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  1. 25 4月, 2014 4 次提交
    • D
      serial: samsung: Use the passed in "port", fixing kgdb w/ no console · bb7f09ba
      由 Doug Anderson 提交于 
      The two functions in the samsung serial driver used for writing
characters out to the port were inconsistent about whether they used
the passed in "port" or the global "cons_uart".  There was no reason
to use the global and the use of the global in
s3c24xx_serial_put_poll_char() caused a crash in the case where you
used the serial port for kgdboc but not for console.

Fix it so we used the passed in variable.

Note that this doesn't fix all problems with the samsung serial
driver.  Specifically:
* s3c24xx_serial_console_putchar() is still 99% identical to
  s3c24xx_serial_put_poll_char() (the function signature is different,
  but that's about it).  A future patch will make them slightly less
  identical and judging by other serial drivers we may need yet more
  differences eventually.
* The samsung serial driver still doesn't allow you to have more than
  one console port since it still uses the global cons_uart in
  s3c24xx_serial_console_write().
Signed-off-by: NDoug Anderson <dianders@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bb7f09ba
    • L
      serial: 8250: Fix thread unsafe __dma_tx_complete function · f8fd1b03
      由 Loic Poulain 提交于 
      __dma_tx_complete is not protected against concurrent
call of serial8250_tx_dma. it can lead to circular tail
index corruption or parallel call of serial_tx_dma on the
same data portion.

This patch fixes this issue by holding the port lock.
Signed-off-by: NLoic Poulain <loic.poulain@intel.com>
Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f8fd1b03
    • L
      8250_core: Fix unwanted TX chars write · b08c9c31
      由 Loic Poulain 提交于 
      On transmit-hold-register empty, serial8250_tx_chars
should be called only if we don't use DMA.
DMA has its own tx cycle.
Signed-off-by: NLoic Poulain <loic.poulain@intel.com>
Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b08c9c31
    • M
      tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc · 6a20dbd6
      由 Manfred Schlaegl 提交于 
      The race was introduced while development of linux-3.11 by
e8437d7e and
e9975fde.
Originally it was found and reproduced on linux-3.12.15 and
linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the
target uart in a loop with 100 milliseconds delay.

In short:
 1. The consumer flush_to_ldisc is on to remove the head tty_buffer.
 2. The producer adds a number of bytes, so that a new tty_buffer must
	be allocated and added by __tty_buffer_request_room.
 3. The consumer removes the head tty_buffer element, without handling
	newly committed data.

Detailed example:
 * Initial buffer:
   * Head, Tail -> 0: used=250; commit=250; read=240; next=NULL
 * Consumer: ''flush_to_ldisc''
   * consumed 10 Byte
   * buffer:
     * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
{{{
		count = head->commit - head->read;	// count = 0
		if (!count) {				// enter
			// INTERRUPTED BY PRODUCER ->
			if (head->next == NULL)
				break;
			buf->head = head->next;
			tty_buffer_free(port, head);
			continue;
		}
}}}
 * Producer: tty_insert_flip_... 10 bytes + tty_flip_buffer_push
   * buffer:
     * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
   * added 6 bytes: head-element filled to maximum.
     * buffer:
       * Head, Tail -> 0: used=256; commit=250; read=250; next=NULL
   * added 4 bytes: __tty_buffer_request_room is called
     * buffer:
       * Head -> 0: used=256; commit=256; read=250; next=1
       * Tail -> 1: used=4; commit=0; read=250 next=NULL
   * push (tty_flip_buffer_push)
     * buffer:
       * Head -> 0: used=256; commit=256; read=250; next=1
       * Tail -> 1: used=4; commit=4; read=250 next=NULL
 * Consumer
{{{
		count = head->commit - head->read;
		if (!count) {
			// INTERRUPTED BY PRODUCER <-
			if (head->next == NULL)		// -> no break
				break;
			buf->head = head->next;
			tty_buffer_free(port, head);
			// ERROR: tty_buffer head freed -> 6 bytes lost
			continue;
		}
}}}

This patch reintroduces a spin_lock to protect this case. Perhaps later
a lock-less solution could be found.
Signed-off-by: NManfred Schlaegl <manfred.schlaegl@gmx.at>
Cc: stable <stable@vger.kernel.org> # 3.11
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6a20dbd6
  3. 18 4月, 2014 1 次提交
  5. 17 4月, 2014 12 次提交
  7. 07 4月, 2014 1 次提交
  9. 20 3月, 2014 1 次提交
  11. 19 3月, 2014 1 次提交
  13. 18 3月, 2014 15 次提交
  15. 09 3月, 2014 3 次提交
  17. 07 3月, 2014 1 次提交
  19. 01 3月, 2014 1 次提交