4 files changed, 28 insertions, 18 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 5773f0ba7e76..5ef0484513ec 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -3,6 +3,9 @@
  * Copyright (C) 2006 Jens Axboe <[email protected]>
  *
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
 #include <linux/blktrace_api.h>
@@ -344,7 +347,8 @@ static int __blk_trace_remove(struct request_queue *q)
 {
 	struct blk_trace *bt;
 
-	bt = xchg(&q->blk_trace, NULL);
+	bt = rcu_replace_pointer(q->blk_trace, NULL,
+				 lockdep_is_held(&q->blk_trace_mutex));
 	if (!bt)
 		return -EINVAL;
 
@@ -494,6 +498,17 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	 */
 	strreplace(buts->name, '/', '_');
 
+	/*
+	 * bdev can be NULL, as with scsi-generic, this is a helpful as
+	 * we can be.
+	 */
+	if (rcu_dereference_protected(q->blk_trace,
+				      lockdep_is_held(&q->blk_trace_mutex))) {
+		pr_warn("Concurrent blktraces are not allowed on %s\n",
+			buts->name);
+		return -EBUSY;
+	}
+
 	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
 	if (!bt)
 		return -ENOMEM;
@@ -543,10 +558,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	bt->pid = buts->pid;
 	bt->trace_state = Blktrace_setup;
 
-	ret = -EBUSY;
-	if (cmpxchg(&q->blk_trace, NULL, bt))
-		goto err;
-
+	rcu_assign_pointer(q->blk_trace, bt);
 	get_probe_ref();
 
 	ret = 0;
@@ -1629,7 +1641,8 @@ static int blk_trace_remove_queue(struct request_queue *q)
 {
 	struct blk_trace *bt;
 
-	bt = xchg(&q->blk_trace, NULL);
+	bt = rcu_replace_pointer(q->blk_trace, NULL,
+				 lockdep_is_held(&q->blk_trace_mutex));
 	if (bt == NULL)
 		return -EINVAL;
 
@@ -1661,10 +1674,7 @@ static int blk_trace_setup_queue(struct request_queue *q,
 
 	blk_trace_setup_lba(bt, bdev);
 
-	ret = -EBUSY;
-	if (cmpxchg(&q->blk_trace, NULL, bt))
-		goto free_bt;
-
+	rcu_assign_pointer(q->blk_trace, bt);
 	get_probe_ref();
 	return 0;
 
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index e729c9e587a0..dc05626979b8 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -141,7 +141,7 @@ bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr)
 {
 	int ret;
 
-	ret = probe_user_read(dst, unsafe_ptr, size);
+	ret = copy_from_user_nofault(dst, unsafe_ptr, size);
 	if (unlikely(ret < 0))
 		memset(dst, 0, size);
 	return ret;
@@ -196,7 +196,7 @@ bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr)
 
 	if (unlikely(ret < 0))
 		goto fail;
-	ret = probe_kernel_read(dst, unsafe_ptr, size);
+	ret = copy_from_kernel_nofault(dst, unsafe_ptr, size);
 	if (unlikely(ret < 0))
 		goto fail;
 	return ret;
@@ -326,7 +326,7 @@ BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src,
 	if (unlikely(!nmi_uaccess_okay()))
 		return -EPERM;
 
-	return probe_user_write(unsafe_ptr, src, size);
+	return copy_to_user_nofault(unsafe_ptr, src, size);
 }
 
 static const struct bpf_func_proto bpf_probe_write_user_proto = {
@@ -661,7 +661,7 @@ BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
 
 			copy_size = (fmt[i + 2] == '4') ? 4 : 16;
 
-			err = probe_kernel_read(bufs->buf[memcpy_cnt],
+			err = copy_from_kernel_nofault(bufs->buf[memcpy_cnt],
 						(void *) (long) args[fmt_cnt],
 						copy_size);
 			if (err < 0)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6048f1be26d2..aefb6065b508 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1222,7 +1222,7 @@ fetch_store_strlen(unsigned long addr)
 #endif
 
 	do {
-		ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
+		ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
 		len++;
 	} while (c && ret == 0 && len < MAX_STRING_SIZE);
 
@@ -1290,7 +1290,7 @@ probe_mem_read_user(void *dest, void *src, size_t size)
 {
 	const void __user *uaddr =  (__force const void __user *)src;
 
-	return probe_user_read(dest, uaddr, size);
+	return copy_from_user_nofault(dest, uaddr, size);
 }
 
 static nokprobe_inline int
@@ -1300,7 +1300,7 @@ probe_mem_read(void *dest, void *src, size_t size)
 	if ((unsigned long)src < TASK_SIZE)
 		return probe_mem_read_user(dest, src, size);
 #endif
-	return probe_kernel_read(dest, src, size);
+	return copy_from_kernel_nofault(dest, src, size);
 }
 
 /* Note that we don't verify it, since the code does not come from user space */
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index a0ff9e200ef6..a22b62813f8c 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -236,7 +236,7 @@ struct trace_probe_event {
 	struct trace_event_call		call;
 	struct list_head 		files;
 	struct list_head		probes;
-	struct trace_uprobe_filter	filter[0];
+	struct trace_uprobe_filter	filter[];
 };
 
 struct trace_probe {