linux-stable.git/drivers/tty, branch v5.3.8

serial: uartps: Fix uartps_major handling

2019-10-17T20:46:44+00:00

commit 5e9bd2d70ae7c00a95a22994abf1eef728649e64 upstream.

There are two parts which should be fixed. The first one is to assigned
uartps_major at the end of probe() to avoid complicated logic when
something fails.
The second part is initialized uartps_major number to 0 when last device is
removed. This will ensure that on next probe driver will ask for new
dynamic major number.

Fixes: ab262666018d ("serial: uartps: Use the same dynamic major number for all ports")
Reported-by: Paul Thomas 
Cc: stable 
Signed-off-by: Michal Simek 
Link: https://lore.kernel.org/r/d2652cda992833315c4f96f06953eb547f928918.1570194248.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman

serial: uartlite: fix exit path null pointer

2019-10-17T20:46:43+00:00

commit a553add0846f355a28ed4e81134012e4a1e280c2 upstream.

Call uart_unregister_driver() conditionally instead of
unconditionally, only if it has been previously registered.

This uses driver.state, just as the sh-sci.c driver does.

Fixes this null pointer dereference in tty_unregister_driver(),
since the 'driver' argument is null:

  general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
  RIP: 0010:tty_unregister_driver+0x25/0x1d0

Fixes: 238b8721a554 ("[PATCH] serial uartlite driver")
Signed-off-by: Randy Dunlap 
Cc: stable 
Cc: Peter Korsgaard 
Link: https://lore.kernel.org/r/9c8e6581-6fcc-a595-0897-4d90f5d710df@infradead.org
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: reschedule TX after RX was started

2019-09-21T05:19:43+00:00

commit d2ace81bf902a9f11d52e59e5d232d2255a0e353 upstream.

When half-duplex RS485 communication is used, after RX is started, TX
tasklet still needs to be  scheduled tasklet. This avoids console freezing
when more data is to be transmitted, if the serial communication is not
closed.

Fixes: 69646d7a3689 ("tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped")
Signed-off-by: Razvan Stefanescu 
Cc: stable 
Link: https://lore.kernel.org/r/20190813074025.16218-1-razvan.stefanescu@microchip.com
Signed-off-by: Greg Kroah-Hartman

serial: sprd: correct the wrong sequence of arguments

2019-09-21T05:19:43+00:00

commit 9c801e313195addaf11c16e155f50789d6ebfd19 upstream.

The sequence of arguments which was passed to handle_lsr_errors() didn't
match the parameters defined in that function, &lsr was passed to flag
and &flag was passed to lsr, this patch fixed that.

Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support")
Signed-off-by: Chunyan Zhang 
Signed-off-by: Chunyan Zhang 
Cc: stable 
Link: https://lore.kernel.org/r/20190905074151.5268-1-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman

kgdboc: disable the console lock when in kgdb

2019-07-30T15:39:39+00:00

After commit ddde3c18b700 ("vt: More locking checks") kdb / kgdb has
become useless because my console is filled with spews of:

WARNING: CPU: 0 PID: 0 at .../drivers/tty/vt/vt.c:3846 con_is_visible+0x50/0x74
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1+ #48
Hardware name: Rockchip (Device Tree)
Backtrace:
[] (dump_backtrace) from [] (show_stack+0x20/0x24)
[] (show_stack) from [] (dump_stack+0xb0/0xd0)
[] (dump_stack) from [] (__warn+0xec/0x11c)
[] (__warn) from [] (warn_slowpath_null+0x4c/0x58)
[] (warn_slowpath_null) from [] (con_is_visible+0x50/0x74)
[] (con_is_visible) from [] (con_scroll+0x108/0x1ac)
[] (con_scroll) from [] (lf+0x44/0x88)
[] (lf) from [] (vt_console_print+0x1a4/0x2bc)
[] (vt_console_print) from [] (vkdb_printf+0x420/0x8a4)
[] (vkdb_printf) from [] (kdb_printf+0x44/0x60)
[] (kdb_printf) from [] (kdb_main_loop+0xf4/0x6e0)
[] (kdb_main_loop) from [] (kdb_stub+0x268/0x398)
[] (kdb_stub) from [] (kgdb_cpu_enter+0x1f8/0x674)
[] (kgdb_cpu_enter) from [] (kgdb_handle_exception+0x1c4/0x1fc)
[] (kgdb_handle_exception) from [] (kgdb_compiled_brk_fn+0x30/0x3c)
[] (kgdb_compiled_brk_fn) from [] (do_undefinstr+0x180/0x1a0)
[] (do_undefinstr) from [] (__und_svc_finish+0x0/0x3c)
...
[] (kgdb_breakpoint) from [] (sysrq_handle_dbg+0x58/0x6c)
[] (sysrq_handle_dbg) from [] (__handle_sysrq+0xac/0x154)

Let's disable this warning when we're in kgdb to avoid the spew.  The
whole system is stopped when we're in kgdb so we can't exactly wait
for someone else to drop the lock.  Presumably the best we can do is
to disable the warning and hope for the best.

Fixes: ddde3c18b700 ("vt: More locking checks")
Cc: Daniel Vetter 
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20190725183551.169208-1-dianders@chromium.org
Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2019-07-28T17:18:33+00:00

Pull tty fixes from Greg KH:
 "Here are two tty/vt fixes:

   - delete the netx-serial driver as the arch has been removed, no need
     to keep the serial driver for it around either.

   - vt console_lock fix to resolve a reported noisy warning at runtime

  Both of these have been in linux-next with no reported issues"

* tag 'tty-5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  vt: Grab console_lock around con_is_bound in show_bind
  tty: serial: netx: Delete driver

Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-07-28T04:10:26+00:00

Pull locking fixes from Thomas Gleixner:
 "A set of locking fixes:

   - Address the fallout of the rwsem rework. Missing ACQUIREs and a
     sanity check to prevent a use-after-free

   - Add missing checks for unitialized mutexes when mutex debugging is
     enabled.

   - Remove the bogus code in the generic SMP variant of
     arch_futex_atomic_op_inuser()

   - Fixup the #ifdeffery in lockdep to prevent compile warnings"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/mutex: Test for initialized mutex
  locking/lockdep: Clean up #ifdef checks
  locking/lockdep: Hide unused 'class' variable
  locking/rwsem: Add ACQUIRE comments
  tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop
  lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop
  locking/rwsem: Add missing ACQUIRE to read_slowpath exit when queue is empty
  locking/rwsem: Don't call owner_on_cpu() on read-owner
  futex: Cleanup generic SMP variant of arch_futex_atomic_op_inuser()

tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop

2019-07-25T13:39:24+00:00

While reviewing rwsem down_slowpath, Will noticed ldsem had a copy of
a bug we just found for rwsem.

  X = 0;

  CPU0			CPU1

  rwsem_down_read()
    for (;;) {
      set_current_state(TASK_UNINTERRUPTIBLE);

                        X = 1;
                        rwsem_up_write();
                          rwsem_mark_wake()
                            atomic_long_add(adjustment, &sem->count);
                            smp_store_release(&waiter->task, NULL);

      if (!waiter.task)
        break;

      ...
    }

  r = X;

Allows 'r == 0'.

Reported-by: Will Deacon 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Will Deacon 
Cc: Linus Torvalds 
Cc: Peter Hurley 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 4898e640caf0 ("tty: Add timed, writer-prioritized rw semaphore")
Signed-off-by: Ingo Molnar

vt: Grab console_lock around con_is_bound in show_bind

2019-07-25T11:47:35+00:00

Not really harmful not to, but also not harm in grabbing the lock. And
this shuts up a new WARNING I introduced in commit ddde3c18b700 ("vt:
More locking checks").

Reported-by: Jens Remus 
Cc: linux-kernel@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: Nicolas Pitre 
Cc: Martin Hostettler 
Cc: Adam Borowski 
Cc: Mikulas Patocka 
Cc: Daniel Vetter 
Cc: Sam Ravnborg 
Fixes: ddde3c18b700 ("vt: More locking checks")
Signed-off-by: Daniel Vetter 
Tested-by: Jens Remus 
Acked-by: Sam Ravnborg 
Link: https://lore.kernel.org/r/20190718080903.22622-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman

tty: serial: netx: Delete driver

2019-07-25T10:05:28+00:00

The Netx ARM machine was deleted from the kernel. This driver
had no users and has to go.

Cc: Robert Schwebel 
Cc: Sascha Hauer 
Signed-off-by: Linus Walleij 
Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20190722065146.4844-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman