[PATCH] files: fix preemption issues
With the new fdtable locking rules, you have to protect fdtable with either
->file_lock or rcu_read_lock/unlock(). There are some places where we
aren't doing either. This patch fixes those places.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/locks.c b/fs/locks.c
index c2c09b4..f7daa5f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -124,6 +124,7 @@
#include <linux/smp_lock.h>
#include <linux/syscalls.h>
#include <linux/time.h>
+#include <linux/rcupdate.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
@@ -2205,6 +2206,7 @@
lock_kernel();
j = 0;
+ rcu_read_lock();
fdt = files_fdtable(files);
for (;;) {
unsigned long set;
@@ -2222,6 +2224,7 @@
set >>= 1;
}
}
+ rcu_read_unlock();
unlock_kernel();
}
EXPORT_SYMBOL(steal_locks);
diff --git a/fs/proc/array.c b/fs/proc/array.c
index d88d518..d84eeca 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -74,6 +74,7 @@
#include <linux/file.h>
#include <linux/times.h>
#include <linux/cpuset.h>
+#include <linux/rcupdate.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
@@ -180,12 +181,14 @@
p->gid, p->egid, p->sgid, p->fsgid);
read_unlock(&tasklist_lock);
task_lock(p);
+ rcu_read_lock();
if (p->files)
fdt = files_fdtable(p->files);
buffer += sprintf(buffer,
"FDSize:\t%d\n"
"Groups:\t",
fdt ? fdt->max_fds : 0);
+ rcu_read_unlock();
group_info = p->group_info;
get_group_info(group_info);