cgroup: Initialize root in cgroup_mount

PATCH In review Jason Low 2 participants 4 messages Jan 27, 2015

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Jason Low

author

2015-01-27 00:22 UTC #0 lore raw

PATCH 1/1 cgroup: Initialize root in cgroup_mount

Compiling kernel/ causes warnings:

... ‘root’ may be used uninitialized in this function ... ‘root’ was declared here

This isn't an issue since there is already logic to not use root if we goto out_unlock without setting root.

Explicitly initialize root to NULL to suppress this so that we can focus on catching warnings that can potentially cause bigger issues.

Signed-off-by Jason Low <[email protected]>

---
 kernel/cgroup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

kernel/cgroup.c +1 -1

index bb263d0..66684f3 100644
@@ -1738,8 +1738,8 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 			 void *data)
 {
 	struct super_block *pinned_sb = NULL;
+	struct cgroup_root *root = NULL;
 	struct cgroup_subsys *ss;
-	struct cgroup_root *root;
 	struct cgroup_sb_opts opts;
 	struct dentry *dentry;
 	int ret;

Signature · 1 line

1.7.1

Tejun Heo

2015-01-27 16:10 UTC #1 lore raw

Quoted 10 lines · Jason Low

Compiling kernel/ causes warnings:
... ‘root’ may be used uninitialized in this function ... ‘root’ was declared here
This isn't an issue since there is already logic to not use root if we goto out_unlock without setting root.
Explicitly initialize root to NULL to suppress this so that we can focus on catching warnings that can potentially cause bigger issues.

Which complier are you using? The variable, AFAICS, is always set before being deref'd and the function hasn't triggered spurious warnings for quite a while with differing versions of gcc.

Thanks.

Signature · 1 line

tejun

Jason Low

author

2015-01-27 17:51 UTC #2 lore raw

Quoted 6 lines · Tejun Heo

Quoted 5 lines · Jason Low
Compiling kernel/ causes warnings:
... ‘root’ may be used uninitialized in this function ... ‘root’ was declared here

Quoted 7 lines

Quoted 5 lines
This isn't an issue since there is already logic to not use root if we goto out_unlock without setting root.
Explicitly initialize root to NULL to suppress this so that we can focus on catching warnings that can potentially cause bigger issues.
Which complier are you using?

Hi Tejun, one of the versions I am seeing this on is gcc 4.6.3.

Quoted 3 lines

The variable, AFAICS, is always set
before being deref'd and the function hasn't triggered spurious warnings for quite a while with differing versions of gcc.

Tejun Heo

2015-01-27 18:18 UTC #3 lore raw

Quoted 10 lines · Jason Low

Quoted 9 lines · Tejun Heo
Quoted 8 lines · Jason Low
Compiling kernel/ causes warnings:
... ‘root’ may be used uninitialized in this function ... ‘root’ was declared here
This isn't an issue since there is already logic to not use root if we goto out_unlock without setting root.

Quoted 6 lines

Quoted 4 lines
Quoted 2 lines
Explicitly initialize root to NULL to suppress this so that we can focus on catching warnings that can potentially cause bigger issues.
Which complier are you using?
Hi Tejun, one of the versions I am seeing this on is gcc 4.6.3.

Can you plesae try something newer? gcc for a while had trouble with these spurious warnings. 4.6.2 is 3+ years old now.

Thanks.

Signature · 1 line

tejun