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Commit fdde5f3b authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'error-injection' 

Masami Hiramatsu says:

====================
Here are the 5th version of patches to moving error injection
table from kprobes. This version fixes a bug and update
fail-function to support multiple function error injection.

Here is the previous version:

https://patchwork.ozlabs.org/cover/858663/



Changes in v5:
 - [3/5] Fix a bug that within_error_injection returns false always.
 - [5/5] Update to support multiple function error injection.

Thank you,
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents daaf24c6 4b1a29a7

Documentation/fault-injection/fault-injection.txt

+68 −0
Original line number Diff line number Diff line
@@ -30,6 +30,12 @@ o fail_mmc_request 
  injects MMC data errors on devices permitted by setting

  debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request



o fail_function



  injects error return on specific functions, which are marked by

  ALLOW_ERROR_INJECTION() macro, by setting debugfs entries

  under /sys/kernel/debug/fail_function. No boot option supported.



Configure fault-injection capabilities behavior

-----------------------------------------------
@@ -123,6 +129,29 @@ configuration of fault-injection capabilities. 
	default is 'N', setting it to 'Y' will disable failure injections

	when dealing with private (address space) futexes.



- /sys/kernel/debug/fail_function/inject:



	Format: { 'function-name' | '!function-name' | '' }

	specifies the target function of error injection by name.

	If the function name leads '!' prefix, given function is

	removed from injection list. If nothing specified ('')

	injection list is cleared.



- /sys/kernel/debug/fail_function/injectable:



	(read only) shows error injectable functions and what type of

	error values can be specified. The error type will be one of

	below;

	- NULL:	retval must be 0.

	- ERRNO: retval must be -1 to -MAX_ERRNO (-4096).

	- ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096).



- /sys/kernel/debug/fail_function/<functiuon-name>/retval:



	specifies the "error" return value to inject to the given

	function for given function. This will be created when

	user specifies new injection entry.



o Boot option



In order to inject faults while debugfs is not available (early boot time),
@@ -268,6 +297,45 @@ trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT 
echo "Injecting errors into the module $module... (interrupt to stop)"

sleep 1000000



------------------------------------------------------------------------------



o Inject open_ctree error while btrfs mount



#!/bin/bash



rm -f testfile.img

dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1

DEVICE=$(losetup --show -f testfile.img)

mkfs.btrfs -f $DEVICE

mkdir -p tmpmnt



FAILTYPE=fail_function

FAILFUNC=open_ctree

echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject

echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval

echo N > /sys/kernel/debug/$FAILTYPE/task-filter

echo 100 > /sys/kernel/debug/$FAILTYPE/probability

echo 0 > /sys/kernel/debug/$FAILTYPE/interval

echo -1 > /sys/kernel/debug/$FAILTYPE/times

echo 0 > /sys/kernel/debug/$FAILTYPE/space

echo 1 > /sys/kernel/debug/$FAILTYPE/verbose



mount -t btrfs $DEVICE tmpmnt

if [ $? -ne 0 ]

then

	echo "SUCCESS!"

else

	echo "FAILED!"

	umount tmpmnt

fi



echo > /sys/kernel/debug/$FAILTYPE/inject



rmdir tmpmnt

losetup -d $DEVICE

rm testfile.img





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

arch/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ config HAVE_OPTPROBES 
config HAVE_KPROBES_ON_FTRACE

	bool



config HAVE_KPROBE_OVERRIDE

config HAVE_FUNCTION_ERROR_INJECTION

	bool



config HAVE_NMI

arch/x86/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ config X86 
	select HAVE_KERNEL_XZ

	select HAVE_KPROBES

	select HAVE_KPROBES_ON_FTRACE

	select HAVE_KPROBE_OVERRIDE

	select HAVE_FUNCTION_ERROR_INJECTION

	select HAVE_KRETPROBES

	select HAVE_KVM

	select HAVE_LIVEPATCH			if X86_64

arch/x86/include/asm/error-injection.h

0 → 100644
+13 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _ASM_ERROR_INJECTION_H

#define _ASM_ERROR_INJECTION_H



#include <linux/compiler.h>

#include <linux/linkage.h>

#include <asm/ptrace.h>

#include <asm-generic/error-injection.h>



asmlinkage void just_return_func(void);

void override_function_with_return(struct pt_regs *regs);



#endif /* _ASM_ERROR_INJECTION_H */

arch/x86/include/asm/kprobes.h

+1 −3
Original line number Diff line number Diff line
@@ -67,9 +67,7 @@ extern const int kretprobe_blacklist_size; 
void arch_remove_kprobe(struct kprobe *p);

asmlinkage void kretprobe_trampoline(void);



#ifdef CONFIG_KPROBES_ON_FTRACE

extern void arch_ftrace_kprobe_override_function(struct pt_regs *regs);

#endif

extern void arch_kprobe_override_function(struct pt_regs *regs);



/* Architecture specific copy of original instruction*/

struct arch_specific_insn {