Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 419 insertions, 0 deletions

diff --git a/drivers/mtd/tests/nandbiterrs.c b/drivers/mtd/tests/nandbiterrs.c
new file mode 100644
index 000000000..98d7508f9
--- /dev/null
+++ b/drivers/mtd/tests/nandbiterrs.c
@@ -0,0 +1,419 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright © 2012 NetCommWireless
+ * Iwo Mergler <Iwo.Mergler@netcommwireless.com.au>
+ *
+ * Test for multi-bit error recovery on a NAND page This mostly tests the
+ * ECC controller / driver.
+ *
+ * There are two test modes:
+ *
+ *	0 - artificially inserting bit errors until the ECC fails
+ *	    This is the default method and fairly quick. It should
+ *	    be independent of the quality of the FLASH.
+ *
+ *	1 - re-writing the same pattern repeatedly until the ECC fails.
+ *	    This method relies on the physics of NAND FLASH to eventually
+ *	    generate '0' bits if '1' has been written sufficient times.
+ *	    Depending on the NAND, the first bit errors will appear after
+ *	    1000 or more writes and then will usually snowball, reaching the
+ *	    limits of the ECC quickly.
+ *
+ *	    The test stops after 10000 cycles, should your FLASH be
+ *	    exceptionally good and not generate bit errors before that. Try
+ *	    a different page in that case.
+ *
+ * Please note that neither of these tests will significantly 'use up' any
+ * FLASH endurance. Only a maximum of two erase operations will be performed.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mtd/mtd.h>
+#include <linux/err.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/slab.h>
+#include "mtd_test.h"
+
+static int dev;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static unsigned page_offset;
+module_param(page_offset, uint, S_IRUGO);
+MODULE_PARM_DESC(page_offset, "Page number relative to dev start");
+
+static unsigned seed;
+module_param(seed, uint, S_IRUGO);
+MODULE_PARM_DESC(seed, "Random seed");
+
+static int mode;
+module_param(mode, int, S_IRUGO);
+MODULE_PARM_DESC(mode, "0=incremental errors, 1=overwrite test");
+
+static unsigned max_overwrite = 10000;
+
+static loff_t   offset;     /* Offset of the page we're using. */
+static unsigned eraseblock; /* Eraseblock number for our page. */
+
+/* We assume that the ECC can correct up to a certain number
+ * of biterrors per subpage. */
+static unsigned subsize;  /* Size of subpages */
+static unsigned subcount; /* Number of subpages per page */
+
+static struct mtd_info *mtd;   /* MTD device */
+
+static uint8_t *wbuffer; /* One page write / compare buffer */
+static uint8_t *rbuffer; /* One page read buffer */
+
+/* 'random' bytes from known offsets */
+static uint8_t hash(unsigned offset)
+{
+	unsigned v = offset;
+	unsigned char c;
+	v ^= 0x7f7edfd3;
+	v = v ^ (v >> 3);
+	v = v ^ (v >> 5);
+	v = v ^ (v >> 13);
+	c = v & 0xFF;
+	/* Reverse bits of result. */
+	c = (c & 0x0F) << 4 | (c & 0xF0) >> 4;
+	c = (c & 0x33) << 2 | (c & 0xCC) >> 2;
+	c = (c & 0x55) << 1 | (c & 0xAA) >> 1;
+	return c;
+}
+
+/* Writes wbuffer to page */
+static int write_page(int log)
+{
+	if (log)
+		pr_info("write_page\n");
+
+	return mtdtest_write(mtd, offset, mtd->writesize, wbuffer);
+}
+
+/* Re-writes the data area while leaving the OOB alone. */
+static int rewrite_page(int log)
+{
+	int err = 0;
+	struct mtd_oob_ops ops = { };
+
+	if (log)
+		pr_info("rewrite page\n");
+
+	ops.mode      = MTD_OPS_RAW; /* No ECC */
+	ops.len       = mtd->writesize;
+	ops.retlen    = 0;
+	ops.ooblen    = 0;
+	ops.oobretlen = 0;
+	ops.ooboffs   = 0;
+	ops.datbuf    = wbuffer;
+	ops.oobbuf    = NULL;
+
+	err = mtd_write_oob(mtd, offset, &ops);
+	if (err || ops.retlen != mtd->writesize) {
+		pr_err("error: write_oob failed (%d)\n", err);
+		if (!err)
+			err = -EIO;
+	}
+
+	return err;
+}
+
+/* Reads page into rbuffer. Returns number of corrected bit errors (>=0)
+ * or error (<0) */
+static int read_page(int log)
+{
+	int err = 0;
+	size_t read;
+	struct mtd_ecc_stats oldstats;
+
+	if (log)
+		pr_info("read_page\n");
+
+	/* Saving last mtd stats */
+	memcpy(&oldstats, &mtd->ecc_stats, sizeof(oldstats));
+
+	err = mtd_read(mtd, offset, mtd->writesize, &read, rbuffer);
+	if (!err || err == -EUCLEAN)
+		err = mtd->ecc_stats.corrected - oldstats.corrected;
+
+	if (err < 0 || read != mtd->writesize) {
+		pr_err("error: read failed at %#llx\n", (long long)offset);
+		if (err >= 0)
+			err = -EIO;
+	}
+
+	return err;
+}
+
+/* Verifies rbuffer against random sequence */
+static int verify_page(int log)
+{
+	unsigned i, errs = 0;
+
+	if (log)
+		pr_info("verify_page\n");
+
+	for (i = 0; i < mtd->writesize; i++) {
+		if (rbuffer[i] != hash(i+seed)) {
+			pr_err("Error: page offset %u, expected %02x, got %02x\n",
+				i, hash(i+seed), rbuffer[i]);
+			errs++;
+		}
+	}
+
+	if (errs)
+		return -EIO;
+	else
+		return 0;
+}
+
+#define CBIT(v, n) ((v) & (1 << (n)))
+#define BCLR(v, n) ((v) = (v) & ~(1 << (n)))
+
+/* Finds the first '1' bit in wbuffer starting at offset 'byte'
+ * and sets it to '0'. */
+static int insert_biterror(unsigned byte)
+{
+	int bit;
+
+	while (byte < mtd->writesize) {
+		for (bit = 7; bit >= 0; bit--) {
+			if (CBIT(wbuffer[byte], bit)) {
+				BCLR(wbuffer[byte], bit);
+				pr_info("Inserted biterror @ %u/%u\n", byte, bit);
+				return 0;
+			}
+		}
+		byte++;
+	}
+	pr_err("biterror: Failed to find a '1' bit\n");
+	return -EIO;
+}
+
+/* Writes 'random' data to page and then introduces deliberate bit
+ * errors into the page, while verifying each step. */
+static int incremental_errors_test(void)
+{
+	int err = 0;
+	unsigned i;
+	unsigned errs_per_subpage = 0;
+
+	pr_info("incremental biterrors test\n");
+
+	for (i = 0; i < mtd->writesize; i++)
+		wbuffer[i] = hash(i+seed);
+
+	err = write_page(1);
+	if (err)
+		goto exit;
+
+	while (1) {
+
+		err = rewrite_page(1);
+		if (err)
+			goto exit;
+
+		err = read_page(1);
+		if (err > 0)
+			pr_info("Read reported %d corrected bit errors\n", err);
+		if (err < 0) {
+			pr_err("After %d biterrors per subpage, read reported error %d\n",
+				errs_per_subpage, err);
+			err = 0;
+			goto exit;
+		}
+
+		err = verify_page(1);
+		if (err) {
+			pr_err("ECC failure, read data is incorrect despite read success\n");
+			goto exit;
+		}
+
+		pr_info("Successfully corrected %d bit errors per subpage\n",
+			errs_per_subpage);
+
+		for (i = 0; i < subcount; i++) {
+			err = insert_biterror(i * subsize);
+			if (err < 0)
+				goto exit;
+		}
+		errs_per_subpage++;
+	}
+
+exit:
+	return err;
+}
+
+
+/* Writes 'random' data to page and then re-writes that same data repeatedly.
+   This eventually develops bit errors (bits written as '1' will slowly become
+   '0'), which are corrected as far as the ECC is capable of. */
+static int overwrite_test(void)
+{
+	int err = 0;
+	unsigned i;
+	unsigned max_corrected = 0;
+	unsigned opno = 0;
+	/* We don't expect more than this many correctable bit errors per
+	 * page. */
+	#define MAXBITS 512
+	static unsigned bitstats[MAXBITS]; /* bit error histogram. */
+
+	memset(bitstats, 0, sizeof(bitstats));
+
+	pr_info("overwrite biterrors test\n");
+
+	for (i = 0; i < mtd->writesize; i++)
+		wbuffer[i] = hash(i+seed);
+
+	err = write_page(1);
+	if (err)
+		goto exit;
+
+	while (opno < max_overwrite) {
+
+		err = write_page(0);
+		if (err)
+			break;
+
+		err = read_page(0);
+		if (err >= 0) {
+			if (err >= MAXBITS) {
+				pr_info("Implausible number of bit errors corrected\n");
+				err = -EIO;
+				break;
+			}
+			bitstats[err]++;
+			if (err > max_corrected) {
+				max_corrected = err;
+				pr_info("Read reported %d corrected bit errors\n",
+					err);
+			}
+		} else { /* err < 0 */
+			pr_info("Read reported error %d\n", err);
+			err = 0;
+			break;
+		}
+
+		err = verify_page(0);
+		if (err) {
+			bitstats[max_corrected] = opno;
+			pr_info("ECC failure, read data is incorrect despite read success\n");
+			break;
+		}
+
+		err = mtdtest_relax();
+		if (err)
+			break;
+
+		opno++;
+	}
+
+	/* At this point bitstats[0] contains the number of ops with no bit
+	 * errors, bitstats[1] the number of ops with 1 bit error, etc. */
+	pr_info("Bit error histogram (%d operations total):\n", opno);
+	for (i = 0; i < max_corrected; i++)
+		pr_info("Page reads with %3d corrected bit errors: %d\n",
+			i, bitstats[i]);
+
+exit:
+	return err;
+}
+
+static int __init mtd_nandbiterrs_init(void)
+{
+	int err = 0;
+
+	printk("\n");
+	printk(KERN_INFO "==================================================\n");
+	pr_info("MTD device: %d\n", dev);
+
+	mtd = get_mtd_device(NULL, dev);
+	if (IS_ERR(mtd)) {
+		err = PTR_ERR(mtd);
+		pr_err("error: cannot get MTD device\n");
+		goto exit_mtddev;
+	}
+
+	if (!mtd_type_is_nand(mtd)) {
+		pr_info("this test requires NAND flash\n");
+		err = -ENODEV;
+		goto exit_nand;
+	}
+
+	pr_info("MTD device size %llu, eraseblock=%u, page=%u, oob=%u\n",
+		(unsigned long long)mtd->size, mtd->erasesize,
+		mtd->writesize, mtd->oobsize);
+
+	subsize  = mtd->writesize >> mtd->subpage_sft;
+	subcount = mtd->writesize / subsize;
+
+	pr_info("Device uses %d subpages of %d bytes\n", subcount, subsize);
+
+	offset     = (loff_t)page_offset * mtd->writesize;
+	eraseblock = mtd_div_by_eb(offset, mtd);
+
+	pr_info("Using page=%u, offset=%llu, eraseblock=%u\n",
+		page_offset, offset, eraseblock);
+
+	wbuffer = kmalloc(mtd->writesize, GFP_KERNEL);
+	if (!wbuffer) {
+		err = -ENOMEM;
+		goto exit_wbuffer;
+	}
+
+	rbuffer = kmalloc(mtd->writesize, GFP_KERNEL);
+	if (!rbuffer) {
+		err = -ENOMEM;
+		goto exit_rbuffer;
+	}
+
+	err = mtdtest_erase_eraseblock(mtd, eraseblock);
+	if (err)
+		goto exit_error;
+
+	if (mode == 0)
+		err = incremental_errors_test();
+	else
+		err = overwrite_test();
+
+	if (err)
+		goto exit_error;
+
+	/* We leave the block un-erased in case of test failure. */
+	err = mtdtest_erase_eraseblock(mtd, eraseblock);
+	if (err)
+		goto exit_error;
+
+	err = -EIO;
+	pr_info("finished successfully.\n");
+	printk(KERN_INFO "==================================================\n");
+
+exit_error:
+	kfree(rbuffer);
+exit_rbuffer:
+	kfree(wbuffer);
+exit_wbuffer:
+	/* Nothing */
+exit_nand:
+	put_mtd_device(mtd);
+exit_mtddev:
+	return err;
+}
+
+static void __exit mtd_nandbiterrs_exit(void)
+{
+	return;
+}
+
+module_init(mtd_nandbiterrs_init);
+module_exit(mtd_nandbiterrs_exit);
+
+MODULE_DESCRIPTION("NAND bit error recovery test");
+MODULE_AUTHOR("Iwo Mergler");
+MODULE_LICENSE("GPL");