long arg)
+{
+	if (arg == KCOV_TRACE_PC)
+		return KCOV_MODE_TRACE_PC;
+	else if (arg == KCOV_TRACE_CMP)
+#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
+		return KCOV_MODE_TRACE_CMP;
+#else
+		return -ENOTSUPP;
+#endif
+	else
+		return -EINVAL;
+}
+
 /*
  * Fault in a lazily-faulted vmalloc area before it can be used by
  * __santizer_cov_trace_pc(), to avoid recursion issues if any code on the
@@ -340,14 +525,35 @@ static void kcov_fault_in_area(struct kc
 		READ_ONCE(area[offset]);
 }
 
+static inline bool kcov_check_handle(u64 handle, bool common_valid,
+				bool uncommon_valid, bool zero_valid)
+{
+	if (handle & ~(KCOV_SUBSYSTEM_MASK | KCOV_INSTANCE_MASK))
+		return false;
+	switch (handle & KCOV_SUBSYSTEM_MASK) {
+	case KCOV_SUBSYSTEM_COMMON:
+		return (handle & KCOV_INSTANCE_MASK) ?
+			common_valid : zero_valid;
+	case KCOV_SUBSYSTEM_USB:
+		return uncommon_valid;
+	default:
+		return false;
+	}
+	return false;
+}
+
 static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct task_struct *t;
 	unsigned long size, unused;
+	int mode, i;
+	struct kcov_remote_arg *remote_arg;
+	struct kcov_remote *remote;
 
 	switch (cmd) {
 	case KCOV_INIT_TRACE:
+		kcov_debug("KCOV_INIT_TRACE\n");
 		/*
 		 * Enable kcov in trace mode and setup buffer size.
 		 * Must happen before anything else.
@@ -366,6 +572,7 @@ static int kcov_ioctl_locked(struct kcov
 		kcov->mode = KCOV_MODE_INIT;
 		return 0;
 	case KCOV_ENABLE:
+		kcov_debug("KCOV_ENABLE\n");
 		/*
 		 * Enable coverage for the current task.
 		 * At this point user must have been enabled trace mode,
@@ -378,29 +585,20 @@ static int kcov_ioctl_locked(struct kcov
 		t = current;
 		if (kcov->t != NULL || t->kcov != NULL)
 			return -EBUSY;
-		if (arg == KCOV_TRACE_PC)
-			kcov->mode = KCOV_MODE_TRACE_PC;
-		else if (arg == KCOV_TRACE_CMP)
-#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
-			kcov->mode = KCOV_MODE_TRACE_CMP;
-#else
-		return -ENOTSUPP;
-#endif
-		else
-			return -EINVAL;
+		mode = kcov_get_mode(arg);
+		if (mode < 0)
+			return mode;
 		kcov_fault_in_area(kcov);
-		/* Cache in task struct for performance. */
-		t->kcov_size = kcov->size;
-		t->kcov_area = kcov->area;
-		/* See comment in check_kcov_mode(). */
-		barrier();
-		WRITE_ONCE(t->kcov_mode, kcov->mode);
+		kcov->mode = mode;
+		kcov_start(t, kcov->size, kcov->area, kcov->mode,
+				kcov->sequence);
 		t->kcov = kcov;
 		kcov->t = t;
-		/* This is put either in kcov_task_exit() or in KCOV_DISABLE. */
+		/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
 		kcov_get(kcov);
 		return 0;
 	case KCOV_DISABLE:
+		kcov_debug("KCOV_DISABLE\n");
 		/* Disable coverage for the current task. */
 		unused = arg;
 		if (unused != 0 || current->kcov != kcov)
@@ -408,11 +606,65 @@ static int kcov_ioctl_locked(struct kcov
 		t = current;
 		if (WARN_ON(kcov->t != t))
 			return -EINVAL;
-		kcov_task_init(t);
-		kcov->t = NULL;
-		kcov->mode = KCOV_MODE_INIT;
+		kcov_disable(t, kcov);
 		kcov_put(kcov);
 		return 0;
+	case KCOV_REMOTE_ENABLE:
+		kcov_debug("KCOV_REMOTE_ENABLE\n");
+		if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
+			return -EINVAL;
+		t = current;
+		if (kcov->t != NULL || t->kcov != NULL)
+			return -EBUSY;
+		remote_arg = (struct kcov_remote_arg *)arg;
+		mode = kcov_get_mode(remote_arg->trace_mode);
+		if (mode < 0)
+			return mode;
+		if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long))
+			return -EINVAL;
+		kcov->mode = mode;
+		t->kcov = kcov;
+		kcov->t = t;
+		kcov->remote = true;
+		kcov->remote_size = remote_arg->area_size;
+		spin_lock(&kcov_remote_lock);
+		for (i = 0; i < remote_arg->num_handles; i++) {
+			kcov_debug("handle %llx\n", remote_arg->handles[i]);
+			if (!kcov_check_handle(remote_arg->handles[i],
+						false, true, false)) {
+				spin_unlock(&kcov_remote_lock);
+				kcov_disable(t, kcov);
+				return -EINVAL;
+			}
+			remote = kcov_remote_add(kcov, remote_arg->handles[i]);
+			if (IS_ERR(remote)) {
+				spin_unlock(&kcov_remote_lock);
+				kcov_disable(t, kcov);
+				return PTR_ERR(remote);
+			}
+		}
+		if (remote_arg->common_handle) {
+			kcov_debug("common handle %llx\n",
+					remote_arg->common_handle);
+			if (!kcov_check_handle(remote_arg->common_handle,
+						true, false, false)) {
+				spin_unlock(&kcov_remote_lock);
+				kcov_disable(t, kcov);
+				return -EINVAL;
+			}
+			remote = kcov_remote_add(kcov,
+					remote_arg->common_handle);
+			if (IS_ERR(remote)) {
+				spin_unlock(&kcov_remote_lock);
+				kcov_disable(t, kcov);
+				return PTR_ERR(remote);
+			}
+			t->kcov_handle = remote_arg->common_handle;
+		}
+		spin_unlock(&kcov_remote_lock);
+		/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
+		kcov_get(kcov);
+		return 0;
 	default:
 		return -ENOTTY;
 	}
@@ -422,11 +674,35 @@ static long kcov_ioctl(struct file *file
 {
 	struct kcov *kcov;
 	int res;
+	struct kcov_remote_arg *remote_arg = NULL;
+	unsigned int remote_num_handles;
+	unsigned long remote_arg_size;
+
+	if (cmd == KCOV_REMOTE_ENABLE) {
+		if (get_user(remote_num_handles, (unsigned __user *)(arg +
+				offsetof(struct kcov_remote_arg, num_handles))))
+			return -EFAULT;
+		if (remote_num_handles > KCOV_REMOTE_MAX_HANDLES)
+			return -EINVAL;
+		remote_arg_size = struct_size(remote_arg, handles,
+					remote_num_handles);
+		remote_arg = memdup_user((void __user *)arg, remote_arg_size);
+		if (IS_ERR(remote_arg))
+			return PTR_ERR(remote_arg);
+		if (remote_arg->num_handles != remote_num_handles) {
+			kfree(remote_arg);
+			return -EINVAL;
+		}
+		arg = (unsigned long)remote_arg;
+	}
 
 	kcov = filep->private_data;
 	spin_lock(&kcov->lock);
 	res = kcov_ioctl_locked(kcov, cmd, arg);
 	spin_unlock(&kcov->lock);
+
+	kfree(remote_arg);
+
 	return res;
 }
 
@@ -438,6 +714,207 @@ static const struct file_operations kcov
 	.release        = kcov_close,
 };
 
+/*
+ * kcov_remote_start() and kcov_remote_stop() can be used to annotate a section
+ * of code in a kernel background thread to allow kcov to be used to collect
+ * coverage from that part of code.
+ *
+ * The handle argument of kcov_remote_start() identifies a code section that is
+ * used for coverage collection. A userspace process passes this handle to
+ * KCOV_REMOTE_ENABLE ioctl to make the used kcov device start collecting
+ * coverage for the code section identified by this handle.
+ *
+ * The usage of these annotations in the kernel code is different depending on
+ * the type of the kernel thread whose code is being annotated.
+ *
+ * For global kernel threads that are spawned in a limited number of instances
+ * (e.g. one USB hub_event() worker thread is spawned per USB HCD), each
+ * instance must be assigned a unique 4-byte instance id. The instance id is
+ * then combined with a 1-byte subsystem id to get a handle via
+ * kcov_remote_handle(subsystem_id, instance_id).
+ *
+ * For local kernel threads that are spawned from system calls handler when a
+ * user interacts with some kernel interface (e.g. vhost workers), a handle is
+ * passed from a userspace process as the common_handle field of the
+ * kcov_remote_arg struct (note, that the user must generate a handle by using
+ * kcov_remote_handle() with KCOV_SUBSYSTEM_COMMON as the subsystem id and an
+ * arbitrary 4-byte non-zero number as the instance id). This common handle
+ * then gets saved into the task_struct of the process that issued the
+ * KCOV_REMOTE_ENABLE ioctl. When this proccess issues system calls that spawn
+ * kernel threads, the common handle must be retrived via kcov_common_handle()
+ * and passed to the spawned threads via custom annotations. Those kernel
+ * threads must in turn be annotated with kcov_remote_start(common_handle) and
+ * kcov_remote_stop(). All of the threads that are spawned by the same process
+ * obtain the same handle, hence the name "common".
+ *
+ * See Documentation/dev-tools/kcov.rst for more details.
+ *
+ * Internally, this function looks up the kcov device associated with the
+ * provided handle, allocates an area for coverage collection, and saves the
+ * pointers to kcov and area into the current task_struct to allow coverage to
+ * be collected via __sanitizer_cov_trace_pc()
+ * In turns kcov_remote_stop() clears those pointers from task_struct to stop
+ * collecting coverage and copies all collected coverage into the kcov area.
+ */
+void kcov_remote_start(u64 handle)
+{
+	struct kcov_remote *remote;
+	void *area;
+	struct task_struct *t;
+	unsigned int size;
+	enum kcov_mode mode;
+	int sequence;
+
+	if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
+		return;
+	if (WARN_ON(!in_task()))
+		return;
+	t = current;
+	/*
+	 * Check that kcov_remote_start is not called twice
+	 * nor called by user tasks (with enabled kcov).
+	 */
+	if (WARN_ON(t->kcov))
+		return;
+
+	kcov_debug("handle = %llx\n", handle);
+
+	spin_lock(&kcov_remote_lock);
+	remote = kcov_remote_find(handle);
+	if (!remote) {
+		kcov_debug("no remote found");
+		spin_unlock(&kcov_remote_lock);
+		return;
+	}
+	/* Put in kcov_remote_stop(). */
+	kcov_get(remote->kcov);
+	t->kcov = remote->kcov;
+	/*
+	 * Read kcov fields before unlock to prevent races with
+	 * KCOV_DISABLE / kcov_remote_reset().
+	 */
+	size = remote->kcov->remote_size;
+	mode = remote->kcov->mode;
+	sequence = remote->kcov->sequence;
+	area = kcov_remote_area_get(size);
+	spin_unlock(&kcov_remote_lock);
+
+	if (!area) {
+		area = vmalloc(size * sizeof(unsigned long));
+		if (!area) {
+			t->kcov = NULL;
+			kcov_put(remote->kcov);
+			return;
+		}
+	}
+	/* Reset coverage size. */
+	*(u64 *)area = 0;
+
+	kcov_debug("area = %px, size = %u", area, size);
+
+	kcov_start(t, size, area, mode, sequence);
+
+}
+EXPORT_SYMBOL(kcov_remote_start);
+
+static void kcov_move_area(enum kcov_mode mode, void *dst_area,
+				unsigned int dst_area_size, void *src_area)
+{
+	u64 word_size = sizeof(unsigned long);
+	u64 count_size, entry_size_log;
+	u64 dst_len, src_len;
+	void *dst_entries, *src_entries;
+	u64 dst_occupied, dst_free, bytes_to_move, entries_moved;
+
+	kcov_debug("%px %u <= %px %lu\n",
+		dst_area, dst_area_size, src_area, *(unsigned long *)src_area);
+
+	switch (mode) {
+	case KCOV_MODE_TRACE_PC:
+		dst_len = READ_ONCE(*(unsigned long *)dst_area);
+		src_len = *(unsigned long *)src_area;
+		count_size = sizeof(unsigned long);
+		entry_size_log = __ilog2_u64(sizeof(unsigned long));
+		break;
+	case KCOV_MODE_TRACE_CMP:
+		dst_len = READ_ONCE(*(u64 *)dst_area);
+		src_len = *(u64 *)src_area;
+		count_size = sizeof(u64);
+		BUILD_BUG_ON(!is_power_of_2(KCOV_WORDS_PER_CMP));
+		entry_size_log = __ilog2_u64(sizeof(u64) * KCOV_WORDS_PER_CMP);
+		break;
+	default:
+		WARN_ON(1);
+		return;
+	}
+
+	/* As arm can't divide u64 integers use log of entry size. */
+	if (dst_len > ((dst_area_size * word_size - count_size) >>
+				entry_size_log))
+		return;
+	dst_occupied = count_size + (dst_len << entry_size_log);
+	dst_free = dst_area_size * word_size - dst_occupied;
+	bytes_to_move = min(dst_free, src_len << entry_size_log);
+	dst_entries = dst_area + dst_occupied;
+	src_entries = src_area + count_size;
+	memcpy(dst_entries, src_entries, bytes_to_move);
+	entries_moved = bytes_to_move >> entry_size_log;
+
+	switch (mode) {
+	case KCOV_MODE_TRACE_PC:
+		WRITE_ONCE(*(unsigned long *)dst_area, dst_len + entries_moved);
+		break;
+	case KCOV_MODE_TRACE_CMP:
+		WRITE_ONCE(*(u64 *)dst_area, dst_len + entries_moved);
+		break;
+	default:
+		break;
+	}
+}
+
+/* See the comment before kcov_remote_start() for usage details. */
+void kcov_remote_stop(void)
+{
+	struct task_struct *t = current;
+	struct kcov *kcov = t->kcov;
+	void *area = t->kcov_area;
+	unsigned int size = t->kcov_size;
+	int sequence = t->kcov_sequence;
+
+	if (!kcov) {
+		kcov_debug("no kcov found\n");
+		return;
+	}
+
+	kcov_stop(t);
+	t->kcov = NULL;
+
+	spin_lock(&kcov->lock);
+	/*
+	 * KCOV_DISABLE could have been called between kcov_remote_start()
+	 * and kcov_remote_stop(), hence the check.
+	 */
+	kcov_debug("move if: %d == %d && %d\n",
+		sequence, kcov->sequence, (int)kcov->remote);
+	if (sequence == kcov->sequence && kcov->remote)
+		kcov_move_area(kcov->mode, kcov->area, kcov->size, area);
+	spin_unlock(&kcov->lock);
+
+	spin_lock(&kcov_remote_lock);
+	kcov_remote_area_put(area, size);
+	spin_unlock(&kcov_remote_lock);
+
+	kcov_put(kcov);
+}
+EXPORT_SYMBOL(kcov_remote_stop);
+
+/* See the comment before kcov_remote_start() for usage details. */
+u64 kcov_common_handle(void)
+{
+	return current->kcov_handle;
+}
+EXPORT_SYMBOL(kcov_common_handle);
+
 static int __init kcov_init(void)
 {
 	/*
_


  parent reply index

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-05  0:48 incoming Andrew Morton
2019-12-05  0:49 ` [patch 01/86] mm/kasan/common.c: fix compile error Andrew Morton
2019-12-05  0:49 ` [patch 02/86] mm: memcg/slab: wait for !root kmem_cache refcnt killing on root kmem_cache destruction Andrew Morton
2019-12-05  0:49 ` [patch 03/86] mm/vmstat: add helpers to get vmstat item names for each enum type Andrew Morton
2019-12-05  0:49 ` [patch 04/86] mm/memcontrol: use vmstat names for printing statistics Andrew Morton
2019-12-05  0:49 ` [patch 05/86] mm/memory.c: replace is_zero_pfn with is_huge_zero_pmd for thp Andrew Morton
2019-12-05  0:49 ` [patch 06/86] proc: change ->nlink under proc_subdir_lock Andrew Morton
2019-12-05  0:50 ` [patch 07/86] fs/proc/generic.c: delete useless "len" variable Andrew Morton
2019-12-05  0:50 ` [patch 08/86] fs/proc/internal.h: shuffle "struct pde_opener" Andrew Morton
2019-12-05  0:50 ` [patch 09/86] include/linux/proc_fs.h: fix confusing macro arg name Andrew Morton
2019-12-05  0:50 ` [patch 10/86] fs/proc/Kconfig: fix indentation Andrew Morton
2019-12-05  0:50 ` [patch 11/86] include/linux/sysctl.h: inline braces for ctl_table and ctl_table_header Andrew Morton
2019-12-05  0:50 ` [patch 12/86] .gitattributes: use 'dts' diff driver for dts files Andrew Morton
2019-12-05  1:00   ` Frank Rowand
2019-12-05  0:50 ` [patch 13/86] linux/build_bug.h: change type to int Andrew Morton
2019-12-05  0:50 ` [patch 14/86] linux/scc.h: make uapi linux/scc.h self-contained Andrew Morton
2019-12-05  0:50 ` [patch 15/86] arch/Kconfig: fix indentation Andrew Morton
2019-12-05  0:50 ` [patch 16/86] scripts/get_maintainer.pl: add signatures from Fixes: <badcommit> lines in commit message Andrew Morton
2019-12-05  0:50 ` [patch 17/86] kernel.h: update comment about simple_strto<foo>() functions Andrew Morton
2019-12-05  0:50 ` [patch 18/86] auxdisplay: charlcd: deduplicate simple_strtoul() Andrew Morton
2019-12-05  0:50 ` [patch 19/86] kernel/notifier.c: intercept duplicate registrations to avoid infinite loops Andrew Morton
2019-12-05  0:50 ` [patch 20/86] kernel/notifier.c: remove notifier_chain_cond_register() Andrew Morton
2019-12-05  0:50 ` [patch 21/86] kernel/notifier.c: remove blocking_notifier_chain_cond_register() Andrew Morton
2019-12-05  0:50 ` [patch 22/86] kernel/profile.c: use cpumask_available to check for NULL cpumask Andrew Morton
2019-12-05  0:50 ` [patch 23/86] kernel/sys.c: avoid copying possible padding bytes in copy_to_user Andrew Morton
2019-12-05  0:50 ` [patch 24/86] bitops: introduce the for_each_set_clump8 macro Andrew Morton
2019-12-05  0:51 ` [patch 25/86] lib/test_bitmap.c: add for_each_set_clump8 test cases Andrew Morton
2019-12-05  0:51 ` [patch 26/86] gpio: 104-dio-48e: utilize for_each_set_clump8 macro Andrew Morton
2019-12-05  0:51 ` [patch 27/86] gpio: 104-idi-48: " Andrew Morton
2019-12-05  0:51 ` [patch 28/86] gpio: gpio-mm: " Andrew Morton
2019-12-05  0:51 ` [patch 29/86] gpio: ws16c48: " Andrew Morton
2019-12-05  0:51 ` [patch 30/86] gpio: pci-idio-16: " Andrew Morton
2019-12-05  0:51 ` [patch 31/86] gpio: pcie-idio-24: " Andrew Morton
2019-12-05  0:51 ` [patch 32/86] gpio: uniphier: " Andrew Morton
2019-12-05  0:51 ` [patch 33/86] gpio: 74x164: utilize the " Andrew Morton
2019-12-05  0:51 ` [patch 34/86] thermal: intel: intel_soc_dts_iosf: Utilize " Andrew Morton
2019-12-05  0:51 ` [patch 35/86] gpio: pisosr: utilize the " Andrew Morton
2019-12-05  0:51 ` [patch 36/86] gpio: max3191x: " Andrew Morton
2019-12-05  0:51 ` [patch 37/86] gpio: pca953x: " Andrew Morton
2019-12-05  0:51 ` [patch 38/86] lib/rbtree: set successor's parent unconditionally Andrew Morton
2019-12-05  0:51 ` [patch 39/86] lib/rbtree: get successor's color directly Andrew Morton
2019-12-05  0:51 ` [patch 40/86] lib/test_meminit.c: add bulk alloc/free tests Andrew Morton
2019-12-05  0:51 ` [patch 41/86] lib/math/rational.c: fix possible incorrect result from rational fractions helper Andrew Morton
2019-12-05  0:52 ` [patch 42/86] lib/genalloc.c: export symbol addr_in_gen_pool Andrew Morton
2019-12-05  0:52 ` [patch 43/86] lib/genalloc.c: rename addr_in_gen_pool to gen_pool_has_addr Andrew Morton
2019-12-05  0:52 ` [patch 44/86] checkpatch: improve ignoring CamelCase SI style variants like mA Andrew Morton
2019-12-05  0:52 ` [patch 45/86] checkpatch: reduce is_maintained_obsolete lookup runtime Andrew Morton
2019-12-05  0:52 ` [patch 46/86] epoll: simplify ep_poll_safewake() for CONFIG_DEBUG_LOCK_ALLOC Andrew Morton
2019-12-05  0:52 ` [patch 47/86] fs/epoll: remove unnecessary wakeups of nested epoll Andrew Morton
2019-12-05  0:52 ` [patch 48/86] selftests: add epoll selftests Andrew Morton
2019-12-05  0:52 ` [patch 49/86] fs/binfmt_elf.c: delete unused "interp_map_addr" argument Andrew Morton
2019-12-05  0:52 ` [patch 50/86] fs/binfmt_elf.c: extract elf_read() function Andrew Morton
2019-12-05  0:52 ` [patch 51/86] init/Kconfig: fix indentation Andrew Morton
2019-12-05  0:52 ` [patch 52/86] drivers/rapidio/rio-driver.c: fix missing include of <linux/rio_drv.h> Andrew Morton
2019-12-05  0:52 ` [patch 53/86] drivers/rapidio/rio-access.c: " Andrew Morton
2019-12-05  0:52 ` [patch 54/86] drm: limit to INT_MAX in create_blob ioctl Andrew Morton
2019-12-05  0:52 ` [patch 55/86] uaccess: disallow > INT_MAX copy sizes Andrew Morton
2019-12-05  0:52 ` Andrew Morton [this message]
2019-12-05  0:52 ` [patch 57/86] usb, kcov: collect coverage from hub_event Andrew Morton
2019-12-05  0:52 ` [patch 58/86] vhost, kcov: collect coverage from vhost_worker Andrew Morton
2019-12-05  0:52 ` [patch 59/86] lib/ubsan: don't serialize UBSAN report Andrew Morton
2019-12-05  0:52 ` [patch 60/86] arch: ipcbuf.h: make uapi asm/ipcbuf.h self-contained Andrew Morton
2019-12-05  0:53 ` [patch 61/86] arch: msgbuf.h: make uapi asm/msgbuf.h self-contained Andrew Morton
2019-12-05  0:53 ` [patch 62/86] arch: sembuf.h: make uapi asm/sembuf.h self-contained Andrew Morton
2019-12-05  0:53 ` [patch 63/86] lib/test_bitmap: force argument of bitmap_parselist_user() to proper address space Andrew Morton
2019-12-05  0:53 ` [patch 64/86] lib/test_bitmap: undefine macros after use Andrew Morton
2019-12-05  0:53 ` [patch 65/86] lib/test_bitmap: name EXP_BYTES properly Andrew Morton
2019-12-05  0:53 ` [patch 66/86] lib/test_bitmap: rename exp to exp1 to avoid ambiguous name Andrew Morton
2019-12-05  0:53 ` [patch 67/86] lib/test_bitmap: move exp1 and exp2 upper for others to use Andrew Morton
2019-12-05  0:53 ` [patch 68/86] lib/test_bitmap: fix comment about this file Andrew Morton
2019-12-05  0:53 ` [patch 69/86] lib/bitmap: introduce bitmap_replace() helper Andrew Morton
2019-12-05  0:53 ` [patch 70/86] gpio: pca953x: remove redundant variable and check in IRQ handler Andrew Morton
2019-12-05  0:53 ` [patch 71/86] gpio: pca953x: use input from regs structure in pca953x_irq_pending() Andrew Morton
2019-12-05  0:53 ` [patch 72/86] gpio: pca953x: convert to use bitmap API Andrew Morton
2019-12-05  0:53 ` [patch 73/86] gpio: pca953x: tighten up indentation Andrew Morton
2019-12-05  0:53 ` [patch 74/86] alpha: use pgtable-nopud instead of 4level-fixup Andrew Morton
2019-12-05  0:53 ` [patch 75/86] arm: nommu: " Andrew Morton
2019-12-05  0:53 ` [patch 76/86] c6x: " Andrew Morton
2019-12-05  0:53 ` [patch 77/86] m68k: nommu: " Andrew Morton
2019-12-05  0:53 ` [patch 78/86] m68k: mm: use pgtable-nopXd " Andrew Morton
2019-12-05  0:54 ` [patch 79/86] microblaze: use pgtable-nopmd " Andrew Morton
2019-12-05  0:54 ` [patch 80/86] nds32: " Andrew Morton
2019-12-05  0:54 ` [patch 81/86] parisc: use pgtable-nopXd " Andrew Morton
2019-12-05  0:54 ` [patch 82/86] parisc/hugetlb: " Andrew Morton
2019-12-05  0:54 ` [patch 83/86] sparc32: use pgtable-nopud " Andrew Morton
2019-12-05  0:54 ` [patch 84/86] um: remove unused pxx_offset_proc() and addr_pte() functions Andrew Morton
2019-12-05  0:54 ` [patch 85/86] um: add support for folded p4d page tables Andrew Morton
2019-12-05  0:54 ` [patch 86/86] mm: remove __ARCH_HAS_4LEVEL_HACK and include/asm-generic/4level-fixup.h Andrew Morton

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