kernel.git/drivers/tty/tty_io.c, branch linux-5.13.y

tty: Fix data race between tiocsti() and flush_to_ldisc()

2021-09-15T08:00:56Z

commit bb2853a6a421a052268eee00fd5d3f6b3504b2b1 upstream. The ops->receive_buf() may be accessed concurrently from these two functions. If the driver flushes data to the line discipline receive_buf() method while tiocsti() is waiting for the ops->receive_buf() to finish its work, the data race will happen. For example: tty_ioctl |tty_ldisc_receive_buf ->tioctsi | ->tty_port_default_receive_buf | ->tty_ldisc_receive_buf ->hci_uart_tty_receive | ->hci_uart_tty_receive ->h4_recv | ->h4_recv In this case, the h4 receive buffer will be overwritten by the latecomer, and we will lost the data. Hence, change tioctsi() function to use the exclusive lock interface from tty_buffer to avoid the data race. Reported-by: syzbot+97388eb9d31b997fe1d0@syzkaller.appspotmail.com Reviewed-by: Jiri Slaby Signed-off-by: Nguyen Dinh Phi Link: https://lore.kernel.org/r/20210823000641.2082292-1-phind.uet@gmail.com Cc: stable Signed-off-by: Greg Kroah-Hartman

tty: make tty_release_redirect() static

2021-04-15T08:28:30Z

No one calls this outside of the tty_io.c file, so mark this static and do not export the symbol anymore. Cc: Jiri Slaby Link: https://lore.kernel.org/r/20210408125134.3016837-11-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

tty: create internal tty.h file

2021-04-15T08:22:17Z

There are a number of functions and #defines in include/linux/tty.h that do not belong there as they are private to the tty core code. Create an initial drivers/tty/tty.h file and copy the odd "tty logging" macros into it to seed the file with some initial things that we know nothing outside of the tty core should be calling. Cc: Tetsuo Handa Cc: Jiri Slaby Link: https://lore.kernel.org/r/20210408125134.3016837-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

tty: refactor TIOCSSERIAL handling

2021-04-10T08:36:34Z

Factor out the deprecated serial flags handling and tty-operation check shared with the compat TIOCSSERIAL handler. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407095208.31838-6-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: use pr_warn_ratelimited() for deprecated serial flags

2021-04-10T08:36:34Z

Use pr_warn_ratelimited() when warning about deprecated serial flags instead of open coding. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407095208.31838-5-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: fix return value for unsupported ioctls

2021-04-10T08:36:34Z

Drivers should return -ENOTTY ("Inappropriate I/O control operation") when an ioctl isn't supported, while -EINVAL is used for invalid arguments. Fix up the TIOCMGET, TIOCMSET and TIOCGICOUNT helpers which returned -EINVAL when a tty driver did not implement the corresponding operations. Note that the TIOCMGET and TIOCMSET helpers predate git and do not get a corresponding Fixes tag below. Fixes: d281da7ff6f7 ("tty: Make tiocgicount a handler") Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407095208.31838-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

Merge 5.12-rc3 into tty-next

2021-03-15T07:43:49Z

Resolves a merge issue with: drivers/tty/hvc/hvcs.c and we want the tty/serial fixes from 5.12-rc3 in here as well. Signed-off-by: Greg Kroah-Hartman

tty: localise ptychar and make it const

2021-03-10T08:34:09Z

ptychar was not const, so mark it as such. And move this variable to the only place where it's used. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210302062214.29627-36-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: let tty_unregister_driver return void

2021-03-10T08:34:09Z

Now that noone checks the return value, switch the return type of tty_unregister_driver to void. We can do that as we always return zero. Generally, drivers are not allowed to call tty_unregister_driver while there are open devices. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210302062214.29627-35-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

Revert "drivers:tty:pty: Fix a race causing data loss on close"

2021-03-10T08:27:56Z

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 Link: https://lore.kernel.org/r/00154592-c5ee-aaba-956e-b265473b53bc@linux.intel.com Cc: Corey Minyard Cc: Jiri Slaby Cc: Mark Brown , Fixes: 33d4ae988598 ("drivers:tty:pty: Fix a race causing data loss on close") Signed-off-by: Greg Kroah-Hartman