@@ -617,8 +617,9 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
return ret;
}
-static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
- struct block_device *bdev, char __user *arg)
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ struct block_device *bdev,
+ char __user *arg)
{
struct blk_user_trace_setup buts;
int ret;
@@ -627,26 +628,17 @@ static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
if (ret)
return -EFAULT;
+ mutex_lock(&q->debugfs_mutex);
ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+ mutex_unlock(&q->debugfs_mutex);
if (ret)
return ret;
if (copy_to_user(arg, &buts, sizeof(buts))) {
- __blk_trace_remove(q);
+ blk_trace_remove(q);
return -EFAULT;
}
return 0;
-}
-
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
- struct block_device *bdev,
- char __user *arg)
-{
- int ret;
-
- mutex_lock(&q->debugfs_mutex);
- ret = __blk_trace_setup(q, name, dev, bdev, arg);
- mutex_unlock(&q->debugfs_mutex);
return ret;
}
@@ -673,12 +665,14 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
.pid = cbuts.pid,
};
+ mutex_lock(&q->debugfs_mutex);
ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+ mutex_unlock(&q->debugfs_mutex);
if (ret)
return ret;
if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
- __blk_trace_remove(q);
+ blk_trace_remove(q);
return -EFAULT;
}
@@ -740,9 +734,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
case BLKTRACESETUP32:
snprintf(b, sizeof(b), "%pg", bdev);
- mutex_lock(&q->debugfs_mutex);
ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
- mutex_unlock(&q->debugfs_mutex);
break;
#endif
case BLKTRACESTART:
Move copy_[to|from]_user() out of ->debugfs_lock and cut the dependency between mm->mmap_lock and q->debugfs_lock, then we avoids lots of lockdep false positive warning. Obviously ->debug_lock isn't needed for copy_[to|from]_user(). The only behavior change is to call blk_trace_remove() in case of setup failure handling by re-grabbing ->debugfs_lock, and this way is just fine since we do cover concurrent setup() & remove(). Reported-by: syzbot+91585b36b538053343e4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-block/67450fd4.050a0220.1286eb.0007.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/6742e584.050a0220.1cc393.0038.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/6742a600.050a0220.1cc393.002e.GAE@google.com/ Closes: https://lore.kernel.org/linux-block/67420102.050a0220.1cc393.0019.GAE@google.com/ Signed-off-by: Ming Lei <ming.lei@redhat.com> --- kernel/trace/blktrace.c | 26 +++++++++----------------- 1 file changed, 9 insertions(+), 17 deletions(-)