From dd23aae4f5edf4e1dbd8f7f8013a754ba3253f48 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 11 Sep 2007 15:23:55 -0700 Subject: [PATCH] Fix select on /proc files without ->poll MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Taneli Vähäkangas reported that commit 786d7e1612f0b0adb6046f19b906609e4fe8b1ba aka "Fix rmmod/read/write races in /proc entries" broke SBCL + SLIME combo. The old code in do_select() used DEFAULT_POLLMASK, if couldn't find ->poll handler. The 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 Cc: T Taneli Vahakangas Cc: Oleg Nesterov Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/inode.c | 3 ++- fs/select.c | 2 -- include/linux/poll.h | 2 ++ 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index a5b0dfd89a17..0e4d37c93eea 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/fs/select.c b/fs/select.c index a974082b0824..46dca31c607a 100644 --- a/fs/select.c +++ b/fs/select.c @@ -26,8 +26,6 @@ #include -#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) - struct poll_table_page { struct poll_table_page * next; struct poll_table_entry * entry; diff --git a/include/linux/poll.h b/include/linux/poll.h index 27690798623f..16d813b364ef 100644 --- 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; /* -- 2.20.1