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more patches for this tty open race

This commit is contained in:
Kyle McMartin 2010-11-27 10:30:59 -05:00
parent ea17f5cd11
commit dadc63b854
3 changed files with 135 additions and 1 deletions
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6
kernel.spec
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@ -51,7 +51,7 @@ Summary: The Linux kernel
# For non-released -rc kernels, this will be prepended with "0.", so
# for example a 3 here will become 0.3
#
%global baserelease 1
%global baserelease 2
%global fedora_build %{baserelease}
# base_sublevel is the kernel version we're starting with and patching
@ -701,6 +701,8 @@ Patch12303: dmar-disable-when-ricoh-multifunction.patch
Patch12400: tty-dont-allow-reopen-when-ldisc-is-changing.patch
Patch12401: debug-tty-print-dev-name.patch
Patch12402: tty-ldisc-fix-open-flag-handling.patch
Patch12403: tty-open-hangup-race-fixup.patch
%endif
@ -1293,6 +1295,8 @@ ApplyPatch dmar-disable-when-ricoh-multifunction.patch
# rhbz#630464
ApplyPatch tty-dont-allow-reopen-when-ldisc-is-changing.patch
ApplyPatch debug-tty-print-dev-name.patch
ApplyPatch tty-ldisc-fix-open-flag-handling.patch
ApplyPatch tty-open-hangup-race-fixup.patch
# END OF PATCH APPLICATIONS

54
tty-ldisc-fix-open-flag-handling.patch Normal file
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@ -0,0 +1,54 @@
From linux-kernel-owner@vger.kernel.org Wed Nov 24 18:28:11 2010
From: Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH 1/2] TTY: ldisc, fix open flag handling
Date: Thu, 25 Nov 2010 00:27:54 +0100
When a concrete ldisc open fails in tty_ldisc_open, we forget to clear
TTY_LDISC_OPEN. This causes a false warning on the next ldisc open:
WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38()
Hardware name: System Product Name
Modules linked in: ...
Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1
Call Trace:
[<c1030321>] ? warn_slowpath_common+0x5e/0x8a
[<c1030357>] ? warn_slowpath_null+0xa/0xc
[<c119311c>] ? tty_ldisc_open+0x26/0x38
[<c11936c5>] ? tty_set_ldisc+0x218/0x304
...
So clear the bit when failing...
Introduced in c65c9bc3efa (tty: rewrite the ldisc locking) back in
2.6.31-rc1.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Reported-by: Sergey Lapin <slapin@ossfans.org>
Tested-by: Sergey Lapin <slapin@ossfans.org>
---
drivers/tty/tty_ldisc.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index d8e96b0..4214d58 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -454,6 +454,8 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
/* BTM here locks versus a hangup event */
WARN_ON(!tty_locked());
ret = ld->ops->open(tty);
+ if (ret)
+ clear_bit(TTY_LDISC_OPEN, &tty->flags);
return ret;
}
return 0;
--
1.7.3.1
--
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76
tty-open-hangup-race-fixup.patch Normal file
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@ -0,0 +1,76 @@
From 9e88e8b9915b5e067507a087437d80e6a133d612 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Sat, 27 Nov 2010 16:06:46 +0100
Subject: [PATCH 1/1] TTY: open/hangup race fixup
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/tty_io.c | 10 +++++++++-
include/linux/tty.h | 1 +
2 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 878f6d6..35480dd 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -559,6 +559,9 @@ void __tty_hangup(struct tty_struct *tty)
tty_lock();
+ /* some functions below drop BTM, so we need this bit */
+ set_bit(TTY_HUPPING, &tty->flags);
+
/* inuse_filps is protected by the single tty lock,
this really needs to change if we want to flush the
workqueue with the lock held */
@@ -578,6 +581,10 @@ void __tty_hangup(struct tty_struct *tty)
}
spin_unlock(&tty_files_lock);
+ /*
+ * it drops BTM and thus races with reopen
+ * we protect the race by TTY_HUPPING
+ */
tty_ldisc_hangup(tty);
read_lock(&tasklist_lock);
@@ -615,7 +622,6 @@ void __tty_hangup(struct tty_struct *tty)
tty->session = NULL;
tty->pgrp = NULL;
tty->ctrl_status = 0;
- set_bit(TTY_HUPPED, &tty->flags);
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
/* Account for the p->signal references we killed */
@@ -641,6 +647,7 @@ void __tty_hangup(struct tty_struct *tty)
* can't yet guarantee all that.
*/
set_bit(TTY_HUPPED, &tty->flags);
+ clear_bit(TTY_HUPPING, &tty->flags);
tty_ldisc_enable(tty);
tty_unlock();
@@ -1311,6 +1318,7 @@ static int tty_reopen(struct tty_struct *tty)
struct tty_driver *driver = tty->driver;
if (test_bit(TTY_CLOSING, &tty->flags) ||
+ test_bit(TTY_HUPPING, &tty->flags) ||
test_bit(TTY_LDISC_CHANGING, &tty->flags))
return -EIO;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 032d79f..54e4eaa 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -366,6 +366,7 @@ struct tty_file_private {
#define TTY_HUPPED 18 /* Post driver->hangup() */
#define TTY_FLUSHING 19 /* Flushing to ldisc in progress */
#define TTY_FLUSHPENDING 20 /* Queued buffer flush pending */
+#define TTY_HUPPING 21 /* ->hangup() in progress */
#define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
--
1.7.3.1