[PATCH v4 3/5] ubi: Add six fault injection type for testing

From: ZhaoLong Wang
Date: Fri Nov 03 2023 - 02:51:44 EST


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@xxxxxxxxxx>
---
drivers/mtd/ubi/debug.c | 30 +++++++
drivers/mtd/ubi/debug.h | 172 ++++++++++++++++++++++++++++++++++++++--
drivers/mtd/ubi/io.c | 76 +++++++++++++++++-
drivers/mtd/ubi/ubi.h | 30 ++++---
4 files changed, 287 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 3ce5265e3a16..e8aa1827f23a 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

/**
@@ -244,6 +256,12 @@ 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_read_failure", dir,
+ &fault_read_failure_attr);
+
fault_create_debugfs_attr("emulate_bitflips", dir,
&fault_bitflips_attr);

@@ -255,6 +273,18 @@ 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 7386c40474de..ccb8f5958faf 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -87,18 +87,45 @@ static inline int ubi_dbg_erase_failure(const struct ubi_device *ubi)
/* Emulate a power cut when writing EC/VID header */
#define MASK_POWER_CUT_EC (1 << 0)
#define MASK_POWER_CUT_VID (1 << 1)
+/* Emulate a power cut when writing data*/
+#define MASK_POWER_CUT_DATA (1 << 2)
+/* Emulate bit-flips */
+#define MASK_BITFLIPS (1 << 3)
+/* Emulate ecc error */
+#define MASK_ECCERR (1 << 4)
+/* Emulates -EIO during data read */
+#define MASK_READ_FAILURE (1 << 5)
+#define MASK_READ_FAILURE_EC (1 << 6)
+#define MASK_READ_FAILURE_VID (1 << 7)
+/* Emulates -EIO during data write */
+#define MASK_WRITE_FAILURE (1 << 8)
+/* Emulates -EIO during erase a PEB*/
+#define MASK_ERASE_FAILURE (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)

#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
-/* Emulate bit-flips */
-#define MASK_BITFLIPS (1 << 2)
-/* Emulates -EIO during write/erase */
-#define MASK_WRITE_FAILURE (1 << 3)
-#define MASK_ERASE_FAILURE (1 << 4)

+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);

static inline bool ubi_dbg_fail_bitflip(const struct ubi_device *ubi)
{
@@ -122,19 +149,72 @@ static inline bool ubi_dbg_fail_erase(const struct ubi_device *ubi)
}

static inline bool ubi_dbg_fail_power_cut(const struct ubi_device *ubi,
- unsigned int caller)
+ unsigned int caller)
{
if (ubi->dbg.emulate_failures & caller)
return should_fail_power_cut();
return false;
}

+static inline bool ubi_dbg_fail_read(const struct ubi_device *ubi,
+ unsigned int caller)
+{
+ if (ubi->dbg.emulate_failures & caller)
+ return should_fail_read_failure();
+ return false;
+}
+
+static inline bool ubi_dbg_fail_eccerr(const struct ubi_device *ubi)
+{
+ if (ubi->dbg.emulate_failures & MASK_ECCERR)
+ return should_fail_eccerr();
+ return false;
+}
+
+static inline bool ubi_dbg_fail_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_fail_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_fail_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_fail_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;
+}
#else /* CONFIG_MTD_UBI_FAULT_INJECTION */

#define ubi_dbg_fail_bitflip(u) false
#define ubi_dbg_fail_write(u) false
#define ubi_dbg_fail_erase(u) false
#define ubi_dbg_fail_power_cut(u,c) false
+#define ubi_dbg_fail_read(u,c) false
+#define ubi_dbg_fail_eccerr(u) false
+#define ubi_dbg_fail_ff(u,c) false
+#define ubi_dbg_fail_ff_bitflips(u,v) false
+#define ubi_dbg_fail_bad_hdr(u,c) false
+#define ubi_dbg_fail_bad_hdr_ebadmsg(u,c) false
+
#endif

/**
@@ -192,6 +272,86 @@ static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
return ubi_dbg_fail_erase(ubi);
}

+/**
+ * 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)
+{
+ return ubi_dbg_fail_eccerr(ubi);
+}
+
+/**
+ * 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)
+{
+ return ubi_dbg_fail_read(ubi, caller);
+}
+
+/**
+ * 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)
+{
+ return ubi_dbg_fail_ff(ubi, caller);
+}
+
+/**
+ * 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)
+{
+ return ubi_dbg_fail_ff_bitflips(ubi, caller);
+}
+
+/**
+ * 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)
+{
+ return ubi_dbg_fail_bad_hdr(ubi, 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)
+{
+ return ubi_dbg_fail_bad_hdr_ebadmsg(ubi, caller);
+}
+
/**
* ubi_dbg_is_bgt_disabled - if the background thread is disabled.
* @ubi: UBI device description object
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index ffa7bbf27bc2..ae2a44b44b0d 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -195,7 +195,19 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,

if (ubi_dbg_is_bitflip(ubi)) {
dbg_gen("bit-flip (emulated)");
- err = UBI_IO_BITFLIPS;
+ return UBI_IO_BITFLIPS;
+ }
+
+ 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;
}
}

@@ -782,7 +794,36 @@ 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;
+
+ 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;
+ }
+
+ return 0;
}

/**
@@ -1032,7 +1073,36 @@ 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;
+
+ 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;
+ }
+
+ return 0;
}

/**
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 41f57d5717b2..e4b547514504 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -1117,6 +1117,19 @@ static inline struct ubi_vid_hdr *ubi_get_vid_hdr(struct ubi_vid_io_buf *vidb)
return vidb->hdr;
}

+/**
+ * ubi_ro_mode - switch to read-only mode.
+ * @ubi: UBI device description object
+ */
+static inline void ubi_ro_mode(struct ubi_device *ubi)
+{
+ if (!ubi->ro_mode) {
+ ubi->ro_mode = 1;
+ ubi_warn(ubi, "switch to read-only mode");
+ dump_stack();
+ }
+}
+
/*
* This function is equivalent to 'ubi_io_read()', but @offset is relative to
* the beginning of the logical eraseblock, not to the beginning of the
@@ -1138,20 +1151,13 @@ 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
- */
-static inline void ubi_ro_mode(struct ubi_device *ubi)
-{
- if (!ubi->ro_mode) {
- ubi->ro_mode = 1;
- ubi_warn(ubi, "switch to read-only mode");
- dump_stack();
+ 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;
}
+ return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
}

/**
--
2.31.1