[PATCH 0/5] ubi: Enhanced fault injection capability for the UBI driver

[PATCH 0/5] ubi: Enhanced fault injection capability for the UBI driver

[ZhaoLong Wang]

The existing fault injection capability of UBI is too simple.
It uses hard-coded fault probability values and lacks other
configurable options. As a result, these interfaces are difficult
to use when digging defects in the abnormal path of code and
reproducing some problems.

The kernel provides a powerful fault injection framework, which
provides rich configurable fault injection attributes during runtime.
So it can be used to improve the fault injection capability of the 
UBI driver.

This series of patches refactor the existing fault injection interface
and add some fault injection types to help testers and developers
find potential problems in the code.

ZhaoLong Wang (5):
  ubi: Using the Fault Injection Framework to refactor the debugfs
    interface
  ubi: Split io_failures into write_failure and erase_failure
  ubi: Add six fault injection type for testing
  ubi: Reserve sufficient buffer length for the input mask
  mtd: Add several functions to the fail_function list

 drivers/mtd/mtdcore.c   |   6 +-
 drivers/mtd/ubi/Kconfig |   8 ++
 drivers/mtd/ubi/debug.c | 185 +++++++++++++++++++-------------------
 drivers/mtd/ubi/debug.h | 190 ++++++++++++++++++++++++++++++++++++----
 drivers/mtd/ubi/io.c    | 101 ++++++++++++++++++---
 drivers/mtd/ubi/ubi.h   |  68 +++++---------
 6 files changed, 390 insertions(+), 168 deletions(-)

-- 
2.31.1


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Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH -next 1/5] ubi: Using the Fault Injection Framework to refactor the debugfs interface

[ZhaoLong Wang]

To make debug parameters configurable at run time, use the
fault injection framework to reconstruct the debugfs interface.

Now, the file emulate_failures and fault_attr files control whether
to enable fault emmulation.

The file emulate_failures receives a mask that controls type and
process of fault injection. Generally, for ease of use, you can
directly enter a mask with all 1s.

echo 0xffff > /sys/kernel/debug/ubi/ubi0/emulate_failures

And you need to configure other fault-injection capabilities for
testing purpose:

echo 100 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/probability
echo 15 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/space
echo 2 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/verbose
echo -1 > /sys/kernel/debug/ubi/fault_inject/emulate_power_cut/times

The CONFIG_MTD_UBI_FAULT_INJECTION to enable the Fault Injection is
added to kconfig.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/ubi/Kconfig |   8 +++
 drivers/mtd/ubi/debug.c | 147 ++++++++++++++++------------------------
 drivers/mtd/ubi/debug.h |  91 ++++++++++++++++++++-----
 drivers/mtd/ubi/io.c    |  10 ++-
 drivers/mtd/ubi/ubi.h   |  37 ++--------
 5 files changed, 150 insertions(+), 143 deletions(-)

diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 2ed77b7b3fcb..0a0180a3a54b 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -103,5 +103,13 @@ config MTD_UBI_BLOCK
 	   When selected, this feature will be built in the UBI driver.
 
 	   If in doubt, say "N".
+config MTD_UBI_FAULT_INJECTION
+	bool "Fault injection capability of UBI device"
+	default n
+	depends on FAULT_INJECTION_DEBUG_FS
+	help
+	   this option enable fault-injection support for UBI devices for
+	   testing purposes and is only interesting to developers.
 
+	   If unsure, say N.
 endif # MTD_UBI
diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 27168f511d6d..2550522e2cd5 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -10,6 +10,23 @@
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/seq_file.h>
+#include <linux/fault-inject.h>
+
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+static DECLARE_FAULT_ATTR(fault_bitflips_attr);
+static DECLARE_FAULT_ATTR(fault_io_failures_attr);
+static DECLARE_FAULT_ATTR(fault_power_cut_attr);
+
+#define FAIL_ACTION(name, fault_attr)			\
+bool should_fail_##name(void)				\
+{							\
+	return should_fail(&fault_attr, 1);		\
+}
+
+FAIL_ACTION(bitflips,		fault_bitflips_attr)
+FAIL_ACTION(io_failures,	fault_io_failures_attr)
+FAIL_ACTION(power_cut,		fault_power_cut_attr)
+#endif
 
 
 /**
@@ -212,6 +229,31 @@ void ubi_dump_mkvol_req(const struct ubi_mkvol_req *req)
  */
 static struct dentry *dfs_rootdir;
 
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+static void dfs_create_fault_entry(struct dentry *parent)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir("fault_inject", parent);
+	if (IS_ERR_OR_NULL(dir)) {
+		int err = dir ? PTR_ERR(dir) : -ENODEV;
+
+		pr_warn("UBI error: cannot create \"fault_inject\" debugfs directory, error %d\n",
+			err);
+		return;
+	}
+
+	fault_create_debugfs_attr("emulate_bitflips", dir,
+				  &fault_bitflips_attr);
+
+	fault_create_debugfs_attr("emulate_io_failures", dir,
+				  &fault_io_failures_attr);
+
+	fault_create_debugfs_attr("emulate_power_cut", dir,
+				  &fault_power_cut_attr);
+}
+#endif
+
 /**
  * ubi_debugfs_init - create UBI debugfs directory.
  *
@@ -232,6 +274,10 @@ int ubi_debugfs_init(void)
 		return err;
 	}
 
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+	dfs_create_fault_entry(dfs_rootdir);
+#endif
+
 	return 0;
 }
 
@@ -268,27 +314,12 @@ static ssize_t dfs_file_read(struct file *file, char __user *user_buf,
 		val = d->chk_fastmap;
 	else if (dent == d->dfs_disable_bgt)
 		val = d->disable_bgt;
-	else if (dent == d->dfs_emulate_bitflips)
-		val = d->emulate_bitflips;
-	else if (dent == d->dfs_emulate_io_failures)
-		val = d->emulate_io_failures;
-	else if (dent == d->dfs_emulate_power_cut) {
-		snprintf(buf, sizeof(buf), "%u\n", d->emulate_power_cut);
+	else if (dent == d->dfs_emulate_failures) {
+		snprintf(buf, sizeof(buf), "%u\n", d->emulate_failures);
 		count = simple_read_from_buffer(user_buf, count, ppos,
 						buf, strlen(buf));
 		goto out;
-	} else if (dent == d->dfs_power_cut_min) {
-		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_min);
-		count = simple_read_from_buffer(user_buf, count, ppos,
-						buf, strlen(buf));
-		goto out;
-	} else if (dent == d->dfs_power_cut_max) {
-		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_max);
-		count = simple_read_from_buffer(user_buf, count, ppos,
-						buf, strlen(buf));
-		goto out;
-	}
-	else {
+	} else {
 		count = -EINVAL;
 		goto out;
 	}
@@ -330,20 +361,10 @@ static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
 		goto out;
 	}
 
-	if (dent == d->dfs_power_cut_min) {
-		if (kstrtouint(buf, 0, &d->power_cut_min) != 0)
-			count = -EINVAL;
-		goto out;
-	} else if (dent == d->dfs_power_cut_max) {
-		if (kstrtouint(buf, 0, &d->power_cut_max) != 0)
+	if (dent == d->dfs_emulate_failures) {
+		if (kstrtouint(buf, 0, &d->emulate_failures) != 0)
 			count = -EINVAL;
 		goto out;
-	} else if (dent == d->dfs_emulate_power_cut) {
-		if (kstrtoint(buf, 0, &val) != 0)
-			count = -EINVAL;
-		else
-			d->emulate_power_cut = val;
-		goto out;
 	}
 
 	if (buf[0] == '1')
@@ -363,10 +384,6 @@ static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
 		d->chk_fastmap = val;
 	else if (dent == d->dfs_disable_bgt)
 		d->disable_bgt = val;
-	else if (dent == d->dfs_emulate_bitflips)
-		d->emulate_bitflips = val;
-	else if (dent == d->dfs_emulate_io_failures)
-		d->emulate_io_failures = val;
 	else
 		count = -EINVAL;
 
@@ -386,6 +403,7 @@ static const struct file_operations dfs_fops = {
 	.owner  = THIS_MODULE,
 };
 
+
 /* As long as the position is less then that total number of erase blocks,
  * we still have more to print.
  */
@@ -533,32 +551,14 @@ int ubi_debugfs_init_dev(struct ubi_device *ubi)
 						 d->dfs_dir, (void *)ubi_num,
 						 &dfs_fops);
 
-	d->dfs_emulate_bitflips = debugfs_create_file("tst_emulate_bitflips",
-						      mode, d->dfs_dir,
-						      (void *)ubi_num,
-						      &dfs_fops);
-
-	d->dfs_emulate_io_failures = debugfs_create_file("tst_emulate_io_failures",
-							 mode, d->dfs_dir,
-							 (void *)ubi_num,
-							 &dfs_fops);
-
-	d->dfs_emulate_power_cut = debugfs_create_file("tst_emulate_power_cut",
-						       mode, d->dfs_dir,
-						       (void *)ubi_num,
-						       &dfs_fops);
-
-	d->dfs_power_cut_min = debugfs_create_file("tst_emulate_power_cut_min",
-						   mode, d->dfs_dir,
-						   (void *)ubi_num, &dfs_fops);
-
-	d->dfs_power_cut_max = debugfs_create_file("tst_emulate_power_cut_max",
-						   mode, d->dfs_dir,
-						   (void *)ubi_num, &dfs_fops);
-
 	debugfs_create_file("detailed_erase_block_info", S_IRUSR, d->dfs_dir,
 			    (void *)ubi_num, &eraseblk_count_fops);
 
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+	d->dfs_emulate_failures = debugfs_create_file("emulate_failures", mode,
+						      d->dfs_dir, (void *)ubi_num,
+						      &dfs_fops);
+#endif
 	return 0;
 }
 
@@ -571,36 +571,3 @@ void ubi_debugfs_exit_dev(struct ubi_device *ubi)
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		debugfs_remove_recursive(ubi->dbg.dfs_dir);
 }
-
-/**
- * ubi_dbg_power_cut - emulate a power cut if it is time to do so
- * @ubi: UBI device description object
- * @caller: Flags set to indicate from where the function is being called
- *
- * Returns non-zero if a power cut was emulated, zero if not.
- */
-int ubi_dbg_power_cut(struct ubi_device *ubi, int caller)
-{
-	unsigned int range;
-
-	if ((ubi->dbg.emulate_power_cut & caller) == 0)
-		return 0;
-
-	if (ubi->dbg.power_cut_counter == 0) {
-		ubi->dbg.power_cut_counter = ubi->dbg.power_cut_min;
-
-		if (ubi->dbg.power_cut_max > ubi->dbg.power_cut_min) {
-			range = ubi->dbg.power_cut_max - ubi->dbg.power_cut_min;
-			ubi->dbg.power_cut_counter += get_random_u32_below(range);
-		}
-		return 0;
-	}
-
-	ubi->dbg.power_cut_counter--;
-	if (ubi->dbg.power_cut_counter)
-		return 0;
-
-	ubi_msg(ubi, "XXXXXXXXXXXXXXX emulating a power cut XXXXXXXXXXXXXXXX");
-	ubi_ro_mode(ubi);
-	return 1;
-}
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index 23676f32b681..bf843433a901 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -8,6 +8,18 @@
 #ifndef __UBI_DEBUG_H__
 #define __UBI_DEBUG_H__
 
+/**
+ * MASK_XXX: Mask for emulate_failures in ubi_debug_info.The mask is used to
+ * precisely control the type and process of fault injection.
+ */
+/* Emulate bit-flips */
+#define MASK_BITFLIPS		(1 << 0)
+/* Emulates -EIO during write/erase */
+#define MASK_IO_FAILURE		(1 << 1)
+/* Emulate a power cut when writing EC/VID header */
+#define MASK_POWER_CUT_EC	(1 << 2)
+#define MASK_POWER_CUT_VID	(1 << 3)
+
 void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
 void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr);
 void ubi_dump_vid_hdr(const struct ubi_vid_hdr *vid_hdr);
@@ -64,46 +76,90 @@ static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
 	return ubi->dbg.disable_bgt;
 }
 
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+
+extern bool should_fail_bitflips(void);
+extern bool should_fail_io_failures(void);
+extern bool should_fail_power_cut(void);
+
 /**
  * ubi_dbg_is_bitflip - if it is time to emulate a bit-flip.
  * @ubi: UBI device description object
  *
- * Returns non-zero if a bit-flip should be emulated, otherwise returns zero.
+ * Returns true if a bit-flip should be emulated, otherwise returns false.
  */
-static inline int ubi_dbg_is_bitflip(const struct ubi_device *ubi)
+static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
 {
-	if (ubi->dbg.emulate_bitflips)
-		return !get_random_u32_below(200);
-	return 0;
+	if (ubi->dbg.emulate_failures & MASK_BITFLIPS)
+		return should_fail_bitflips();
+	return false;
 }
 
 /**
  * ubi_dbg_is_write_failure - if it is time to emulate a write failure.
  * @ubi: UBI device description object
  *
- * Returns non-zero if a write failure should be emulated, otherwise returns
- * zero.
+ * Returns true if a write failure should be emulated, otherwise returns
+ * false.
  */
-static inline int ubi_dbg_is_write_failure(const struct ubi_device *ubi)
+static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
 {
-	if (ubi->dbg.emulate_io_failures)
-		return !get_random_u32_below(500);
-	return 0;
+	if (ubi->dbg.emulate_failures & MASK_IO_FAILURE)
+		return should_fail_io_failures();
+	return false;
 }
 
 /**
  * ubi_dbg_is_erase_failure - if its time to emulate an erase failure.
  * @ubi: UBI device description object
  *
- * Returns non-zero if an erase failure should be emulated, otherwise returns
- * zero.
+ * Returns true if an erase failure should be emulated, otherwise returns
+ * false.
  */
-static inline int ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
+static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
+{
+	if (ubi->dbg.emulate_failures & MASK_IO_FAILURE)
+		return should_fail_io_failures();
+	return false;
+}
+
+/**
+ * ubi_dbg_power_cut - if it is time to emulate power cut.
+ * @ubi: UBI device description object
+ *
+ * Returns true if power cut should be emulated, otherwise returns false.
+ */
+static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
+				     unsigned int caller)
+{
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_power_cut();
+	return false;
+}
+
+#else /* CONFIG_MTD_UBI_FAULT_INJECTION */
+
+static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
+{
+	return false;
+}
+
+static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
+{
+	return false;
+}
+
+static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
+{
+	return false;
+}
+
+static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
+				     unsigned int caller)
 {
-	if (ubi->dbg.emulate_io_failures)
-		return !get_random_u32_below(400);
-	return 0;
+	return false;
 }
+#endif
 
 static inline int ubi_dbg_chk_io(const struct ubi_device *ubi)
 {
@@ -125,5 +181,4 @@ static inline void ubi_enable_dbg_chk_fastmap(struct ubi_device *ubi)
 	ubi->dbg.chk_fastmap = 1;
 }
 
-int ubi_dbg_power_cut(struct ubi_device *ubi, int caller);
 #endif /* !__UBI_DEBUG_H__ */
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 01b644861253..906ad0811d52 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -821,8 +821,11 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 	if (err)
 		return err;
 
-	if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
+	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_EC)) {
+		ubi_warn(ubi, "XXXXX emulating a power cut when writing EC header XXXXX");
+		ubi_ro_mode(ubi);
 		return -EROFS;
+	}
 
 	err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 	return err;
@@ -1071,8 +1074,11 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 	if (err)
 		return err;
 
-	if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
+	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_VID)) {
+		ubi_warn(ubi, "XXXXX emulating a power cut when writing VID header XXXXX");
+		ubi_ro_mode(ubi);
 		return -EROFS;
+	}
 
 	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
 			   ubi->vid_hdr_alsize);
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index c8f1bd4fa100..e20e9a6f9c05 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -142,17 +142,6 @@ enum {
 	UBI_BAD_FASTMAP,
 };
 
-/*
- * Flags for emulate_power_cut in ubi_debug_info
- *
- * POWER_CUT_EC_WRITE: Emulate a power cut when writing an EC header
- * POWER_CUT_VID_WRITE: Emulate a power cut when writing a VID header
- */
-enum {
-	POWER_CUT_EC_WRITE = 0x01,
-	POWER_CUT_VID_WRITE = 0x02,
-};
-
 /**
  * struct ubi_vid_io_buf - VID buffer used to read/write VID info to/from the
  *			   flash.
@@ -395,46 +384,28 @@ struct ubi_volume_desc {
  * @chk_io: if UBI I/O extra checks are enabled
  * @chk_fastmap: if UBI fastmap extra checks are enabled
  * @disable_bgt: disable the background task for testing purposes
- * @emulate_bitflips: emulate bit-flips for testing purposes
- * @emulate_io_failures: emulate write/erase failures for testing purposes
- * @emulate_power_cut: emulate power cut for testing purposes
- * @power_cut_counter: count down for writes left until emulated power cut
- * @power_cut_min: minimum number of writes before emulating a power cut
- * @power_cut_max: maximum number of writes until emulating a power cut
+ * @emulate_failures: emulate failures for testing purposes
  * @dfs_dir_name: name of debugfs directory containing files of this UBI device
  * @dfs_dir: direntry object of the UBI device debugfs directory
  * @dfs_chk_gen: debugfs knob to enable UBI general extra checks
  * @dfs_chk_io: debugfs knob to enable UBI I/O extra checks
  * @dfs_chk_fastmap: debugfs knob to enable UBI fastmap extra checks
  * @dfs_disable_bgt: debugfs knob to disable the background task
- * @dfs_emulate_bitflips: debugfs knob to emulate bit-flips
- * @dfs_emulate_io_failures: debugfs knob to emulate write/erase failures
- * @dfs_emulate_power_cut: debugfs knob to emulate power cuts
- * @dfs_power_cut_min: debugfs knob for minimum writes before power cut
- * @dfs_power_cut_max: debugfs knob for maximum writes until power cut
+ * @dfs_emulate_failures: debugfs entry to control the fault injection type
  */
 struct ubi_debug_info {
 	unsigned int chk_gen:1;
 	unsigned int chk_io:1;
 	unsigned int chk_fastmap:1;
 	unsigned int disable_bgt:1;
-	unsigned int emulate_bitflips:1;
-	unsigned int emulate_io_failures:1;
-	unsigned int emulate_power_cut:2;
-	unsigned int power_cut_counter;
-	unsigned int power_cut_min;
-	unsigned int power_cut_max;
+	unsigned int emulate_failures;
 	char dfs_dir_name[UBI_DFS_DIR_LEN + 1];
 	struct dentry *dfs_dir;
 	struct dentry *dfs_chk_gen;
 	struct dentry *dfs_chk_io;
 	struct dentry *dfs_chk_fastmap;
 	struct dentry *dfs_disable_bgt;
-	struct dentry *dfs_emulate_bitflips;
-	struct dentry *dfs_emulate_io_failures;
-	struct dentry *dfs_emulate_power_cut;
-	struct dentry *dfs_power_cut_min;
-	struct dentry *dfs_power_cut_max;
+	struct dentry *dfs_emulate_failures;
 };
 
 /**
-- 
2.31.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH -next 2/5] ubi: Split io_failures into write_failure and erase_failure

[ZhaoLong Wang]

The emulate_io_failures debugfs entry controls both write
failure and erase failure. This patch split io_failures
to write_failure and erase_failure.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/ubi/debug.c | 14 +++++++++-----
 drivers/mtd/ubi/debug.h | 18 ++++++++++--------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 2550522e2cd5..9c92bd59b639 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -14,7 +14,8 @@
 
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 static DECLARE_FAULT_ATTR(fault_bitflips_attr);
-static DECLARE_FAULT_ATTR(fault_io_failures_attr);
+static DECLARE_FAULT_ATTR(fault_write_failure_attr);
+static DECLARE_FAULT_ATTR(fault_erase_failure_attr);
 static DECLARE_FAULT_ATTR(fault_power_cut_attr);
 
 #define FAIL_ACTION(name, fault_attr)			\
@@ -24,7 +25,8 @@ bool should_fail_##name(void)				\
 }
 
 FAIL_ACTION(bitflips,		fault_bitflips_attr)
-FAIL_ACTION(io_failures,	fault_io_failures_attr)
+FAIL_ACTION(write_failure,	fault_write_failure_attr)
+FAIL_ACTION(erase_failure,	fault_erase_failure_attr)
 FAIL_ACTION(power_cut,		fault_power_cut_attr)
 #endif
 
@@ -246,8 +248,11 @@ static void dfs_create_fault_entry(struct dentry *parent)
 	fault_create_debugfs_attr("emulate_bitflips", dir,
 				  &fault_bitflips_attr);
 
-	fault_create_debugfs_attr("emulate_io_failures", dir,
-				  &fault_io_failures_attr);
+	fault_create_debugfs_attr("emulate_write_failure", dir,
+				  &fault_write_failure_attr);
+
+	fault_create_debugfs_attr("emulate_erase_failure", dir,
+				  &fault_erase_failure_attr);
 
 	fault_create_debugfs_attr("emulate_power_cut", dir,
 				  &fault_power_cut_attr);
@@ -277,7 +282,6 @@ int ubi_debugfs_init(void)
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 	dfs_create_fault_entry(dfs_rootdir);
 #endif
-
 	return 0;
 }
 
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index bf843433a901..2486fcab4205 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -15,10 +15,11 @@
 /* Emulate bit-flips */
 #define MASK_BITFLIPS		(1 << 0)
 /* Emulates -EIO during write/erase */
-#define MASK_IO_FAILURE		(1 << 1)
+#define MASK_WRITE_FAILURE	(1 << 1)
+#define MASK_ERASE_FAILURE	(1 << 2)
 /* Emulate a power cut when writing EC/VID header */
-#define MASK_POWER_CUT_EC	(1 << 2)
-#define MASK_POWER_CUT_VID	(1 << 3)
+#define MASK_POWER_CUT_EC	(1 << 3)
+#define MASK_POWER_CUT_VID	(1 << 4)
 
 void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
 void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr);
@@ -79,7 +80,8 @@ static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 
 extern bool should_fail_bitflips(void);
-extern bool should_fail_io_failures(void);
+extern bool should_fail_write_failure(void);
+extern bool should_fail_erase_failure(void);
 extern bool should_fail_power_cut(void);
 
 /**
@@ -104,8 +106,8 @@ static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
  */
 static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
 {
-	if (ubi->dbg.emulate_failures & MASK_IO_FAILURE)
-		return should_fail_io_failures();
+	if (ubi->dbg.emulate_failures & MASK_WRITE_FAILURE)
+		return should_fail_write_failure();
 	return false;
 }
 
@@ -118,8 +120,8 @@ static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
  */
 static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
 {
-	if (ubi->dbg.emulate_failures & MASK_IO_FAILURE)
-		return should_fail_io_failures();
+	if (ubi->dbg.emulate_failures & MASK_ERASE_FAILURE)
+		return should_fail_erase_failure();
 	return false;
 }
 
-- 
2.31.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH -next 3/5] ubi: Add six fault injection type for testing

[ZhaoLong Wang]

This commit adds six fault injection type for testing to cover the
abnormal path of the UBI driver.

Inject the following faults when the UBI reads the LEB:
 +----------------------------+-----------------------------------+
 |    Interface name          |       emulate behavior            |
 +----------------------------+-----------------------------------+
 |  emulate_eccerr            | ECC error                         |
 +----------------------------+-----------------------------------+
 |  emulate_read_failure      | read failure                      |
 |----------------------------+-----------------------------------+
 |  emulate_io_ff             | read content as all FF            |
 |----------------------------+-----------------------------------+
 |  emulate_io_ff_bitflips    | content FF with MTD err reported  |
 +----------------------------+-----------------------------------+
 |  emulate_bad_hdr           | bad leb header                    |
 |----------------------------+-----------------------------------+
 |  emulate_bad_hdr_ebadmsg   | bad header with ECC err           |
 +----------------------------+-----------------------------------+

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/ubi/debug.c |  30 ++++++++++
 drivers/mtd/ubi/debug.h | 123 +++++++++++++++++++++++++++++++++++-----
 drivers/mtd/ubi/io.c    |  91 +++++++++++++++++++++++++----
 drivers/mtd/ubi/ubi.h   |  31 ++++++----
 4 files changed, 240 insertions(+), 35 deletions(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 9c92bd59b639..0c58cbabe9fc 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -13,10 +13,16 @@
 #include <linux/fault-inject.h>
 
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+static DECLARE_FAULT_ATTR(fault_eccerr_attr);
 static DECLARE_FAULT_ATTR(fault_bitflips_attr);
+static DECLARE_FAULT_ATTR(fault_read_failure_attr);
 static DECLARE_FAULT_ATTR(fault_write_failure_attr);
 static DECLARE_FAULT_ATTR(fault_erase_failure_attr);
 static DECLARE_FAULT_ATTR(fault_power_cut_attr);
+static DECLARE_FAULT_ATTR(fault_io_ff_attr);
+static DECLARE_FAULT_ATTR(fault_io_ff_bitflips_attr);
+static DECLARE_FAULT_ATTR(fault_bad_hdr_attr);
+static DECLARE_FAULT_ATTR(fault_bad_hdr_ebadmsg_attr);
 
 #define FAIL_ACTION(name, fault_attr)			\
 bool should_fail_##name(void)				\
@@ -24,10 +30,16 @@ bool should_fail_##name(void)				\
 	return should_fail(&fault_attr, 1);		\
 }
 
+FAIL_ACTION(eccerr,		fault_eccerr_attr)
 FAIL_ACTION(bitflips,		fault_bitflips_attr)
+FAIL_ACTION(read_failure,	fault_read_failure_attr)
 FAIL_ACTION(write_failure,	fault_write_failure_attr)
 FAIL_ACTION(erase_failure,	fault_erase_failure_attr)
 FAIL_ACTION(power_cut,		fault_power_cut_attr)
+FAIL_ACTION(io_ff,		fault_io_ff_attr)
+FAIL_ACTION(io_ff_bitflips,	fault_io_ff_bitflips_attr)
+FAIL_ACTION(bad_hdr,		fault_bad_hdr_attr)
+FAIL_ACTION(bad_hdr_ebadmsg,	fault_bad_hdr_ebadmsg_attr)
 #endif
 
 
@@ -245,9 +257,15 @@ static void dfs_create_fault_entry(struct dentry *parent)
 		return;
 	}
 
+	fault_create_debugfs_attr("emulate_eccerr", dir,
+				  &fault_eccerr_attr);
+
 	fault_create_debugfs_attr("emulate_bitflips", dir,
 				  &fault_bitflips_attr);
 
+	fault_create_debugfs_attr("emulate_read_failure", dir,
+				  &fault_read_failure_attr);
+
 	fault_create_debugfs_attr("emulate_write_failure", dir,
 				  &fault_write_failure_attr);
 
@@ -256,6 +274,18 @@ static void dfs_create_fault_entry(struct dentry *parent)
 
 	fault_create_debugfs_attr("emulate_power_cut", dir,
 				  &fault_power_cut_attr);
+
+	fault_create_debugfs_attr("emulate_io_ff", dir,
+				  &fault_io_ff_attr);
+
+	fault_create_debugfs_attr("emulate_io_ff_bitflips", dir,
+				  &fault_io_ff_bitflips_attr);
+
+	fault_create_debugfs_attr("emulate_bad_hdr", dir,
+				  &fault_bad_hdr_attr);
+
+	fault_create_debugfs_attr("emulate_bad_hdr_ebadmsg", dir,
+				  &fault_bad_hdr_ebadmsg_attr);
 }
 #endif
 
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index 2486fcab4205..8272c2b93dd4 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -13,13 +13,34 @@
  * precisely control the type and process of fault injection.
  */
 /* Emulate bit-flips */
-#define MASK_BITFLIPS		(1 << 0)
-/* Emulates -EIO during write/erase */
-#define MASK_WRITE_FAILURE	(1 << 1)
-#define MASK_ERASE_FAILURE	(1 << 2)
+#define MASK_BITFLIPS			(1 << 0)
+/* Emulate ecc error */
+#define MASK_ECCERR			(1 << 1)
+/* Emulates -EIO during data read */
+#define MASK_READ_FAILURE		(1 << 2)
+#define MASK_READ_FAILURE_EC		(1 << 3)
+#define MASK_READ_FAILURE_VID		(1 << 4)
+/* Emulates -EIO during data write */
+#define MASK_WRITE_FAILURE		(1 << 5)
+/* Emulates -EIO during erase a PEB*/
+#define MASK_ERASE_FAILURE		(1 << 6)
 /* Emulate a power cut when writing EC/VID header */
-#define MASK_POWER_CUT_EC	(1 << 3)
-#define MASK_POWER_CUT_VID	(1 << 4)
+#define MASK_POWER_CUT_EC		(1 << 7)
+#define MASK_POWER_CUT_VID		(1 << 8)
+/* Emulate a power cut when writing data*/
+#define MASK_POWER_CUT_DATA		(1 << 9)
+/* Return UBI_IO_FF when reading EC/VID header */
+#define MASK_IO_FF_EC			(1 << 10)
+#define MASK_IO_FF_VID			(1 << 11)
+/* Return UBI_IO_FF_BITFLIPS when reading EC/VID header */
+#define MASK_IO_FF_BITFLIPS_EC		(1 << 12)
+#define MASK_IO_FF_BITFLIPS_VID		(1 << 13)
+/* Return UBI_IO_BAD_HDR when reading EC/VID header */
+#define MASK_BAD_HDR_EC			(1 << 14)
+#define MASK_BAD_HDR_VID		(1 << 15)
+/* Return UBI_IO_BAD_HDR_EBADMSG when reading EC/VID header */
+#define MASK_BAD_HDR_EBADMSG_EC		(1 << 16)
+#define MASK_BAD_HDR_EBADMSG_VID	(1 << 17)
 
 void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
 void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr);
@@ -79,10 +100,16 @@ static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
 
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 
+extern bool should_fail_eccerr(void);
 extern bool should_fail_bitflips(void);
+extern bool should_fail_read_failure(void);
 extern bool should_fail_write_failure(void);
 extern bool should_fail_erase_failure(void);
 extern bool should_fail_power_cut(void);
+extern bool should_fail_io_ff(void);
+extern bool should_fail_io_ff_bitflips(void);
+extern bool should_fail_bad_hdr(void);
+extern bool should_fail_bad_hdr_ebadmsg(void);
 
 /**
  * ubi_dbg_is_bitflip - if it is time to emulate a bit-flip.
@@ -97,6 +124,34 @@ static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
 	return false;
 }
 
+/**
+ * ubi_dbg_is_eccerr - if it is time to emulate ECC error.
+ * @ubi: UBI device description object
+ *
+ * Returns true if a ECC error should be emulated, otherwise returns false.
+ */
+static inline bool ubi_dbg_is_eccerr(const struct ubi_device *ubi)
+{
+	if (ubi->dbg.emulate_failures & MASK_ECCERR)
+		return should_fail_eccerr();
+	return false;
+}
+
+/**
+ * ubi_dbg_is_read_failure - if it is time to emulate a read failure.
+ * @ubi: UBI device description object
+ *
+ * Returns true if a read failure should be emulated, otherwise returns
+ * false.
+ */
+static inline bool ubi_dbg_is_read_failure(const struct ubi_device *ubi,
+					   unsigned int caller)
+{
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_read_failure();
+	return false;
+}
+
 /**
  * ubi_dbg_is_write_failure - if it is time to emulate a write failure.
  * @ubi: UBI device description object
@@ -139,28 +194,70 @@ static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
 	return false;
 }
 
-#else /* CONFIG_MTD_UBI_FAULT_INJECTION */
-
-static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
+/**
+ * ubi_dbg_is_ff - if it is time to emulate that read region is only 0xFF.
+ * @ubi: UBI device description object
+ *
+ * Returns true if read region should be emulated 0xFF, otherwise
+ * returns false.
+ */
+static inline bool ubi_dbg_is_ff(const struct ubi_device *ubi,
+				 unsigned int caller)
 {
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_io_ff();
 	return false;
 }
 
-static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
+/**
+ * ubi_dbg_is_ff_bitflips - if it is time to emulate that read region is only 0xFF
+ * with error reported by the MTD driver
+ *
+ * @ubi: UBI device description object
+ *
+ * Returns true if read region should be emulated 0xFF and error
+ * reported by the MTD driver, otherwise returns false.
+ */
+static inline bool ubi_dbg_is_ff_bitflips(const struct ubi_device *ubi,
+					  unsigned int caller)
 {
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_io_ff_bitflips();
 	return false;
 }
 
-static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
+/**
+ * ubi_dbg_is_bad_hdr - if it is time to emulate a bad header
+ * @ubi: UBI device description object
+ *
+ * Returns true if a bad header error should be emulated, otherwise
+ * returns false.
+ */
+static inline bool ubi_dbg_is_bad_hdr(const struct ubi_device *ubi,
+				      unsigned int caller)
 {
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_bad_hdr();
 	return false;
 }
 
-static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
-				     unsigned int caller)
+/**
+ * ubi_dbg_is_bad_hdr_ebadmsg - if it is time to emulate a bad header with
+ * ECC error.
+ *
+ * @ubi: UBI device description object
+ *
+ * Returns true if a bad header with ECC error should be emulated, otherwise
+ * returns false.
+ */
+static inline bool ubi_dbg_is_bad_hdr_ebadmsg(const struct ubi_device *ubi,
+					      unsigned int caller)
 {
+	if (ubi->dbg.emulate_failures & caller)
+		return should_fail_bad_hdr_ebadmsg();
 	return false;
 }
+
 #endif
 
 static inline int ubi_dbg_chk_io(const struct ubi_device *ubi)
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 906ad0811d52..e64914c3cc8d 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -192,11 +192,24 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 		}
 	} else {
 		ubi_assert(len == read);
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+		if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE)) {
+			ubi_warn(ubi, "cannot read %d bytes from PEB %d:%d (emulated)",
+				 len, pnum, offset);
+			return -EIO;
+		}
+
+		if (ubi_dbg_is_eccerr(ubi)) {
+			ubi_warn(ubi, "ECC error (emulated) while reading %d bytes from PEB %d:%d, read %zd bytes",
+				 len, pnum, offset, read);
+			return -EBADMSG;
+		}
 
 		if (ubi_dbg_is_bitflip(ubi)) {
 			dbg_gen("bit-flip (emulated)");
 			err = UBI_IO_BITFLIPS;
 		}
+#endif
 	}
 
 	return err;
@@ -259,14 +272,14 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 		if (err)
 			return err;
 	}
-
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 	if (ubi_dbg_is_write_failure(ubi)) {
 		ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
 			len, pnum, offset);
 		dump_stack();
 		return -EIO;
 	}
-
+#endif
 	addr = (loff_t)pnum * ubi->peb_size + offset;
 	err = mtd_write(ubi->mtd, addr, len, &written, buf);
 	if (err) {
@@ -339,12 +352,12 @@ static int do_sync_erase(struct ubi_device *ubi, int pnum)
 	err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 	if (err)
 		return err;
-
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 	if (ubi_dbg_is_erase_failure(ubi)) {
 		ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
 		return -EIO;
 	}
-
+#endif
 	return 0;
 }
 
@@ -782,7 +795,36 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 	 * If there was %-EBADMSG, but the header CRC is still OK, report about
 	 * a bit-flip to force scrubbing on this PEB.
 	 */
-	return read_err ? UBI_IO_BITFLIPS : 0;
+	if (read_err)
+		return UBI_IO_BITFLIPS;
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+	if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE_EC)) {
+		ubi_warn(ubi, "cannot read EC header from PEB %d(emulated)",
+			 pnum);
+		return -EIO;
+	}
+
+	if (ubi_dbg_is_ff(ubi, MASK_IO_FF_EC)) {
+		ubi_warn(ubi, "bit-all-ff (emulated)");
+		return UBI_IO_FF;
+	}
+
+	if (ubi_dbg_is_ff_bitflips(ubi, MASK_IO_FF_BITFLIPS_EC)) {
+		ubi_warn(ubi, "bit-all-ff with error reported by MTD driver (emulated)");
+		return UBI_IO_FF_BITFLIPS;
+	}
+
+	if (ubi_dbg_is_bad_hdr(ubi, MASK_BAD_HDR_EC)) {
+		ubi_warn(ubi, "bad_hdr (emulated)");
+		return UBI_IO_BAD_HDR;
+	}
+
+	if (ubi_dbg_is_bad_hdr_ebadmsg(ubi, MASK_BAD_HDR_EBADMSG_EC)) {
+		ubi_warn(ubi, "bad_hdr with ECC error (emulated)");
+		return UBI_IO_BAD_HDR_EBADMSG;
+	}
+#endif
+	return 0;
 }
 
 /**
@@ -820,13 +862,13 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 	err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 	if (err)
 		return err;
-
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_EC)) {
 		ubi_warn(ubi, "XXXXX emulating a power cut when writing EC header XXXXX");
 		ubi_ro_mode(ubi);
 		return -EROFS;
 	}
-
+#endif
 	err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 	return err;
 }
@@ -1032,7 +1074,36 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 		return -EINVAL;
 	}
 
-	return read_err ? UBI_IO_BITFLIPS : 0;
+	if (read_err)
+		return UBI_IO_BITFLIPS;
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+	if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE_VID)) {
+		ubi_warn(ubi, "cannot read VID header from PEB %d(emulated)",
+			 pnum);
+		return -EIO;
+	}
+
+	if (ubi_dbg_is_ff(ubi, MASK_IO_FF_VID)) {
+		ubi_warn(ubi, "bit-all-ff (emulated)\n");
+		return UBI_IO_FF;
+	}
+
+	if (ubi_dbg_is_ff_bitflips(ubi, MASK_IO_FF_BITFLIPS_VID)) {
+		ubi_warn(ubi, "bit-all-ff with error reported by MTD driver (emulated)\n");
+		return UBI_IO_FF_BITFLIPS;
+	}
+
+	if (ubi_dbg_is_bad_hdr(ubi, MASK_BAD_HDR_VID)) {
+		ubi_warn(ubi, "bad_hdr (emulated)\n");
+		return UBI_IO_BAD_HDR;
+	}
+
+	if (ubi_dbg_is_bad_hdr_ebadmsg(ubi, MASK_BAD_HDR_EBADMSG_VID)) {
+		ubi_warn(ubi, "bad_hdr with ECC error (emulated)\n");
+		return UBI_IO_BAD_HDR_EBADMSG;
+	}
+#endif
+	return 0;
 }
 
 /**
@@ -1073,13 +1144,13 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 	err = self_check_vid_hdr(ubi, pnum, vid_hdr);
 	if (err)
 		return err;
-
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
 	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_VID)) {
 		ubi_warn(ubi, "XXXXX emulating a power cut when writing VID header XXXXX");
 		ubi_ro_mode(ubi);
 		return -EROFS;
 	}
-
+#endif
 	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
 			   ubi->vid_hdr_alsize);
 	return err;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index e20e9a6f9c05..7ff55a74b313 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -1107,18 +1107,6 @@ static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
 	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
 }
 
-/*
- * This function is equivalent to 'ubi_io_write()', but @offset is relative to
- * the beginning of the logical eraseblock, not to the beginning of the
- * physical eraseblock.
- */
-static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
-				    int pnum, int offset, int len)
-{
-	ubi_assert(offset >= 0);
-	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
-}
-
 /**
  * ubi_ro_mode - switch to read-only mode.
  * @ubi: UBI device description object
@@ -1132,6 +1120,25 @@ static inline void ubi_ro_mode(struct ubi_device *ubi)
 	}
 }
 
+/*
+ * This function is equivalent to 'ubi_io_write()', but @offset is relative to
+ * the beginning of the logical eraseblock, not to the beginning of the
+ * physical eraseblock.
+ */
+static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
+				    int pnum, int offset, int len)
+{
+	ubi_assert(offset >= 0);
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_DATA)) {
+		ubi_warn(ubi, "XXXXX emulating a power cut when writing data XXXXX");
+		ubi_ro_mode(ubi);
+		return -EROFS;
+	}
+#endif
+	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
+}
+
 /**
  * vol_id2idx - get table index by volume ID.
  * @ubi: UBI device description object
-- 
2.31.1


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Re: [PATCH -next 3/5] ubi: Add six fault injection type for testing

[Zhihao Cheng]

> This commit adds six fault injection type for testing to cover the
> abnormal path of the UBI driver.
> 
[...]
>   
> diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
> index 2486fcab4205..8272c2b93dd4 100644
> --- a/drivers/mtd/ubi/debug.h
> +++ b/drivers/mtd/ubi/debug.h
> @@ -13,13 +13,34 @@
>    * precisely control the type and process of fault injection.
>    */
>   /* Emulate bit-flips */
> -#define MASK_BITFLIPS		(1 << 0)
> -/* Emulates -EIO during write/erase */
> -#define MASK_WRITE_FAILURE	(1 << 1)
> -#define MASK_ERASE_FAILURE	(1 << 2)
> +#define MASK_BITFLIPS			(1 << 0)
> +/* Emulate ecc error */
> +#define MASK_ECCERR			(1 << 1)
> +/* Emulates -EIO during data read */
> +#define MASK_READ_FAILURE		(1 << 2)
> +#define MASK_READ_FAILURE_EC		(1 << 3)
> +#define MASK_READ_FAILURE_VID		(1 << 4)
> +/* Emulates -EIO during data write */
> +#define MASK_WRITE_FAILURE		(1 << 5)
> +/* Emulates -EIO during erase a PEB*/
> +#define MASK_ERASE_FAILURE		(1 << 6)
>   /* Emulate a power cut when writing EC/VID header */
> -#define MASK_POWER_CUT_EC	(1 << 3)
> -#define MASK_POWER_CUT_VID	(1 << 4)
> +#define MASK_POWER_CUT_EC		(1 << 7)
> +#define MASK_POWER_CUT_VID		(1 << 8)
> +/* Emulate a power cut when writing data*/
> +#define MASK_POWER_CUT_DATA		(1 << 9)
> +/* Return UBI_IO_FF when reading EC/VID header */
> +#define MASK_IO_FF_EC			(1 << 10)
> +#define MASK_IO_FF_VID			(1 << 11)
> +/* Return UBI_IO_FF_BITFLIPS when reading EC/VID header */
> +#define MASK_IO_FF_BITFLIPS_EC		(1 << 12)
> +#define MASK_IO_FF_BITFLIPS_VID		(1 << 13)
> +/* Return UBI_IO_BAD_HDR when reading EC/VID header */
> +#define MASK_BAD_HDR_EC			(1 << 14)
> +#define MASK_BAD_HDR_VID		(1 << 15)
> +/* Return UBI_IO_BAD_HDR_EBADMSG when reading EC/VID header */
> +#define MASK_BAD_HDR_EBADMSG_EC		(1 << 16)
> +#define MASK_BAD_HDR_EBADMSG_VID	(1 << 17)
>   
>   void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
>   void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr);
> @@ -79,10 +100,16 @@ static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
>   
>   #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
>   
> +extern bool should_fail_eccerr(void);
>   extern bool should_fail_bitflips(void);
> +extern bool should_fail_read_failure(void);
>   extern bool should_fail_write_failure(void);
>   extern bool should_fail_erase_failure(void);
>   extern bool should_fail_power_cut(void);
> +extern bool should_fail_io_ff(void);
> +extern bool should_fail_io_ff_bitflips(void);
> +extern bool should_fail_bad_hdr(void);
> +extern bool should_fail_bad_hdr_ebadmsg(void);
>   
>   /**
>    * ubi_dbg_is_bitflip - if it is time to emulate a bit-flip.
> @@ -97,6 +124,34 @@ static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
>   	return false;
>   }
>   
> +/**
> + * ubi_dbg_is_eccerr - if it is time to emulate ECC error.
> + * @ubi: UBI device description object
> + *
> + * Returns true if a ECC error should be emulated, otherwise returns false.
> + */
> +static inline bool ubi_dbg_is_eccerr(const struct ubi_device *ubi)
> +{
> +	if (ubi->dbg.emulate_failures & MASK_ECCERR)
> +		return should_fail_eccerr();
> +	return false;
> +}
> +
> +/**
> + * ubi_dbg_is_read_failure - if it is time to emulate a read failure.
> + * @ubi: UBI device description object
> + *
> + * Returns true if a read failure should be emulated, otherwise returns
> + * false.
> + */
> +static inline bool ubi_dbg_is_read_failure(const struct ubi_device *ubi,
> +					   unsigned int caller)
> +{
> +	if (ubi->dbg.emulate_failures & caller)
> +		return should_fail_read_failure();
> +	return false;
> +}
> +
>   /**
>    * ubi_dbg_is_write_failure - if it is time to emulate a write failure.
>    * @ubi: UBI device description object
> @@ -139,28 +194,70 @@ static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
>   	return false;
>   }
>   
> -#else /* CONFIG_MTD_UBI_FAULT_INJECTION */

Why not keeping double function definations style, then you don't need 
to check 'CONFIG_MTD_UBI_FAULT_INJECTION' in other *.c(eg. io.c).
> -
> -static inline bool ubi_dbg_is_bitflip(const struct ubi_device *ubi)
> +/**
> + * ubi_dbg_is_ff - if it is time to emulate that read region is only 0xFF.
> + * @ubi: UBI device description object
> + *
> + * Returns true if read region should be emulated 0xFF, otherwise
> + * returns false.
> + */
> +static inline bool ubi_dbg_is_ff(const struct ubi_device *ubi,
> +				 unsigned int caller)
>   {
> +	if (ubi->dbg.emulate_failures & caller)
> +		return should_fail_io_ff();
>   	return false;
>   }
>   
> -static inline bool ubi_dbg_is_write_failure(const struct ubi_device *ubi)
> +/**
> + * ubi_dbg_is_ff_bitflips - if it is time to emulate that read region is only 0xFF
> + * with error reported by the MTD driver
> + *
> + * @ubi: UBI device description object
> + *
> + * Returns true if read region should be emulated 0xFF and error
> + * reported by the MTD driver, otherwise returns false.
> + */
> +static inline bool ubi_dbg_is_ff_bitflips(const struct ubi_device *ubi,
> +					  unsigned int caller)
>   {
> +	if (ubi->dbg.emulate_failures & caller)
> +		return should_fail_io_ff_bitflips();
>   	return false;
>   }
>   
> -static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
> +/**
> + * ubi_dbg_is_bad_hdr - if it is time to emulate a bad header
> + * @ubi: UBI device description object
> + *
> + * Returns true if a bad header error should be emulated, otherwise
> + * returns false.
> + */
> +static inline bool ubi_dbg_is_bad_hdr(const struct ubi_device *ubi,
> +				      unsigned int caller)
>   {
> +	if (ubi->dbg.emulate_failures & caller)
> +		return should_fail_bad_hdr();
>   	return false;
>   }
>   
> -static inline bool ubi_dbg_power_cut(const struct ubi_device *ubi,
> -				     unsigned int caller)
> +/**
> + * ubi_dbg_is_bad_hdr_ebadmsg - if it is time to emulate a bad header with
> + * ECC error.
> + *
> + * @ubi: UBI device description object
> + *
> + * Returns true if a bad header with ECC error should be emulated, otherwise
> + * returns false.
> + */
> +static inline bool ubi_dbg_is_bad_hdr_ebadmsg(const struct ubi_device *ubi,
> +					      unsigned int caller)
>   {
> +	if (ubi->dbg.emulate_failures & caller)
> +		return should_fail_bad_hdr_ebadmsg();
>   	return false;
>   }
> +
>   #endif
>   
>   static inline int ubi_dbg_chk_io(const struct ubi_device *ubi)
> diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
> index 906ad0811d52..e64914c3cc8d 100644
> --- a/drivers/mtd/ubi/io.c
> +++ b/drivers/mtd/ubi/io.c
> @@ -192,11 +192,24 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
>   		}
>   	} else {
>   		ubi_assert(len == read);
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
> +		if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE)) {
> +			ubi_warn(ubi, "cannot read %d bytes from PEB %d:%d (emulated)",
> +				 len, pnum, offset);
> +			return -EIO;
> +		}
> +
> +		if (ubi_dbg_is_eccerr(ubi)) {
> +			ubi_warn(ubi, "ECC error (emulated) while reading %d bytes from PEB %d:%d, read %zd bytes",
> +				 len, pnum, offset, read);
> +			return -EBADMSG;
> +		}
>   
>   		if (ubi_dbg_is_bitflip(ubi)) {
>   			dbg_gen("bit-flip (emulated)");
>   			err = UBI_IO_BITFLIPS;
>   		}
> +#endif
>   	}
>   
>   	return err;
> @@ -259,14 +272,14 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
>   		if (err)
>   			return err;
>   	}
> -
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
>   	if (ubi_dbg_is_write_failure(ubi)) {
>   		ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
>   			len, pnum, offset);
>   		dump_stack();
>   		return -EIO;
>   	}
> -
> +#endif
>   	addr = (loff_t)pnum * ubi->peb_size + offset;
>   	err = mtd_write(ubi->mtd, addr, len, &written, buf);
>   	if (err) {
> @@ -339,12 +352,12 @@ static int do_sync_erase(struct ubi_device *ubi, int pnum)
>   	err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
>   	if (err)
>   		return err;
> -
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
>   	if (ubi_dbg_is_erase_failure(ubi)) {
>   		ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
>   		return -EIO;
>   	}
> -
> +#endif
>   	return 0;
>   }
>   
> @@ -782,7 +795,36 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
>   	 * If there was %-EBADMSG, but the header CRC is still OK, report about
>   	 * a bit-flip to force scrubbing on this PEB.
>   	 */
> -	return read_err ? UBI_IO_BITFLIPS : 0;
> +	if (read_err)
> +		return UBI_IO_BITFLIPS;
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
> +	if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE_EC)) {
> +		ubi_warn(ubi, "cannot read EC header from PEB %d(emulated)",
> +			 pnum);
> +		return -EIO;
> +	}
> +
> +	if (ubi_dbg_is_ff(ubi, MASK_IO_FF_EC)) {
> +		ubi_warn(ubi, "bit-all-ff (emulated)");
> +		return UBI_IO_FF;
> +	}
> +
> +	if (ubi_dbg_is_ff_bitflips(ubi, MASK_IO_FF_BITFLIPS_EC)) {
> +		ubi_warn(ubi, "bit-all-ff with error reported by MTD driver (emulated)");
> +		return UBI_IO_FF_BITFLIPS;
> +	}
> +
> +	if (ubi_dbg_is_bad_hdr(ubi, MASK_BAD_HDR_EC)) {
> +		ubi_warn(ubi, "bad_hdr (emulated)");
> +		return UBI_IO_BAD_HDR;
> +	}
> +
> +	if (ubi_dbg_is_bad_hdr_ebadmsg(ubi, MASK_BAD_HDR_EBADMSG_EC)) {
> +		ubi_warn(ubi, "bad_hdr with ECC error (emulated)");
> +		return UBI_IO_BAD_HDR_EBADMSG;
> +	}
> +#endif
> +	return 0;
>   }
>   
>   /**
> @@ -820,13 +862,13 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
>   	err = self_check_ec_hdr(ubi, pnum, ec_hdr);
>   	if (err)
>   		return err;
> -
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
>   	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_EC)) {
>   		ubi_warn(ubi, "XXXXX emulating a power cut when writing EC header XXXXX");
>   		ubi_ro_mode(ubi);
>   		return -EROFS;
>   	}
> -
> +#endif
>   	err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
>   	return err;
>   }
> @@ -1032,7 +1074,36 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
>   		return -EINVAL;
>   	}
>   
> -	return read_err ? UBI_IO_BITFLIPS : 0;
> +	if (read_err)
> +		return UBI_IO_BITFLIPS;
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
> +	if (ubi_dbg_is_read_failure(ubi, MASK_READ_FAILURE_VID)) {
> +		ubi_warn(ubi, "cannot read VID header from PEB %d(emulated)",
> +			 pnum);
> +		return -EIO;
> +	}
> +
> +	if (ubi_dbg_is_ff(ubi, MASK_IO_FF_VID)) {
> +		ubi_warn(ubi, "bit-all-ff (emulated)\n");
> +		return UBI_IO_FF;
> +	}
> +
> +	if (ubi_dbg_is_ff_bitflips(ubi, MASK_IO_FF_BITFLIPS_VID)) {
> +		ubi_warn(ubi, "bit-all-ff with error reported by MTD driver (emulated)\n");
> +		return UBI_IO_FF_BITFLIPS;
> +	}
> +
> +	if (ubi_dbg_is_bad_hdr(ubi, MASK_BAD_HDR_VID)) {
> +		ubi_warn(ubi, "bad_hdr (emulated)\n");
> +		return UBI_IO_BAD_HDR;
> +	}
> +
> +	if (ubi_dbg_is_bad_hdr_ebadmsg(ubi, MASK_BAD_HDR_EBADMSG_VID)) {
> +		ubi_warn(ubi, "bad_hdr with ECC error (emulated)\n");
> +		return UBI_IO_BAD_HDR_EBADMSG;
> +	}
> +#endif
> +	return 0;
>   }
>   
>   /**
> @@ -1073,13 +1144,13 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
>   	err = self_check_vid_hdr(ubi, pnum, vid_hdr);
>   	if (err)
>   		return err;
> -
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
>   	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_VID)) {
>   		ubi_warn(ubi, "XXXXX emulating a power cut when writing VID header XXXXX");
>   		ubi_ro_mode(ubi);
>   		return -EROFS;
>   	}
> -
> +#endif
>   	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
>   			   ubi->vid_hdr_alsize);
>   	return err;
> diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
> index e20e9a6f9c05..7ff55a74b313 100644
> --- a/drivers/mtd/ubi/ubi.h
> +++ b/drivers/mtd/ubi/ubi.h
> @@ -1107,18 +1107,6 @@ static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
>   	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
>   }
>   
> -/*
> - * This function is equivalent to 'ubi_io_write()', but @offset is relative to
> - * the beginning of the logical eraseblock, not to the beginning of the
> - * physical eraseblock.
> - */
> -static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
> -				    int pnum, int offset, int len)
> -{
> -	ubi_assert(offset >= 0);
> -	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
> -}
> -
>   /**
>    * ubi_ro_mode - switch to read-only mode.
>    * @ubi: UBI device description object
> @@ -1132,6 +1120,25 @@ static inline void ubi_ro_mode(struct ubi_device *ubi)
>   	}
>   }
>   
> +/*
> + * This function is equivalent to 'ubi_io_write()', but @offset is relative to
> + * the beginning of the logical eraseblock, not to the beginning of the
> + * physical eraseblock.
> + */
> +static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
> +				    int pnum, int offset, int len)
> +{
> +	ubi_assert(offset >= 0);
> +#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
> +	if (ubi_dbg_power_cut(ubi, MASK_POWER_CUT_DATA)) {
> +		ubi_warn(ubi, "XXXXX emulating a power cut when writing data XXXXX");
> +		ubi_ro_mode(ubi);
> +		return -EROFS;
> +	}
> +#endif
> +	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
> +}
> +
>   /**
>    * vol_id2idx - get table index by volume ID.
>    * @ubi: UBI device description object
> 


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[PATCH -next 4/5] ubi: Reserve sufficient buffer length for the input mask

[ZhaoLong Wang]

Because the mask received by the emulate_failures interface
is a 32-bit unsigned integer, ensure that there is sufficient
buffer length to receive and display this value.

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/ubi/debug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 0c58cbabe9fc..eafeb10e57bf 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -332,7 +332,7 @@ static ssize_t dfs_file_read(struct file *file, char __user *user_buf,
 	struct dentry *dent = file->f_path.dentry;
 	struct ubi_device *ubi;
 	struct ubi_debug_info *d;
-	char buf[8];
+	char buf[12];
 	int val;
 
 	ubi = ubi_get_device(ubi_num);
@@ -381,7 +381,7 @@ static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
 	struct ubi_device *ubi;
 	struct ubi_debug_info *d;
 	size_t buf_size;
-	char buf[8] = {0};
+	char buf[14] = {0};
 	int val;
 
 	ubi = ubi_get_device(ubi_num);
-- 
2.31.1


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[PATCH -next 5/5] mtd: Add several functions to the fail_function list

[ZhaoLong Wang]

add mtd_read(), mtd_write(), mtd_erase(), mtd_block_markbad() to
fail_function list for testing purpose

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
---
 drivers/mtd/mtdcore.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 0feacb9fbdac..58558088d44e 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -29,6 +29,7 @@
 #include <linux/debugfs.h>
 #include <linux/nvmem-provider.h>
 #include <linux/root_dev.h>
+#include <linux/error-injection.h>
 
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
@@ -1371,6 +1372,7 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_erase);
+ALLOW_ERROR_INJECTION(mtd_erase, ERRNO);
 
 /*
  * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
@@ -1468,6 +1470,7 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_read);
+ALLOW_ERROR_INJECTION(mtd_read, ERRNO);
 
 int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 	      const u_char *buf)
@@ -1484,6 +1487,7 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_write);
+ALLOW_ERROR_INJECTION(mtd_write, ERRNO);
 
 /*
  * In blackbox flight recorder like scenarios we want to make successful writes
@@ -2304,7 +2308,7 @@ int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mtd_block_markbad);
-
+ALLOW_ERROR_INJECTION(mtd_block_markbad, ERRNO);
 /*
  * default_mtd_writev - the default writev method
  * @mtd: mtd device description object pointer
-- 
2.31.1


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Re: [PATCH 0/5] ubi: Enhanced fault injection capability for the UBI driver

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "ZhaoLong Wang" <wangzhaolong1@huawei.com>
> The existing fault injection capability of UBI is too simple.
> It uses hard-coded fault probability values and lacks other
> configurable options. As a result, these interfaces are difficult
> to use when digging defects in the abnormal path of code and
> reproducing some problems.
> 
> The kernel provides a powerful fault injection framework, which
> provides rich configurable fault injection attributes during runtime.
> So it can be used to improve the fault injection capability of the
> UBI driver.
> 
> This series of patches refactor the existing fault injection interface
> and add some fault injection types to help testers and developers
> find potential problems in the code.

In general I like having some new and advanced way to test UBI.
But your patches seem to remove the old interface from debugfs,
this will cause breakage of existing test scripts.

So please keep the old interface too.

Thanks,
//richard

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Re: [PATCH 0/5] ubi: Enhanced fault injection capability for the UBI driver

[ZhaoLong Wang]

Thank you very much for replying to my email. I agree with you.

I'll tweak my patch in the next few weeks, try to keep the old interface and
be compatible with the new interface.

Best Regards
ZhaoLong Wang

在 2023/4/22 5:18, Richard Weinberger 写道:
> ----- Ursprüngliche Mail -----
>> Von: "ZhaoLong Wang" <wangzhaolong1@huawei.com>
>> The existing fault injection capability of UBI is too simple.
>> It uses hard-coded fault probability values and lacks other
>> configurable options. As a result, these interfaces are difficult
>> to use when digging defects in the abnormal path of code and
>> reproducing some problems.
>>
>> The kernel provides a powerful fault injection framework, which
>> provides rich configurable fault injection attributes during runtime.
>> So it can be used to improve the fault injection capability of the
>> UBI driver.
>>
>> This series of patches refactor the existing fault injection interface
>> and add some fault injection types to help testers and developers
>> find potential problems in the code.
> In general I like having some new and advanced way to test UBI.
> But your patches seem to remove the old interface from debugfs,
> this will cause breakage of existing test scripts.
>
> So please keep the old interface too.
>
> Thanks,
> //richard
>

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