On Wed, 2012-03-07 at 14:49 +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2012-03-06 at 10:26 +0100, masterzorag wrote:
> > I'm running my test program, it uses all available spus to compute via
> > OpenCL
> > kernel 3.2.5 on a ps3
> > even on testing spu directly, it crashes
>
> I think the patch is not 100% right yet. Looking at the code, we
> have a real mess of who gets to clean what up here. This is an
> attempt at sorting things by having the mutex and dentry dropped
> in spufs_create() always. Can you give it a spin (untested):
>
> Al, I'm not familiar with the vfs, can you take a quick look ?
Better with the actual patch :-)
powerpc/cell: Fix locking in spufs_create()
The error path in spufs_create() could cause double unlocks
among other horrors. Clean it up.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Reported-by: masterzo...@gmail.com
diff --git a/arch/powerpc/platforms/cell/spufs/inode.c
b/arch/powerpc/platforms/cell/spufs/inode.c
index d4a094c..63b4e43 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -454,19 +454,16 @@ spufs_create_context(struct inode *inode, struct dentry
*dentry,
struct spu_gang *gang;
struct spu_context *neighbor;
- ret = -EPERM;
if ((flags & SPU_CREATE_NOSCHED) &&
- !capable(CAP_SYS_NICE))
- goto out_unlock;
+ !capable(CAP_SYa_NICE))
+ return -EPERM;
- ret = -EINVAL;
if ((flags & (SPU_CREATE_NOSCHED | SPU_CREATE_ISOLATE))
== SPU_CREATE_ISOLATE)
- goto out_unlock;
+ return -EINVAL;
- ret = -ENODEV;
if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader)
- goto out_unlock;
+ return -ENODEV;
gang = NULL;
neighbor = NULL;
@@ -512,10 +509,6 @@ spufs_create_context(struct inode *inode, struct dentry
*dentry,
out_aff_unlock:
if (affinity)
mutex_unlock(&gang->aff_mutex);
-out_unlock:
- mutex_unlock(&inode->i_mutex);
-out:
- dput(dentry);
return ret;
}
@@ -585,11 +578,9 @@ static int spufs_create_gang(struct inode *inode,
struct dentry *dentry,
struct vfsmount *mnt, umode_t mode)
{
- int ret;
-
- ret = spufs_mkgang(inode, dentry, mode & S_IRWXUGO);
+ int ret = spufs_mkgang(inode, dentry, mode & S_IRWXUGO);
if (ret)
- goto out;
+ return ret;
/*
* get references for dget and mntget, will be released
@@ -600,10 +591,6 @@ static int spufs_create_gang(struct inode *inode,
int err = simple_rmdir(inode, dentry);
WARN_ON(err);
}
-
-out:
- mutex_unlock(&inode->i_mutex);
- dput(dentry);
return ret;
}
@@ -613,22 +600,21 @@ static struct file_system_type spufs_type;
long spufs_create(struct path *path, struct dentry *dentry,
unsigned int flags, umode_t mode, struct file *filp)
{
- int ret;
+ int ret = -EINVAL;
- ret = -EINVAL;
/* check if we are on spufs */
if (path->dentry->d_sb->s_type != &spufs_type)
- goto out;
+ goto fail;
/* don't accept undefined flags */
if (flags & (~SPU_CREATE_FLAG_ALL))
- goto out;
+ goto fail;
/* only threads can be underneath a gang */
if (path->dentry != path->dentry->d_sb->s_root) {
if ((flags & SPU_CREATE_GANG) ||
!SPUFS_I(path->dentry->d_inode)->i_gang)
- goto out;
+ goto fail;
}
mode &= ~current_umask();
@@ -640,12 +626,17 @@ long spufs_create(struct path *path, struct dentry
*dentry,
ret = spufs_create_context(path->dentry->d_inode,
dentry, path->mnt, flags, mode,
filp);
- if (ret >= 0)
+ if (ret >= 0) {
+ /* We drop these before fsnotify */
+ mutex_unlock(&inode->i_mutex);
+ dput(dentry);
fsnotify_mkdir(path->dentry->d_inode, dentry);
- return ret;
-out:
- mutex_unlock(&path->dentry->d_inode->i_mutex);
+ return ret;
+ }
+ fail:
+ mutex_unlock(&inode->i_mutex);
+ dput(dentry);
return ret;
}
diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c
b/arch/powerpc/platforms/cell/spufs/syscalls.c
index 8591bb6..1a65ef2 100644
--- a/arch/powerpc/platforms/cell/spufs/syscalls.c
+++ b/arch/powerpc/platforms/cell/spufs/syscalls.c
@@ -70,11 +70,8 @@ static long do_spu_create(const char __user *pathname,
unsigned int flags,
ret = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
ret = spufs_create(&path, dentry, flags, mode, neighbor);
- mutex_unlock(&path.dentry->d_inode->i_mutex);
- dput(dentry);
path_put(&path);
}
-
return ret;
}
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