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From:   ZhaoLong Wang <wangzhaolong1@huawei.com>
To:     <richard@nod.at>, <miquel.raynal@bootlin.com>, <vigneshr@ti.com>
CC:     <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <chengzhihao1@huawei.com>, <wangzhaolong1@huawei.com>,
        <yi.zhang@huawei.com>
Subject: [PATCH V2 3/5] ubi: Add six fault injection type for testing
Date:   Tue, 18 Jul 2023 16:51:17 +0800
Message-ID: <20230718085119.3885747-4-wangzhaolong1@huawei.com>
In-Reply-To: <20230718085119.3885747-1-wangzhaolong1@huawei.com>
References: <20230718085119.3885747-1-wangzhaolong1@huawei.com>
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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 | 132 ++++++++++++++++++++++++++++++++++++++--
 drivers/mtd/ubi/io.c    |  75 ++++++++++++++++++++++-
 drivers/mtd/ubi/ubi.h   |  31 ++++++----
 4 files changed, 248 insertions(+), 20 deletions(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 7826bc8166e8..016a861c5029 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 6bc698b38e35..29fbd971964a 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -85,20 +85,47 @@ static inline int ubi_dbg_erase_failure(const struct ubi_device *ubi)
  * precisely control the type and process of fault injection.
  */
 /* Emulate a power cut when writing EC/VID header */
-#define MASK_POWER_CUT_EC	(1 << 1)
-#define MASK_POWER_CUT_VID	(1 << 2)
+#define MASK_POWER_CUT_EC		(1 << 0)
+#define MASK_POWER_CUT_VID		(1 << 1)
 
 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+/* Emulate a power cut when writing data*/
+#define MASK_POWER_CUT_DATA		(1 << 2)
 /* Emulate bit-flips */
-#define MASK_BITFLIPS		(1 << 3)
-/* Emulates -EIO during write/erase */
-#define MASK_WRITE_FAILURE	(1 << 4)
-#define MASK_ERASE_FAILURE	(1 << 5)
+#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)
 
+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)
 {
@@ -192,6 +219,99 @@ static inline bool ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
 	return ubi_dbg_fail_erase(ubi);
 }
 
+#ifdef CONFIG_MTD_UBI_FAULT_INJECTION
+/**
+ * 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_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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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
 /**
  * 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..059032132bdd 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -197,6 +197,19 @@ int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 			dbg_gen("bit-flip (emulated)");
 			err = UBI_IO_BITFLIPS;
 		}
+#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;
+		}
+#endif
 	}
 
 	return err;
@@ -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;
 }
 
 /**
@@ -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;
 }
 
 /**
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 41f57d5717b2..36d46425ed4c 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -1117,18 +1117,6 @@ static inline struct ubi_vid_hdr *ubi_get_vid_hdr(struct ubi_vid_io_buf *vidb)
 	return vidb->hdr;
 }
 
-/*
- * 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
- * physical eraseblock.
- */
-static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
-				   int pnum, int offset, int len)
-{
-	ubi_assert(offset >= 0);
-	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
@@ -1154,6 +1142,25 @@ static inline void ubi_ro_mode(struct ubi_device *ubi)
 	}
 }
 
+/*
+ * 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
+ * physical eraseblock.
+ */
+static inline int ubi_io_read_data(struct ubi_device *ubi, 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_read(ubi, buf, pnum, offset + ubi->leb_start, len);
+}
+
 /**
  * vol_id2idx - get table index by volume ID.
  * @ubi: UBI device description object
-- 
2.31.1