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Commit 4fb3a538 authored by Dipankar Sarma's avatar Dipankar Sarma Committed by Linus Torvalds
Browse files

[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: default avatarDipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent af4e5a21

arch/alpha/kernel/osf_sys.c

+6 −1
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/namei.h>

#include <linux/uio.h>

#include <linux/vfs.h>

#include <linux/rcupdate.h>



#include <asm/fpu.h>

#include <asm/io.h>
@@ -975,6 +976,7 @@ osf_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, 
	long timeout;

	int ret = -EINVAL;

	struct fdtable *fdt;

	int max_fdset;



	timeout = MAX_SCHEDULE_TIMEOUT;

	if (tvp) {
@@ -996,8 +998,11 @@ osf_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, 
		}

	}



	rcu_read_lock();

	fdt = files_fdtable(current->files);

	if (n < 0 || n > fdt->max_fdset)

	max_fdset = fdt->max_fdset;

	rcu_read_unlock();

	if (n < 0 || n > max_fdset)

		goto out_nofds;



	/*

arch/ia64/kernel/perfmon.c

+2 −1
Original line number Diff line number Diff line
@@ -2218,12 +2218,13 @@ static void 
pfm_free_fd(int fd, struct file *file)

{

	struct files_struct *files = current->files;

	struct fdtable *fdt = files_fdtable(files);

	struct fdtable *fdt;



	/* 

	 * there ie no fd_uninstall(), so we do it here

	 */

	spin_lock(&files->file_lock);

	fdt = files_fdtable(files);

	rcu_assign_pointer(fdt->fd[fd], NULL);

	spin_unlock(&files->file_lock);

fs/locks.c

+3 −0
Original line number Diff line number Diff line
@@ -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 @@ void steal_locks(fl_owner_t from) 


	lock_kernel();

	j = 0;

	rcu_read_lock();

	fdt = files_fdtable(files);

	for (;;) {

		unsigned long set;
@@ -2222,6 +2224,7 @@ void steal_locks(fl_owner_t from) 
			set >>= 1;

		}

	}

	rcu_read_unlock();

	unlock_kernel();

}

EXPORT_SYMBOL(steal_locks);

fs/proc/array.c

+3 −0
Original line number Diff line number Diff line
@@ -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 @@ static inline char * task_state(struct task_struct *p, char *buffer) 
		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);

kernel/exit.c

+6 −0
Original line number Diff line number Diff line
@@ -371,6 +371,12 @@ static inline void close_files(struct files_struct * files) 
	struct fdtable *fdt;



	j = 0;



	/*

	 * It is safe to dereference the fd table without RCU or

	 * ->file_lock because this is the last reference to the

	 * files structure.

	 */

	fdt = files_fdtable(files);

	for (;;) {

		unsigned long set;