T Taneli Vahakangas <vahakang@cs.helsinki.fi> reported that
commit 786d7e1612f0b0adb6046f19b906609e4fe8b1ba aka
"Fix rmmod/read/write races in /proc entries"
broke SBCL + SLIME combo.
Old code in do_select() used DEFAULT_POLLMASK, if couldn't find ->poll
handler. New code makes ->poll always there and returns 0 by default,
which is not correct. Return DEFAULT_POLLMASK instead.
Steps to reproduce:
install emacs, SBCL, SLIME
emacs
M-x slime in *inferior-lisp* buffer
[watch it doing "Connecting to Swank on port X.."]
Please, apply before 2.6.23.
P.S.: why SBCL can't just read(2) /proc/cpuinfo is a mystery.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/proc/inode.c | 3 ++-
fs/select.c | 2 --
include/linux/poll.h | 2 ++
3 files changed, 4 insertions(+), 3 deletions(-)
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -11,6 +11,7 @@
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/completion.h>
+#include <linux/poll.h>
#include <linux/file.h>
#include <linux/limits.h>
#include <linux/init.h>
@@ -232,7 +233,7 @@ static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t
static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
{
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
- unsigned int rv = 0;
+ unsigned int rv = DEFAULT_POLLMASK;
unsigned int (*poll)(struct file *, struct poll_table_struct *);
spin_lock(&pde->pde_unload_lock);
--- a/fs/select.c
+++ b/fs/select.c
@@ -26,8 +26,6 @@
#include <asm/uaccess.h>
-#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
-
struct poll_table_page {
struct poll_table_page * next;
struct poll_table_entry * entry;
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -21,6 +21,8 @@
#define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
#define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
+#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
+
struct poll_table_struct;
/*
-
