The patch titled
tty: Fix bits and note more bits to fix
has been added to the -mm tree. Its filename is
tty-fix-bits-and-note-more-bits-to-fix.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: tty: Fix bits and note more bits to fix
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
If your driver implements "break on" and "break off" this ensures you won't
get multiple overlapping requests or requests in parallel. If your driver
has its own break handling then its still your problem as the driver
author.
Break is also now serialized against writes from user space properly but no
new guarantees are made driver level about writes from the line discipline
itself (eg flow control or echo)
Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/char/tty_io.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff -puN drivers/char/tty_io.c~tty-fix-bits-and-note-more-bits-to-fix drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~tty-fix-bits-and-note-more-bits-to-fix
+++ a/drivers/char/tty_io.c
@@ -2718,6 +2718,8 @@ static int tty_fasync(int fd, struct fil
* Locking:
* Called functions take tty_ldisc_lock
* current->signal->tty check is safe without locks
+ *
+ * FIXME: may race normal receive processing
*/
static int tiocsti(struct tty_struct *tty, char __user *p)
@@ -2877,9 +2879,7 @@ static int fionbio(struct file *file, in
* Locking:
* Takes tasklist lock internally to walk sessions
* Takes task_lock() when updating signal->tty
- *
- * FIXME: tty_mutex is needed to protect signal->tty references.
- * FIXME: why task_lock on the signal->tty reference ??
+ * Takes tty_mutex() to protect tty instance
*
*/
@@ -2914,9 +2914,11 @@ static int tiocsctty(struct tty_struct *
} else
return -EPERM;
}
+ mutex_lock(&tty_mutex);
task_lock(current);
current->signal->tty = tty;
task_unlock(current);
+ mutex_unlock(&tty_mutex);
current->signal->tty_old_pgrp = 0;
tty->session = current->signal->session;
tty->pgrp = process_group(current);
@@ -2956,8 +2958,6 @@ static int tiocgpgrp(struct tty_struct *
* permitted where the tty session is our session.
*
* Locking: None
- *
- * FIXME: current->signal->tty referencing is unsafe.
*/
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -3036,19 +3036,20 @@ static int tiocsetd(struct tty_struct *t
* timed break functionality.
*
* Locking:
- * None
+ * atomic_write_lock serializes
*
- * FIXME:
- * What if two overlap
*/
static int send_break(struct tty_struct *tty, unsigned int duration)
{
+ if (mutex_lock_interruptible(&tty->atomic_write_lock))
+ return -EINTR;
tty->driver->break_ctl(tty, -1);
if (!signal_pending(current)) {
msleep_interruptible(duration);
}
tty->driver->break_ctl(tty, 0);
+ mutex_unlock(&tty->atomic_write_lock);
if (signal_pending(current))
return -EINTR;
return 0;
@@ -3141,6 +3142,8 @@ int tty_ioctl(struct inode * inode, stru
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
return -EINVAL;
+ /* CHECKME: is this safe as one end closes ? */
+
real_tty = tty;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
_
Patches currently in -mm which might be from alan@xxxxxxxxxxxxxxxxxxx are
origin.patch
tty-remove-bogus-call-to-cdev_del.patch
tty-layer-comment-the-locking-assumptions-and-functions.patch
fix-tty-layer-dos-and-comment-relevant-code.patch
git-libata-all.patch
libata-add-40pin-short-cable-support-honour-drive.patch
1-of-2-jmicron-driver.patch
1-of-2-jmicron-driver-hard_port_no-fix.patch
2-of-2-jmicron-driver-plumbing-and-quirk.patch
non-libata-driver-for-jmicron-devices.patch
via-pata-controller-xfer-fixes.patch
megaraid-gcc-41-warning-fix.patch
voyager-tty-locking.patch
edac-new-opteron-athlon64-memory-controller-driver.patch
edac-new-opteron-athlon64-memory-controller-driver-tidy.patch
sanitize-3c589_cs.patch
make-prot_write-imply-prot_read.patch
sgiioc4-fixup-use-of-mmio-ops.patch
remove-unused-tty_struct-variable.patch
there-is-no-devfs-there-has-never-been-a-devfs-we-have.patch
tty-locking-on-resize.patch
ahci-ati-sb600-sata-support-for-various-modes.patch
atiixp-ati-sb600-ide-support-for-various-modes.patch
dquot-add-proper-locking-when-using-current-signal-tty.patch
tty-trivial-kzalloc-opportunity.patch
tty-lock-ticogwinsz.patch
tty-stop-the-tty-vanishing-under-procfs-access.patch
exit-fix-crash-case.patch
tty-make-termios_sem-a-mutex.patch
tty-make-termios_sem-a-mutex-fix.patch
solaris-emulation-incorrect-tty-locking.patch
tty-fix-bits-and-note-more-bits-to-fix.patch
support-piping-into-commands-in-proc-sys-kernel-core_pattern.patch
ide-claim-extra-dma-ports-regardless-of-channel.patch
ide-always-release-dma-engine.patch
ide-error-handling-fixes.patch
ide-hpt3xxn-clocking-fixes.patch
ide-fix-hpt37x-timing-tables.patch
ide-optimize-hpt37x-timing-tables.patch
ide-fix-hpt3xx-hotswap-support.patch
ide-fix-the-case-of-multiple-hpt3xx-chips-present.patch
ide-hpt3xx-fix-pci-clock-detection.patch
ide-hpt3xx-fix-pci-clock-detection-fix-2.patch
piix-fix-82371mx-enablebits.patch
piix-remove-check-for-broken-mw-dma-mode-0.patch
piix-slc90e66-pio-mode-fallback-fix.patch
make-number-of-ide-interfaces-configurable.patch
ide_dma_speed-fixes.patch
hpt3xx-rework-rate-filtering.patch
hpt3xx-rework-rate-filtering-tidy.patch
hpt3xx-print-the-real-chip-name-at-startup.patch
hpt3xx-switch-to-using-pci_get_slot.patch
hpt3xx-cache-channels-mcr-address.patch
hpt3x7-merge-speedproc-handlers.patch
hpt370-clean-up-dma-timeout-handling.patch
enable-cdrom-dma-access-with-pdc20265_old.patch
ide-fix-revision-comparison-in-ide_in_drive_list.patch
ide-backport-piix-fixes-from-libata-into-the-legacy-driver.patch
hpt3xx-init-code-rewrite.patch
move-ide-to-unmaintained-drop-reference-to-old-git-tree.patch
drivers-ide-cleanups.patch
ide-remove-dma_base2-field-from-ide_hwif_t.patch
ide-reprogram-disk-pio-timings-on-resume.patch
asus-mv-ide-device-ids.patch
ide-support-for-via-8237a-southbridge.patch
config_pm=n-slim-drivers-ide-pci-sc1200c.patch
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