Hi,
I found that kernel 2.5.73 (and also 2.4.21) crashed
in drivers/char/tty_io.c at situation described below.
1. login to tty2 (not tty1)
2. start kon (Kanji cONsole emulator, console which support
Japanese characters)
3. exit kon
4. logout
This crash is repeatable.
I use Redhat 9 on ThinkPad T20.
These patches (for kernel 2.5.73 and 2.4.21) prevent list_del() when
the list is empty.
In kernel 2.5.73, these applying list_del() to empty list
seems to be occured very often (not only at the above situation).
I think this might be harmful.
Regards,
Hiroshi Inoue
--- /usr/src/linux-2.5.73.orig/drivers/char/tty_io.c 2003-06-25 10:45:30.000000000 +0900
+++ /usr/src/linux-2.5.73/drivers/char/tty_io.c 2003-06-27 00:17:12.000000000 +0900
@@ -1018,9 +1018,11 @@
}
o_tty->magic = 0;
o_tty->driver->refcount--;
- file_list_lock();
- list_del(&o_tty->tty_files);
- file_list_unlock();
+ if (o_tty->tty_files.next != &o_tty->tty_files) {
+ file_list_lock();
+ list_del(&o_tty->tty_files);
+ file_list_unlock();
+ }
free_tty_struct(o_tty);
}
@@ -1032,9 +1034,11 @@
}
tty->magic = 0;
tty->driver->refcount--;
- file_list_lock();
- list_del(&tty->tty_files);
- file_list_unlock();
+ if (tty->tty_files.next != &tty->tty_files) {
+ file_list_lock();
+ list_del(&tty->tty_files);
+ file_list_unlock();
+ }
module_put(tty->driver->owner);
free_tty_struct(tty);
}
@@ -1372,7 +1376,10 @@
}
filp->private_data = tty;
- file_move(filp, &tty->tty_files);
+ if (filp->f_list.next == &filp->f_list)
+ list_add(&filp->f_list, &tty->tty_files);
+ else
+ file_move(filp, &tty->tty_files);
check_tty_count(tty, "tty_open");
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
--- /usr/src/linux-2.4.21.orig/drivers/char/tty_io.c 2003-06-13 23:51:33.000000000 +0900
+++ /usr/src/linux-2.4.21/drivers/char/tty_io.c 2003-06-27 00:34:53.798982568 +0900
@@ -1043,7 +1043,8 @@
}
o_tty->magic = 0;
(*o_tty->driver.refcount)--;
- list_del(&o_tty->tty_files);
+ if (o_tty->tty_files.next != &o_tty->tty_files)
+ list_del(&o_tty->tty_files);
free_tty_struct(o_tty);
}
@@ -1055,7 +1056,8 @@
}
tty->magic = 0;
(*tty->driver.refcount)--;
- list_del(&tty->tty_files);
+ if (tty->tty_files.next != &tty->tty_files)
+ list_del(&tty->tty_files);
free_tty_struct(tty);
}
@@ -1383,7 +1385,10 @@
init_dev_done:
#endif
filp->private_data = tty;
- file_move(filp, &tty->tty_files);
+ if (filp->f_list.next == &filp->f_list)
+ list_add(&filp->f_list, &tty->tty_files);
+ else
+ file_move(filp, &tty->tty_files);
check_tty_count(tty, "tty_open");
if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
tty->driver.subtype == PTY_TYPE_MASTER)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jun 30 2003 - 22:00:24 EST