[PATCH] fault-injection: Correct, disambiguate, and reformat documentation
Correct, disambiguate, and reformat documentation. Signed-off-by: Don Mullis <dwm@meer.net> Cc: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>hifive-unleashed-5.1
Don Mullis
Linus Torvalds
parent
83ba254688
commit
5d0ffa2b84
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@ -26,6 +26,6 @@ fi
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# Disable any fault injection
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echo 0 > /debug/$1/stacktrace-depth
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echo `cat /sys/module/$2/sections/.text` > /debug/$1/address-start
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echo `cat /sys/module/$2/sections/.exit.text` > /debug/$1/address-end
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echo `cat /sys/module/$2/sections/.text` > /debug/$1/require-start
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echo `cat /sys/module/$2/sections/.exit.text` > /debug/$1/require-end
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echo $STACKTRACE_DEPTH > /debug/$1/stacktrace-depth
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@ -17,7 +17,7 @@ o fail_page_alloc
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o fail_make_request
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injects disk IO errors on permitted devices by
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injects disk IO errors on devices permitted by setting
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/sys/block/<device>/make-it-fail or
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/sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
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@ -29,16 +29,16 @@ o debugfs entries
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fault-inject-debugfs kernel module provides some debugfs entries for runtime
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configuration of fault-injection capabilities.
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- /debug/*/probability:
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- /debug/fail*/probability:
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likelihood of failure injection, in percent.
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Format: <percent>
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Note that one-failure-per-handred is a very high error rate
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for some testcases. Please set probably=100 and configure
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/debug/*/interval for such testcases.
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Note that one-failure-per-hundred is a very high error rate
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for some testcases. Consider setting probability=100 and configure
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/debug/fail*/interval for such testcases.
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- /debug/*/interval:
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- /debug/fail*/interval:
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specifies the interval between failures, for calls to
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should_fail() that pass all the other tests.
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@ -46,37 +46,36 @@ configuration of fault-injection capabilities.
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Note that if you enable this, by setting interval>1, you will
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probably want to set probability=100.
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- /debug/*/times:
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- /debug/fail*/times:
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specifies how many times failures may happen at most.
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A value of -1 means "no limit".
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- /debug/*/space:
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- /debug/fail*/space:
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specifies an initial resource "budget", decremented by "size"
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on each call to should_fail(,size). Failure injection is
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suppressed until "space" reaches zero.
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- /debug/*/verbose
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- /debug/fail*/verbose
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Format: { 0 | 1 | 2 }
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specifies the verbosity of the messages when failure is injected.
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We default to 0 (no extra messages), setting it to '1' will
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print only to tell failure happened, '2' will print call trace too -
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it is useful to debug the problems revealed by fault injection
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capabilities.
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specifies the verbosity of the messages when failure is
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injected. '0' means no messages; '1' will print only a single
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log line per failure; '2' will print a call trace too -- useful
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to debug the problems revealed by fault injection.
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- /debug/*/task-filter:
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- /debug/fail*/task-filter:
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Format: { 0 | 1 }
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A value of '0' disables filtering by process (default).
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Format: { 'Y' | 'N' }
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A value of 'N' disables filtering by process (default).
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Any positive value limits failures to only processes indicated by
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/proc/<pid>/make-it-fail==1.
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- /debug/*/require-start:
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- /debug/*/require-end:
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- /debug/*/reject-start:
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- /debug/*/reject-end:
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- /debug/fail*/require-start:
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- /debug/fail*/require-end:
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- /debug/fail*/reject-start:
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- /debug/fail*/reject-end:
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specifies the range of virtual addresses tested during
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stacktrace walking. Failure is injected only if some caller
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@ -85,22 +84,23 @@ configuration of fault-injection capabilities.
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Default required range is [0,ULONG_MAX) (whole of virtual address space).
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Default rejected range is [0,0).
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- /debug/*/stacktrace-depth:
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- /debug/fail*/stacktrace-depth:
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specifies the maximum stacktrace depth walked during search
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for a caller within [address-start,address-end).
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for a caller within [require-start,require-end) OR
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[reject-start,reject-end).
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- /debug/fail_page_alloc/ignore-gfp-highmem:
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Format: { 0 | 1 }
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default is 0, setting it to '1' won't inject failures into
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Format: { 'Y' | 'N' }
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default is 'N', setting it to 'Y' won't inject failures into
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highmem/user allocations.
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- /debug/failslab/ignore-gfp-wait:
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- /debug/fail_page_alloc/ignore-gfp-wait:
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Format: { 0 | 1 }
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default is 0, setting it to '1' will inject failures
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Format: { 'Y' | 'N' }
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default is 'N', setting it to 'Y' will inject failures
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only into non-sleep allocations (GFP_ATOMIC allocations).
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o Boot option
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@ -124,22 +124,22 @@ o define the fault attributes
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Please see the definition of struct fault_attr in fault-inject.h
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for details.
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o provide the way to configure fault attributes
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o provide a way to configure fault attributes
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- boot option
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If you need to enable the fault injection capability from boot time, you can
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provide boot option to configure it. There is a helper function for it.
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provide boot option to configure it. There is a helper function for it:
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setup_fault_attr(attr, str);
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setup_fault_attr(attr, str);
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- debugfs entries
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failslab, fail_page_alloc, and fail_make_request use this way.
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There is a helper function for it.
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Helper functions:
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init_fault_attr_entries(entries, attr, name);
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void cleanup_fault_attr_entries(entries);
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init_fault_attr_entries(entries, attr, name);
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void cleanup_fault_attr_entries(entries);
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- module parameters
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@ -149,9 +149,9 @@ o provide the way to configure fault attributes
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o add a hook to insert failures
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should_fail() returns 1 when failures should happen.
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Upon should_fail() returning true, client code should inject a failure.
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should_fail(attr,size);
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should_fail(attr, size);
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Application Examples
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--------------------
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