|
|
@@ -17,7 +17,7 @@ o fail_page_alloc
|
|
|
|
|
|
o fail_make_request
|
|
|
|
|
|
- injects disk IO errors on permitted devices by
|
|
|
+ injects disk IO errors on devices permitted by setting
|
|
|
/sys/block/<device>/make-it-fail or
|
|
|
/sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
|
|
|
|
|
|
@@ -29,16 +29,16 @@ o debugfs entries
|
|
|
fault-inject-debugfs kernel module provides some debugfs entries for runtime
|
|
|
configuration of fault-injection capabilities.
|
|
|
|
|
|
-- /debug/*/probability:
|
|
|
+- /debug/fail*/probability:
|
|
|
|
|
|
likelihood of failure injection, in percent.
|
|
|
Format: <percent>
|
|
|
|
|
|
- Note that one-failure-per-handred is a very high error rate
|
|
|
- for some testcases. Please set probably=100 and configure
|
|
|
- /debug/*/interval for such testcases.
|
|
|
+ Note that one-failure-per-hundred is a very high error rate
|
|
|
+ for some testcases. Consider setting probability=100 and configure
|
|
|
+ /debug/fail*/interval for such testcases.
|
|
|
|
|
|
-- /debug/*/interval:
|
|
|
+- /debug/fail*/interval:
|
|
|
|
|
|
specifies the interval between failures, for calls to
|
|
|
should_fail() that pass all the other tests.
|
|
|
@@ -46,37 +46,36 @@ configuration of fault-injection capabilities.
|
|
|
Note that if you enable this, by setting interval>1, you will
|
|
|
probably want to set probability=100.
|
|
|
|
|
|
-- /debug/*/times:
|
|
|
+- /debug/fail*/times:
|
|
|
|
|
|
specifies how many times failures may happen at most.
|
|
|
A value of -1 means "no limit".
|
|
|
|
|
|
-- /debug/*/space:
|
|
|
+- /debug/fail*/space:
|
|
|
|
|
|
specifies an initial resource "budget", decremented by "size"
|
|
|
on each call to should_fail(,size). Failure injection is
|
|
|
suppressed until "space" reaches zero.
|
|
|
|
|
|
-- /debug/*/verbose
|
|
|
+- /debug/fail*/verbose
|
|
|
|
|
|
Format: { 0 | 1 | 2 }
|
|
|
- specifies the verbosity of the messages when failure is injected.
|
|
|
- We default to 0 (no extra messages), setting it to '1' will
|
|
|
- print only to tell failure happened, '2' will print call trace too -
|
|
|
- it is useful to debug the problems revealed by fault injection
|
|
|
- capabilities.
|
|
|
+ specifies the verbosity of the messages when failure is
|
|
|
+ injected. '0' means no messages; '1' will print only a single
|
|
|
+ log line per failure; '2' will print a call trace too -- useful
|
|
|
+ to debug the problems revealed by fault injection.
|
|
|
|
|
|
-- /debug/*/task-filter:
|
|
|
+- /debug/fail*/task-filter:
|
|
|
|
|
|
- Format: { 0 | 1 }
|
|
|
- A value of '0' disables filtering by process (default).
|
|
|
+ Format: { 'Y' | 'N' }
|
|
|
+ A value of 'N' disables filtering by process (default).
|
|
|
Any positive value limits failures to only processes indicated by
|
|
|
/proc/<pid>/make-it-fail==1.
|
|
|
|
|
|
-- /debug/*/require-start:
|
|
|
-- /debug/*/require-end:
|
|
|
-- /debug/*/reject-start:
|
|
|
-- /debug/*/reject-end:
|
|
|
+- /debug/fail*/require-start:
|
|
|
+- /debug/fail*/require-end:
|
|
|
+- /debug/fail*/reject-start:
|
|
|
+- /debug/fail*/reject-end:
|
|
|
|
|
|
specifies the range of virtual addresses tested during
|
|
|
stacktrace walking. Failure is injected only if some caller
|
|
|
@@ -85,22 +84,23 @@ configuration of fault-injection capabilities.
|
|
|
Default required range is [0,ULONG_MAX) (whole of virtual address space).
|
|
|
Default rejected range is [0,0).
|
|
|
|
|
|
-- /debug/*/stacktrace-depth:
|
|
|
+- /debug/fail*/stacktrace-depth:
|
|
|
|
|
|
specifies the maximum stacktrace depth walked during search
|
|
|
- for a caller within [address-start,address-end).
|
|
|
+ for a caller within [require-start,require-end) OR
|
|
|
+ [reject-start,reject-end).
|
|
|
|
|
|
- /debug/fail_page_alloc/ignore-gfp-highmem:
|
|
|
|
|
|
- Format: { 0 | 1 }
|
|
|
- default is 0, setting it to '1' won't inject failures into
|
|
|
+ Format: { 'Y' | 'N' }
|
|
|
+ default is 'N', setting it to 'Y' won't inject failures into
|
|
|
highmem/user allocations.
|
|
|
|
|
|
- /debug/failslab/ignore-gfp-wait:
|
|
|
- /debug/fail_page_alloc/ignore-gfp-wait:
|
|
|
|
|
|
- Format: { 0 | 1 }
|
|
|
- default is 0, setting it to '1' will inject failures
|
|
|
+ Format: { 'Y' | 'N' }
|
|
|
+ default is 'N', setting it to 'Y' will inject failures
|
|
|
only into non-sleep allocations (GFP_ATOMIC allocations).
|
|
|
|
|
|
o Boot option
|
|
|
@@ -124,22 +124,22 @@ o define the fault attributes
|
|
|
Please see the definition of struct fault_attr in fault-inject.h
|
|
|
for details.
|
|
|
|
|
|
-o provide the way to configure fault attributes
|
|
|
+o provide a way to configure fault attributes
|
|
|
|
|
|
- boot option
|
|
|
|
|
|
If you need to enable the fault injection capability from boot time, you can
|
|
|
- provide boot option to configure it. There is a helper function for it.
|
|
|
+ provide boot option to configure it. There is a helper function for it:
|
|
|
|
|
|
- setup_fault_attr(attr, str);
|
|
|
+ setup_fault_attr(attr, str);
|
|
|
|
|
|
- debugfs entries
|
|
|
|
|
|
failslab, fail_page_alloc, and fail_make_request use this way.
|
|
|
- There is a helper function for it.
|
|
|
+ Helper functions:
|
|
|
|
|
|
- init_fault_attr_entries(entries, attr, name);
|
|
|
- void cleanup_fault_attr_entries(entries);
|
|
|
+ init_fault_attr_entries(entries, attr, name);
|
|
|
+ void cleanup_fault_attr_entries(entries);
|
|
|
|
|
|
- module parameters
|
|
|
|
|
|
@@ -149,9 +149,9 @@ o provide the way to configure fault attributes
|
|
|
|
|
|
o add a hook to insert failures
|
|
|
|
|
|
- should_fail() returns 1 when failures should happen.
|
|
|
+ Upon should_fail() returning true, client code should inject a failure.
|
|
|
|
|
|
- should_fail(attr,size);
|
|
|
+ should_fail(attr, size);
|
|
|
|
|
|
Application Examples
|
|
|
--------------------
|
Don Mullis