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| author | James Morris <jmorris@namei.org> | 2009-06-11 11:03:14 +1000 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2009-06-11 11:03:14 +1000 |
| commit | 73fbad283cfbbcf02939bdbda31fc4a30e729cca (patch) | |
| tree | 7c89fe13e1b4a2c7f2d60f4ea6eaf69c14bccab7 /mm/Kconfig | |
| parent | 769f3e8c384795cc350e2aae27de2a12374d19d4 (diff) | |
| parent | 35f2c2f6f6ae13ef23c4f68e6d3073753077ca43 (diff) | |
| download | linux-3.10-73fbad283cfbbcf02939bdbda31fc4a30e729cca.tar.gz linux-3.10-73fbad283cfbbcf02939bdbda31fc4a30e729cca.tar.bz2 linux-3.10-73fbad283cfbbcf02939bdbda31fc4a30e729cca.zip | |
Merge branch 'next' into for-linus
Diffstat (limited to 'mm/Kconfig')
| -rw-r--r-- | mm/Kconfig | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index c2b57d81e15..71830ba7b98 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -226,6 +226,25 @@ config HAVE_MLOCKED_PAGE_BIT config MMU_NOTIFIER bool +config DEFAULT_MMAP_MIN_ADDR + int "Low address space to protect from user allocation" + default 4096 + help + This is the portion of low virtual memory which should be protected + from userspace allocation. Keeping a user from writing to low pages + can help reduce the impact of kernel NULL pointer bugs. + + For most ia64, ppc64 and x86 users with lots of address space + a value of 65536 is reasonable and should cause no problems. + On arm and other archs it should not be higher than 32768. + Programs which use vm86 functionality would either need additional + permissions from either the LSM or the capabilities module or have + this protection disabled. + + This value can be changed after boot using the + /proc/sys/vm/mmap_min_addr tunable. + + config NOMMU_INITIAL_TRIM_EXCESS int "Turn on mmap() excess space trimming before booting" depends on !MMU |