Commit 663faf9f authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Alexei Starovoitov
Browse files

error-injection: Add injectable error types 



Add injectable error types for each error-injectable function.

One motivation of error injection test is to find software flaws,
mistakes or mis-handlings of expectable errors. If we find such
flaws by the test, that is a program bug, so we need to fix it.

But if the tester miss input the error (e.g. just return success
code without processing anything), it causes unexpected behavior
even if the caller is correctly programmed to handle any errors.
That is not what we want to test by error injection.

To clarify what type of errors the caller must expect for each
injectable function, this introduces injectable error types:

 - EI_ETYPE_NULL : means the function will return NULL if it
		    fails. No ERR_PTR, just a NULL.
 - EI_ETYPE_ERRNO : means the function will return -ERRNO
		    if it fails.
 - EI_ETYPE_ERRNO_NULL : means the function will return -ERRNO
		       (ERR_PTR) or NULL.

ALLOW_ERROR_INJECTION() macro is expanded to get one of
NULL, ERRNO, ERRNO_NULL to record the error type for
each function. e.g.

 ALLOW_ERROR_INJECTION(open_ctree, ERRNO)

This error types are shown in debugfs as below.

  ====
  / # cat /sys/kernel/debug/error_injection/list
  open_ctree [btrfs]	ERRNO
  io_ctl_init [btrfs]	ERRNO
  ====

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 540adea3

fs/btrfs/disk-io.c

+1 −1
Original line number Diff line number Diff line
@@ -3124,7 +3124,7 @@ recovery_tree_root: 
		goto fail_block_groups;

	goto retry_root_backup;

}

ALLOW_ERROR_INJECTION(open_ctree);

ALLOW_ERROR_INJECTION(open_ctree, ERRNO);



static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)

{

fs/btrfs/free-space-cache.c

+1 −1
Original line number Diff line number Diff line
@@ -333,7 +333,7 @@ static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode, 


	return 0;

}

ALLOW_ERROR_INJECTION(io_ctl_init);

ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);



static void io_ctl_free(struct btrfs_io_ctl *io_ctl)

{

include/asm-generic/error-injection.h

+19 −4
Original line number Diff line number Diff line
@@ -3,17 +3,32 @@ 
#define _ASM_GENERIC_ERROR_INJECTION_H



#if defined(__KERNEL__) && !defined(__ASSEMBLY__)

enum {

	EI_ETYPE_NONE,		/* Dummy value for undefined case */

	EI_ETYPE_NULL,		/* Return NULL if failure */

	EI_ETYPE_ERRNO,		/* Return -ERRNO if failure */

	EI_ETYPE_ERRNO_NULL,	/* Return -ERRNO or NULL if failure */

};



struct error_injection_entry {

	unsigned long	addr;

	int		etype;

};



#ifdef CONFIG_FUNCTION_ERROR_INJECTION

/*

 * Whitelist ganerating macro. Specify functions which can be

 * error-injectable using this macro.

 */

#define ALLOW_ERROR_INJECTION(fname)					\

static unsigned long __used						\

#define ALLOW_ERROR_INJECTION(fname, _etype)				\

static struct error_injection_entry __used				\

	__attribute__((__section__("_error_injection_whitelist")))	\

	_eil_addr_##fname = (unsigned long)fname;

	_eil_addr_##fname = {						\

		.addr = (unsigned long)fname,				\

		.etype = EI_ETYPE_##_etype,				\

	};

#else

#define ALLOW_ERROR_INJECTION(fname)

#define ALLOW_ERROR_INJECTION(fname, _etype)

#endif

#endif

include/asm-generic/vmlinux.lds.h

+1 −1
Original line number Diff line number Diff line
@@ -137,7 +137,7 @@ 
#endif



#ifdef CONFIG_FUNCTION_ERROR_INJECTION

#define ERROR_INJECT_WHITELIST()	. = ALIGN(8);			      \

#define ERROR_INJECT_WHITELIST()	STRUCT_ALIGN();			      \

			VMLINUX_SYMBOL(__start_error_injection_whitelist) = .;\

			KEEP(*(_error_injection_whitelist))		      \

			VMLINUX_SYMBOL(__stop_error_injection_whitelist) = .;

include/linux/error-injection.h

+6 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <asm/error-injection.h>



extern bool within_error_injection_list(unsigned long addr);

extern int get_injectable_error_type(unsigned long addr);



#else /* !CONFIG_FUNCTION_ERROR_INJECTION */
@@ -16,6 +17,11 @@ static inline bool within_error_injection_list(unsigned long addr) 
	return false;

}



static inline int get_injectable_error_type(unsigned long addr)

{

	return EI_ETYPE_NONE;

}



#endif



#endif /* _LINUX_ERROR_INJECTION_H */

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