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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2008-04-30 03:53:30 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 11:29:40 -0400
commit47f86834bbd4193139d61d659bebf9ab9d691e37 (patch)
tree6724b07e24929eba5c6df31f07871d9d6b4aa296 /include/linux/tty.h
parent04f378b198da233ca0aca341b113dc6579d46123 (diff)
redo locking of tty->pgrp
Historically tty->pgrp and friends were pid_t and the code "knew" they were safe. The change to pid structs opened up a few races and the removal of the BKL in places made them quite hittable. We put tty->pgrp under the ctrl_lock for the tty. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/tty.h')
-rw-r--r--include/linux/tty.h10
1 files changed, 6 insertions, 4 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 4d3702bade03..381085e45cca 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -184,21 +184,22 @@ struct tty_struct {
184 struct tty_ldisc ldisc; 184 struct tty_ldisc ldisc;
185 struct mutex termios_mutex; 185 struct mutex termios_mutex;
186 spinlock_t ctrl_lock; 186 spinlock_t ctrl_lock;
187 /* Termios values are protected by the termios mutex */
187 struct ktermios *termios, *termios_locked; 188 struct ktermios *termios, *termios_locked;
188 char name[64]; 189 char name[64];
189 struct pid *pgrp; 190 struct pid *pgrp; /* Protected by ctrl lock */
190 struct pid *session; 191 struct pid *session;
191 unsigned long flags; 192 unsigned long flags;
192 int count; 193 int count;
193 struct winsize winsize; 194 struct winsize winsize; /* termios mutex */
194 unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1; 195 unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
195 unsigned char low_latency:1, warned:1; 196 unsigned char low_latency:1, warned:1;
196 unsigned char ctrl_status; 197 unsigned char ctrl_status; /* ctrl_lock */
197 unsigned int receive_room; /* Bytes free for queue */ 198 unsigned int receive_room; /* Bytes free for queue */
198 199
199 struct tty_struct *link; 200 struct tty_struct *link;
200 struct fasync_struct *fasync; 201 struct fasync_struct *fasync;
201 struct tty_bufhead buf; 202 struct tty_bufhead buf; /* Locked internally */
202 int alt_speed; /* For magic substitution of 38400 bps */ 203 int alt_speed; /* For magic substitution of 38400 bps */
203 wait_queue_head_t write_wait; 204 wait_queue_head_t write_wait;
204 wait_queue_head_t read_wait; 205 wait_queue_head_t read_wait;
@@ -212,6 +213,7 @@ struct tty_struct {
212 /* 213 /*
213 * The following is data for the N_TTY line discipline. For 214 * The following is data for the N_TTY line discipline. For
214 * historical reasons, this is included in the tty structure. 215 * historical reasons, this is included in the tty structure.
216 * Mostly locked by the BKL.
215 */ 217 */
216 unsigned int column; 218 unsigned int column;
217 unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; 219 unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;