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Commit 9af0c7a6fa860698d080481f24a342ba74b68982

Authored by Ludwig Nussel
Committed by Ingo Molnar
1 parent 1762391530
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

x86: Fix mmap random address range 

On x86_32 casting the unsigned int result of get_random_int() to
long may result in a negative value.  On x86_32 the range of
mmap_rnd() therefore was -255 to 255.  The 32bit mode on x86_64
used 0 to 255 as intended.

The bug was introduced by 675a081 ("x86: unify mmap_{32|64}.c")
in January 2008.

Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: harvey.harrison@gmail.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/201111152246.pAFMklOB028527@wpaz5.hot.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff

... ... @@ -75,9 +75,9 @@
75 75 */
76 76 if (current->flags & PF_RANDOMIZE) {
77 77 if (mmap_is_ia32())
78   - rnd = (long)get_random_int() % (1<<8);
  78 + rnd = get_random_int() % (1<<8);
79 79 else
80   - rnd = (long)(get_random_int() % (1<<28));
  80 + rnd = get_random_int() % (1<<28);
81 81 }
82 82 return rnd << PAGE_SHIFT;
83 83 }