diff options
Diffstat (limited to 'fs/fcntl.c')
| -rw-r--r-- | fs/fcntl.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index bfecc6238083..d2f3ed8acd93 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -16,6 +16,7 @@ #include <linux/security.h> #include <linux/ptrace.h> #include <linux/signal.h> +#include <linux/rcupdate.h> #include <asm/poll.h> #include <asm/siginfo.h> @@ -64,8 +65,8 @@ static int locate_fd(struct files_struct *files, if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) goto out; - fdt = files_fdtable(files); repeat: + fdt = files_fdtable(files); /* * Someone might have closed fd's in the range * orig_start..fdt->next_fd @@ -95,9 +96,15 @@ repeat: if (error) goto repeat; + /* + * We reacquired files_lock, so we are safe as long as + * we reacquire the fdtable pointer and use it while holding + * the lock, no one can free it during that time. + */ + fdt = files_fdtable(files); if (start <= fdt->next_fd) fdt->next_fd = newfd + 1; - + error = newfd; out: @@ -163,7 +170,7 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) if (!tofree && FD_ISSET(newfd, fdt->open_fds)) goto out_fput; - fdt->fd[newfd] = file; + rcu_assign_pointer(fdt->fd[newfd], file); FD_SET(newfd, fdt->open_fds); FD_CLR(newfd, fdt->close_on_exec); spin_unlock(&files->file_lock); |