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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-04 17:18:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-10 09:27:56 +0100 |
| commit | c776b77a279c327fe9e7710e71a3400766554255 (patch) | |
| tree | 02479c6cabaa846b78332e0bf5202b79b9625ae5 /drivers | |
| parent | 2334de198fed3da72e9785ecdd691d101aa96e77 (diff) | |
| download | linux-rpi-c776b77a279c327fe9e7710e71a3400766554255.tar.gz linux-rpi-c776b77a279c327fe9e7710e71a3400766554255.tar.bz2 linux-rpi-c776b77a279c327fe9e7710e71a3400766554255.zip | |
Revert "drivers:tty:pty: Fix a race causing data loss on close"
This reverts commit 33d4ae98859873ddd49e22e4ca724387548b3d89.
Pierre-Louis writes:
Our SOF/audio CI shows an across-the-board regression when we try v5.12-rc1,
specifically on pause/resume tests with an interactive terminal running 'aplay
-i' commands managed by expect to simulate the user pressing the space bar to
pause/unpause. It turns out the processes are not longer killed and the audio
devices remain busy (see publicly available test results listed below).
git bisect points to commit 33d4ae9885987 ("drivers:tty:pty: Fix a race
causing data loss on close"). Reverting the patch fixes the issue on all test
devices.
Further analysis with Corey Minyard points to a problem where a slave tty will
not get a SIGHUP when the master is closed.
So revert this for now:
Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/00154592-c5ee-aaba-956e-b265473b53bc@linux.intel.com
Cc: Corey Minyard <cminyard@mvista.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mark Brown <broonie@kernel.org>,
Fixes: 33d4ae988598 ("drivers:tty:pty: Fix a race causing data loss on close")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/pty.c | 15 | ||||
| -rw-r--r-- | drivers/tty/tty_io.c | 5 |
2 files changed, 4 insertions, 16 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 8b2797b6ee44..5e2374580e27 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -66,8 +66,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp) wake_up_interruptible(&tty->link->read_wait); wake_up_interruptible(&tty->link->write_wait); if (tty->driver->subtype == PTY_TYPE_MASTER) { - struct file *f; - + set_bit(TTY_OTHER_CLOSED, &tty->flags); #ifdef CONFIG_UNIX98_PTYS if (tty->driver == ptm_driver) { mutex_lock(&devpts_mutex); @@ -76,17 +75,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp) mutex_unlock(&devpts_mutex); } #endif - - /* - * This hack is required because a program can open a - * pty and redirect a console to it, but if the pty is - * closed and the console is not released, then the - * slave side will never close. So release the - * redirect when the master closes. - */ - f = tty_release_redirect(tty->link); - if (f) - fput(f); + tty_vhangup(tty->link); } } diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 74733ec8f565..391bada4cedb 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -544,9 +544,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup); * @tty: tty device * * This is available to the pty code so if the master closes, if the - * slave is a redirect it can release the redirect. It returns the - * filp for the redirect, which must be fput when the operations on - * the tty are completed. + * slave is a redirect it can release the redirect. */ struct file *tty_release_redirect(struct tty_struct *tty) { @@ -561,6 +559,7 @@ struct file *tty_release_redirect(struct tty_struct *tty) return f; } +EXPORT_SYMBOL_GPL(tty_release_redirect); /** * __tty_hangup - actual handler for hangup events |