diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/fault-injection/fault-injection.txt | 27 | ||||
| -rw-r--r-- | Documentation/fault-injection/notifier-error-inject.txt | 99 | ||||
| -rw-r--r-- | Documentation/printk-formats.txt | 15 | ||||
| -rw-r--r-- | Documentation/sysctl/fs.txt | 18 |
4 files changed, 153 insertions, 6 deletions
diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index ba4be8b7709..4cf1a2a6bd7 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -240,3 +240,30 @@ trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT echo "Injecting errors into the module $module... (interrupt to stop)" sleep 1000000 +Tool to run command with failslab or fail_page_alloc +---------------------------------------------------- +In order to make it easier to accomplish the tasks mentioned above, we can use +tools/testing/fault-injection/failcmd.sh. Please run a command +"./tools/testing/fault-injection/failcmd.sh --help" for more information and +see the following examples. + +Examples: + +Run a command "make -C tools/testing/selftests/ run_tests" with injecting slab +allocation failure. + + # ./tools/testing/fault-injection/failcmd.sh \ + -- make -C tools/testing/selftests/ run_tests + +Same as above except to specify 100 times failures at most instead of one time +at most by default. + + # ./tools/testing/fault-injection/failcmd.sh --times=100 \ + -- make -C tools/testing/selftests/ run_tests + +Same as above except to inject page allocation failure instead of slab +allocation failure. + + # env FAILCMD_TYPE=fail_page_alloc \ + ./tools/testing/fault-injection/failcmd.sh --times=100 \ + -- make -C tools/testing/selftests/ run_tests diff --git a/Documentation/fault-injection/notifier-error-inject.txt b/Documentation/fault-injection/notifier-error-inject.txt new file mode 100644 index 00000000000..c83526c364e --- /dev/null +++ b/Documentation/fault-injection/notifier-error-inject.txt @@ -0,0 +1,99 @@ +Notifier error injection +======================== + +Notifier error injection provides the ability to inject artifical errors to +specified notifier chain callbacks. It is useful to test the error handling of +notifier call chain failures which is rarely executed. There are kernel +modules that can be used to test the following notifiers. + + * CPU notifier + * PM notifier + * Memory hotplug notifier + * powerpc pSeries reconfig notifier + +CPU notifier error injection module +----------------------------------- +This feature can be used to test the error handling of the CPU notifiers by +injecting artifical errors to CPU notifier chain callbacks. + +If the notifier call chain should be failed with some events notified, write +the error code to debugfs interface +/sys/kernel/debug/notifier-error-inject/cpu/actions/<notifier event>/error + +Possible CPU notifier events to be failed are: + + * CPU_UP_PREPARE + * CPU_UP_PREPARE_FROZEN + * CPU_DOWN_PREPARE + * CPU_DOWN_PREPARE_FROZEN + +Example1: Inject CPU offline error (-1 == -EPERM) + + # cd /sys/kernel/debug/notifier-error-inject/cpu + # echo -1 > actions/CPU_DOWN_PREPARE/error + # echo 0 > /sys/devices/system/cpu/cpu1/online + bash: echo: write error: Operation not permitted + +Example2: inject CPU online error (-2 == -ENOENT) + + # echo -2 > actions/CPU_UP_PREPARE/error + # echo 1 > /sys/devices/system/cpu/cpu1/online + bash: echo: write error: No such file or directory + +PM notifier error injection module +---------------------------------- +This feature is controlled through debugfs interface +/sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error + +Possible PM notifier events to be failed are: + + * PM_HIBERNATION_PREPARE + * PM_SUSPEND_PREPARE + * PM_RESTORE_PREPARE + +Example: Inject PM suspend error (-12 = -ENOMEM) + + # cd /sys/kernel/debug/notifier-error-inject/pm/ + # echo -12 > actions/PM_SUSPEND_PREPARE/error + # echo mem > /sys/power/state + bash: echo: write error: Cannot allocate memory + +Memory hotplug notifier error injection module +---------------------------------------------- +This feature is controlled through debugfs interface +/sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error + +Possible memory notifier events to be failed are: + + * MEM_GOING_ONLINE + * MEM_GOING_OFFLINE + +Example: Inject memory hotplug offline error (-12 == -ENOMEM) + + # cd /sys/kernel/debug/notifier-error-inject/memory + # echo -12 > actions/MEM_GOING_OFFLINE/error + # echo offline > /sys/devices/system/memory/memoryXXX/state + bash: echo: write error: Cannot allocate memory + +powerpc pSeries reconfig notifier error injection module +-------------------------------------------------------- +This feature is controlled through debugfs interface +/sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error + +Possible pSeries reconfig notifier events to be failed are: + + * PSERIES_RECONFIG_ADD + * PSERIES_RECONFIG_REMOVE + * PSERIES_DRCONF_MEM_ADD + * PSERIES_DRCONF_MEM_REMOVE + +For more usage examples +----------------------- +There are tools/testing/selftests using the notifier error injection features +for CPU and memory notifiers. + + * tools/testing/selftests/cpu-hotplug/on-off-test.sh + * tools/testing/selftests/memory-hotplug/on-off-test.sh + +These scripts first do simple online and offline tests and then do fault +injection tests if notifier error injection module is available. diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt index 5df176ed59b..7561d7ed8e1 100644 --- a/Documentation/printk-formats.txt +++ b/Documentation/printk-formats.txt @@ -53,9 +53,20 @@ Struct Resources: For printing struct resources. The 'R' and 'r' specifiers result in a printed resource with ('R') or without ('r') a decoded flags member. +Raw buffer as a hex string: + %*ph 00 01 02 ... 3f + %*phC 00:01:02: ... :3f + %*phD 00-01-02- ... -3f + %*phN 000102 ... 3f + + For printing a small buffers (up to 64 bytes long) as a hex string with + certain separator. For the larger buffers consider to use + print_hex_dump(). + MAC/FDDI addresses: %pM 00:01:02:03:04:05 + %pMR 05:04:03:02:01:00 %pMF 00-01-02-03-04-05 %pm 000102030405 @@ -67,6 +78,10 @@ MAC/FDDI addresses: the 'M' specifier to use dash ('-') separators instead of the default separator. + For Bluetooth addresses the 'R' specifier shall be used after the 'M' + specifier to use reversed byte order suitable for visual interpretation + of Bluetooth addresses which are in the little endian order. + IPv4 addresses: %pI4 1.2.3.4 diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt index 13d6166d7a2..8c235b6e424 100644 --- a/Documentation/sysctl/fs.txt +++ b/Documentation/sysctl/fs.txt @@ -163,16 +163,22 @@ This value can be used to query and set the core dump mode for setuid or otherwise protected/tainted binaries. The modes are 0 - (default) - traditional behaviour. Any process which has changed - privilege levels or is execute only will not be dumped + privilege levels or is execute only will not be dumped. 1 - (debug) - all processes dump core when possible. The core dump is owned by the current user and no security is applied. This is intended for system debugging situations only. Ptrace is unchecked. + This is insecure as it allows regular users to examine the memory + contents of privileged processes. 2 - (suidsafe) - any binary which normally would not be dumped is dumped - readable by root only. This allows the end user to remove - such a dump but not access it directly. For security reasons - core dumps in this mode will not overwrite one another or - other files. This mode is appropriate when administrators are - attempting to debug problems in a normal environment. + anyway, but only if the "core_pattern" kernel sysctl is set to + either a pipe handler or a fully qualified path. (For more details + on this limitation, see CVE-2006-2451.) This mode is appropriate + when administrators are attempting to debug problems in a normal + environment, and either have a core dump pipe handler that knows + to treat privileged core dumps with care, or specific directory + defined for catching core dumps. If a core dump happens without + a pipe handler or fully qualifid path, a message will be emitted + to syslog warning about the lack of a correct setting. ============================================================== |