Hi,
On Thursday 12 March 2009, Stephen Rothwell wrote:
> Hi all,
>
> Changes since 20090311:
It fails to boot here (both with QEMU and the real hardware):
...
Warning: unable to open an initial console.
Kernel panic - not syncing: Attempted to kill init!
...
I bisected the problem to:
>From 31f8326f981117fc548d292656fa8dbed28bc42b Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Date: Thu, 12 Mar 2009 10:00:15 +1100
Subject: [PATCH] tty-fix-mismatch-in-lookup-han
The lookup methods return NULL or a pointer. The caller expects an ERR_PTR.
It seems to make sense to just use NULL and return -ENODEV here as it keeps
the code simple and clean and the way it always used to work (effectively)
before the restructure
Problem noticed by Jiri Slaby.
Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/tty_io.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index bc84e12..0cc0c60 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1817,9 +1817,9 @@ got_driver:
/* check whether we're reopening an existing tty */
tty = tty_driver_lookup_tty(driver, inode, index);
- if (IS_ERR(tty)) {
+ if (tty == NULL) {
mutex_unlock(&tty_mutex);
- return PTR_ERR(tty);
+ return -ENODEV;
}
}
--
It seems that fixing IS_ERR() check uncovered some underlying problem
since we are later checking for tty == NULL in __tty_open().
The following patch fixes the issue for me (Alan, feel free to merge
it back into your tty-fix-mismatch-in-lookup-han patch or replace by
a more complete __tty_open() reorganization):
From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Subject: [PATCH] tty: fix __tty_open()
On tty_driver_lookup_tty() failure __tty_open() should continue
instead of returning an error, fix it.
Also update tty_driver_lookup_tty() documentation while at it.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
---
drivers/char/tty_io.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
Index: b/drivers/char/tty_io.c
===================================================================
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1205,7 +1205,7 @@ static void tty_line_name(struct tty_dri
* @driver: the driver for the tty
* @idx: the minor number
*
- * Return the tty, if found or ERR_PTR() otherwise.
+ * Return the tty, if found or NULL otherwise.
*
* Locking: tty_mutex must be held. If tty is found, the mutex must
* be held until the 'fast-open' is also done. Will change once we
@@ -1813,16 +1813,10 @@ retry_open:
return -ENODEV;
}
got_driver:
- if (!tty) {
+ if (!tty)
/* check whether we're reopening an existing tty */
tty = tty_driver_lookup_tty(driver, inode, index);
- if (tty == NULL) {
- mutex_unlock(&tty_mutex);
- return -ENODEV;
- }
- }
-
if (tty) {
retval = tty_reopen(tty);
if (retval)
--
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