diff options
Diffstat (limited to 'Documentation/sysctl/kernel.txt')
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 46 |
1 files changed, 33 insertions, 13 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 322a00bb99d..3e5b63ebb82 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -19,6 +19,7 @@ Currently, these files might (depending on your configuration) show up in /proc/sys/kernel: - acpi_video_flags - acct +- callhome [ S390 only ] - auto_msgmni - core_pattern - core_uses_pid @@ -91,6 +92,21 @@ valid for 30 seconds. ============================================================== +callhome: + +Controls the kernel's callhome behavior in case of a kernel panic. + +The s390 hardware allows an operating system to send a notification +to a service organization (callhome) in case of an operating system panic. + +When the value in this file is 0 (which is the default behavior) +nothing happens in case of a kernel panic. If this value is set to "1" +the complete kernel oops message is send to the IBM customer service +organization in case the mainframe the Linux operating system is running +on has a service contract with IBM. + +============================================================== + core_pattern: core_pattern is used to specify a core dumpfile pattern name. @@ -303,25 +319,29 @@ This option can be used to select the type of process address space randomization that is used in the system, for architectures that support this feature. -0 - Turn the process address space randomization off by default. +0 - Turn the process address space randomization off. This is the + default for architectures that do not support this feature anyways, + and kernels that are booted with the "norandmaps" parameter. 1 - Make the addresses of mmap base, stack and VDSO page randomized. This, among other things, implies that shared libraries will be - loaded to random addresses. Also for PIE-linked binaries, the location - of code start is randomized. + loaded to random addresses. Also for PIE-linked binaries, the + location of code start is randomized. This is the default if the + CONFIG_COMPAT_BRK option is enabled. - With heap randomization, the situation is a little bit more - complicated. - There a few legacy applications out there (such as some ancient +2 - Additionally enable heap randomization. This is the default if + CONFIG_COMPAT_BRK is disabled. + + There are a few legacy applications out there (such as some ancient versions of libc.so.5 from 1996) that assume that brk area starts - just after the end of the code+bss. These applications break when - start of the brk area is randomized. There are however no known + just after the end of the code+bss. These applications break when + start of the brk area is randomized. There are however no known non-legacy applications that would be broken this way, so for most - systems it is safe to choose full randomization. However there is - a CONFIG_COMPAT_BRK option for systems with ancient and/or broken - binaries, that makes heap non-randomized, but keeps all other - parts of process address space randomized if randomize_va_space - sysctl is turned on. + systems it is safe to choose full randomization. + + Systems with ancient and/or broken binaries should be configured + with CONFIG_COMPAT_BRK enabled, which excludes the heap from process + address space randomization. ============================================================== |