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Commit 9b4f526c authored by Al Viro's avatar Al Viro
Browse files

[PATCH] proc_readfd_common() race fix 



Since we drop the rcu_read_lock inside the loop, we can't assume
that files->fdt will remain unchanged (and not freed) between
iterations.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ed152437

fs/proc/base.c

+1 −3
Original line number Diff line number Diff line
@@ -1626,7 +1626,6 @@ static int proc_readfd_common(struct file * filp, void * dirent, 
	unsigned int fd, ino;

	int retval;

	struct files_struct * files;

	struct fdtable *fdt;



	retval = -ENOENT;

	if (!p)
@@ -1649,9 +1648,8 @@ static int proc_readfd_common(struct file * filp, void * dirent, 
			if (!files)

				goto out;

			rcu_read_lock();

			fdt = files_fdtable(files);

			for (fd = filp->f_pos-2;

			     fd < fdt->max_fds;

			     fd < files_fdtable(files)->max_fds;

			     fd++, filp->f_pos++) {

				char name[PROC_NUMBUF];

				int len;