Adam Litke <[EMAIL PROTECTED]> writes:
> Hey. While testing 2.6.21-rc2 with libhugetlbfs, the shm-fork test case
> causes the kernel to oops. To reproduce: Execute 'make check' in the
> latest libhugetlbfs source on a 2.6.21-rc2 kernel with 100 huge pages
> allocated. Using fewer huge pages will likely also trigger the oops.
> Libhugetlbfs can be downloaded from:
> http://libhugetlbfs.ozlabs.org/snapshots/libhugetlbfs-dev-20070228.tar.gz
>
> I have collected the following information:
Thanks. I'm going to be offline starting early tomorrow so I'm
unfortunately not going to be timely in tracing this one down.
Ok. Looking at the code I have a clue what is going on. I think
I must have been out of it the day I wrote this patch. I don't have
fsync or get_unmapped_area methods appropriately wrapped. I clearly
did not do a close audit of the filesystem methods that hugetlbfs
inodes use. I may have just gotten luck on other architectures.
get_unmapped_area looks like it will be a bit of a trick.
If it is just failing to wrap the methods a couple of file methods
then the patch below should fix it or come close. That's the best
I can do before I leave.
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index a60995a..44f1f05 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -168,7 +168,9 @@ void hugetlb_put_quota(struct address_space *mapping);
static inline int is_file_hugepages(struct file *file)
{
- return file->f_op == &hugetlbfs_file_operations;
+ return (file->f_op == &hugetlbfs_file_operations) ||
+ is_file_shm_hugepages(file);
+
}
static inline void set_file_hugepages(struct file *file)
diff --git a/include/linux/shm.h b/include/linux/shm.h
index a2c896a..ad2e3af 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -96,12 +96,17 @@ struct shmid_kernel /* private to the kernel */
#ifdef CONFIG_SYSVIPC
long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long
*addr);
+extern int is_file_shm_hugepages(struct file *file);
#else
static inline long do_shmat(int shmid, char __user *shmaddr,
int shmflg, unsigned long *addr)
{
return -ENOSYS;
}
+static inline int is_file_shm_hugepages(struct file *file)
+{
+ return 0;
+}
#endif
#endif /* __KERNEL__ */
diff --git a/ipc/shm.c b/ipc/shm.c
index 26b935b..93cfa35 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -235,7 +235,7 @@ struct page *shm_nopage(struct vm_area_struct *vma,
unsigned long address, int *
}
#ifdef CONFIG_NUMA
-int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
+static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
@@ -245,7 +245,7 @@ int shm_set_policy(struct vm_area_struct *vma, struct
mempolicy *new)
return err;
}
-struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long
addr)
+static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned
long addr)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
@@ -284,21 +284,41 @@ static int shm_release(struct inode *ino, struct file
*file)
return 0;
}
-#ifndef CONFIG_MMU
+static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+ int (*fsync) (struct file *, struct dentry *, int datasync);
+ struct shm_file_data *sfd;
+ int ret;
+ ret = -EINVAL;
+ sfd = shm_file_data(file);
+ fsync = sfd->file->f_op->fsync;
+ if (fsync)
+ ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
+ return ret;
+}
+
static unsigned long shm_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct shm_file_data *sfd = shm_file_data(file);
- return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, pgoff,
- flags);
+ return get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+int is_file_shm_hugepages(struct file *file)
+{
+ int ret = 0;
+ if (file->f_op == &shm_file_operations) {
+ struct shm_file_data *sfd;
+ sfd = shm_file_data(file);
+ ret = is_file_hugepages(file);
+ }
+ return ret;
}
-#else
-#define shm_get_unmapped_area NULL
-#endif
static struct file_operations shm_file_operations = {
.mmap = shm_mmap,
+ .fsync = shm_fsync,
.release = shm_release,
.get_unmapped_area = shm_get_unmapped_area,
};
-
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