+ vt-incomplete-initialization-of-vc_tab_stop.patch added to -mm tree

+ vt-incomplete-initialization-of-vc_tab_stop.patch added to -mm tree

[akpm]

The patch titled
     vt: incomplete initialization of vc_tab_stop
has been added to the -mm tree.  Its filename is
     vt-incomplete-initialization-of-vc_tab_stop.patch

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out what to do about this

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------------------------------------------------------
Subject: vt: incomplete initialization of vc_tab_stop
From: Wolfgang Kroworsch <wolfgang@kroworsch.de>

Problem 1 (see patch below):
  vc_tab_stop is declared as an array of 8 unsigned ints in struct
  vc_data in include/linux/console_struct.h .
  In drivers/char/vt.c only 5 of these 8 unsigned ints get initialized
  leading to unintended tabulator placement on displays with more than
  160 columns text.

Problem 2 (open):
  Upcoming displays will have more than 256 columns of text leading to
  invalid memory access in drivers/char/vt.c during tabulator
  calculations:
    if (vc->vc_tab_stop[vc->vc_x >> 5] & (1 << (vc->vc_x & 31)))
	break;

Signed-off-by: Wolfgang Kroworsch <wolfgang@kroworsch.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/char/vt.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff -puN drivers/char/vt.c~vt-incomplete-initialization-of-vc_tab_stop drivers/char/vt.c
--- a/drivers/char/vt.c~vt-incomplete-initialization-of-vc_tab_stop
+++ a/drivers/char/vt.c
@@ -1642,7 +1642,10 @@ static void reset_terminal(struct vc_dat
 	vc->vc_tab_stop[1]	=
 	vc->vc_tab_stop[2]	=
 	vc->vc_tab_stop[3]	=
-	vc->vc_tab_stop[4]	= 0x01010101;
+	vc->vc_tab_stop[4]	=
+	vc->vc_tab_stop[5]	=
+	vc->vc_tab_stop[6]	=
+	vc->vc_tab_stop[7]	= 0x01010101;
 
 	vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
 	vc->vc_bell_duration = DEFAULT_BELL_DURATION;
@@ -1933,7 +1936,10 @@ static void do_con_trol(struct tty_struc
 					vc->vc_tab_stop[1] =
 					vc->vc_tab_stop[2] =
 					vc->vc_tab_stop[3] =
-					vc->vc_tab_stop[4] = 0;
+					vc->vc_tab_stop[4] =
+					vc->vc_tab_stop[5] =
+					vc->vc_tab_stop[6] =
+					vc->vc_tab_stop[7] = 0;
 			}
 			return;
 		case 'm':
_

Patches currently in -mm which might be from wolfgang@kroworsch.de are

vt-incomplete-initialization-of-vc_tab_stop.patch
vt-incomplete-initialization-of-vc_tab_stop-fix.patch