kernel/linux.git/drivers/usb/serial/generic.c, branch v4.19.77

USB: serial: fix unthrottle races

2019-05-16T17:41:18+00:00

commit 3f5edd58d040bfa4b74fb89bc02f0bc6b9cd06ab upstream. Fix two long-standing bugs which could potentially lead to memory corruption or leave the port throttled until it is reopened (on weakly ordered systems), respectively, when read-URB completion races with unthrottle(). First, the URB must not be marked as free before processing is complete to prevent it from being submitted by unthrottle() on another CPU. CPU 1 CPU 2 ================ ================ complete() unthrottle() process_urb(); smp_mb__before_atomic(); set_bit(i, free); if (test_and_clear_bit(i, free)) submit_urb(); Second, the URB must be marked as free before checking the throttled flag to prevent unthrottle() on another CPU from failing to observe that the URB needs to be submitted if complete() sees that the throttled flag is set. CPU 1 CPU 2 ================ ================ complete() unthrottle() set_bit(i, free); throttled = 0; smp_mb__after_atomic(); smp_mb(); if (throttled) if (test_and_clear_bit(i, free)) return; submit_urb(); Note that test_and_clear_bit() only implies barriers when the test is successful. To handle the case where the URB is still in use an explicit barrier needs to be added to unthrottle() for the second race condition. Fixes: d83b405383c9 ("USB: serial: add support for multiple read urbs") Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

USB: serial: Remove redundant license text

2017-11-04T10:55:38+00:00

Now that the SPDX tag is in all USB files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Signed-off-by: Greg Kroah-Hartman Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

USB: add SPDX identifiers to all remaining files in drivers/usb/

2017-11-04T10:48:02+00:00

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/usb/ and include/linux/usb* files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

USB: serial: relax generic driver bulk-endpoint requirement

2017-03-28T08:54:39+00:00

Relax the generic driver bulk-endpoint requirement. The driver handles devices without bulk-out endpoints just fine these days. Signed-off-by: Johan Hovold

USB: serial: add calc_num_ports callback to generic driver

2017-03-28T08:54:39+00:00

Add a calc_num_ports callback to the generic driver and verify that the device has the required endpoints there instead of in core. Note that the generic driver num_ports field was never used. Signed-off-by: Johan Hovold

USB: serial: add probe callback to generic driver

2017-03-28T08:54:39+00:00

Add a probe callback to the generic driver and print the only-for-testing message there. This is a first step in getting rid of the CONFIG_USB_SERIAL_GENERIC ifdef from usb-serial core. Signed-off-by: Johan Hovold

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32+00:00

Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

USB: serial: use variable for status

2016-07-16T10:45:39+00:00

This patch turns status in a variable read once from the URB. The long term plan is to deliver status to the callback. In addition it makes the code a bit more elegant. Signed-off-by: Oliver Neukum Signed-off-by: Johan Hovold

tty: Replace ASYNC_INITIALIZED bit and update atomically

2016-04-30T16:26:55+00:00

Replace ASYNC_INITIALIZED bit in the tty_port::flags field with TTY_PORT_INITIALIZED bit in the tty_port::iflags field. Introduce helpers tty_port_set_initialized() and tty_port_initialized() to abstract atomic bit ops. Note: the transforms for test_and_set_bit() and test_and_clear_bit() are unnecessary as the state transitions are already mutually exclusive; the tty lock prevents concurrent open/close/hangup. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

USB: serial: fix infinite wait_until_sent timeout

2015-03-07T02:44:14+00:00

Make sure to handle an infinite timeout (0). Note that wait_until_sent is currently never called with a 0-timeout argument due to a bug in tty_wait_until_sent. Fixes: dcf010503966 ("USB: serial: add generic wait_until_sent implementation") Cc: stable # v3.10 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman