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, 458 insertions, 0 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
new file mode 100644
index 000000000..1da7ef06a
--- /dev/null
+++ b/drivers/mtd/mtdoops.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MTD Oops/Panic logger
+ *
+ * Copyright © 2007 Nokia Corporation. All rights reserved.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/timekeeping.h>
+#include <linux/mtd/mtd.h>
+#include <linux/kmsg_dump.h>
+
+/* Maximum MTD partition size */
+#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
+
+static unsigned long record_size = 4096;
+module_param(record_size, ulong, 0400);
+MODULE_PARM_DESC(record_size,
+		"record size for MTD OOPS pages in bytes (default 4096)");
+
+static char mtddev[80];
+module_param_string(mtddev, mtddev, 80, 0400);
+MODULE_PARM_DESC(mtddev,
+		"name or index number of the MTD device to use");
+
+static int dump_oops = 1;
+module_param(dump_oops, int, 0600);
+MODULE_PARM_DESC(dump_oops,
+		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
+
+#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00  /* Original */
+#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00  /* Adds the timestamp */
+
+struct mtdoops_hdr {
+	u32 seq;
+	u32 magic;
+	ktime_t timestamp;
+} __packed;
+
+static struct mtdoops_context {
+	struct kmsg_dumper dump;
+
+	int mtd_index;
+	struct work_struct work_erase;
+	struct work_struct work_write;
+	struct mtd_info *mtd;
+	int oops_pages;
+	int nextpage;
+	int nextcount;
+	unsigned long *oops_page_used;
+
+	unsigned long oops_buf_busy;
+	void *oops_buf;
+} oops_cxt;
+
+static void mark_page_used(struct mtdoops_context *cxt, int page)
+{
+	set_bit(page, cxt->oops_page_used);
+}
+
+static void mark_page_unused(struct mtdoops_context *cxt, int page)
+{
+	clear_bit(page, cxt->oops_page_used);
+}
+
+static int page_is_used(struct mtdoops_context *cxt, int page)
+{
+	return test_bit(page, cxt->oops_page_used);
+}
+
+static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
+{
+	struct mtd_info *mtd = cxt->mtd;
+	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
+	u32 start_page = start_page_offset / record_size;
+	u32 erase_pages = mtd->erasesize / record_size;
+	struct erase_info erase;
+	int ret;
+	int page;
+
+	erase.addr = offset;
+	erase.len = mtd->erasesize;
+
+	ret = mtd_erase(mtd, &erase);
+	if (ret) {
+		pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
+			(unsigned long long)erase.addr,
+			(unsigned long long)erase.len, mtddev);
+		return ret;
+	}
+
+	/* Mark pages as unused */
+	for (page = start_page; page < start_page + erase_pages; page++)
+		mark_page_unused(cxt, page);
+
+	return 0;
+}
+
+static void mtdoops_erase(struct mtdoops_context *cxt)
+{
+	struct mtd_info *mtd = cxt->mtd;
+	int i = 0, j, ret, mod;
+
+	/* We were unregistered */
+	if (!mtd)
+		return;
+
+	mod = (cxt->nextpage * record_size) % mtd->erasesize;
+	if (mod != 0) {
+		cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
+		if (cxt->nextpage >= cxt->oops_pages)
+			cxt->nextpage = 0;
+	}
+
+	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
+badblock:
+		pr_warn("bad block at %08lx\n",
+			cxt->nextpage * record_size);
+		i++;
+		cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
+		if (cxt->nextpage >= cxt->oops_pages)
+			cxt->nextpage = 0;
+		if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
+			pr_err("all blocks bad!\n");
+			return;
+		}
+	}
+
+	if (ret < 0) {
+		pr_err("mtd_block_isbad failed, aborting\n");
+		return;
+	}
+
+	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
+		ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
+
+	if (ret >= 0) {
+		pr_debug("ready %d, %d\n",
+			 cxt->nextpage, cxt->nextcount);
+		return;
+	}
+
+	if (ret == -EIO) {
+		ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
+		if (ret < 0 && ret != -EOPNOTSUPP) {
+			pr_err("block_markbad failed, aborting\n");
+			return;
+		}
+	}
+	goto badblock;
+}
+
+/* Scheduled work - when we can't proceed without erasing a block */
+static void mtdoops_workfunc_erase(struct work_struct *work)
+{
+	struct mtdoops_context *cxt =
+			container_of(work, struct mtdoops_context, work_erase);
+	mtdoops_erase(cxt);
+}
+
+static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)
+{
+	cxt->nextpage++;
+	if (cxt->nextpage >= cxt->oops_pages)
+		cxt->nextpage = 0;
+	cxt->nextcount++;
+	if (cxt->nextcount == 0xffffffff)
+		cxt->nextcount = 0;
+
+	if (page_is_used(cxt, cxt->nextpage)) {
+		pr_debug("not ready %d, %d (erase %s)\n",
+			 cxt->nextpage, cxt->nextcount,
+			 panic ? "immediately" : "scheduled");
+		if (panic) {
+			/* In case of panic, erase immediately */
+			mtdoops_erase(cxt);
+		} else {
+			/* Otherwise, schedule work to erase it "nicely" */
+			schedule_work(&cxt->work_erase);
+		}
+	} else {
+		pr_debug("ready %d, %d (no erase)\n",
+			 cxt->nextpage, cxt->nextcount);
+	}
+}
+
+static void mtdoops_write(struct mtdoops_context *cxt, int panic)
+{
+	struct mtd_info *mtd = cxt->mtd;
+	size_t retlen;
+	struct mtdoops_hdr *hdr;
+	int ret;
+
+	if (test_and_set_bit(0, &cxt->oops_buf_busy))
+		return;
+
+	/* Add mtdoops header to the buffer */
+	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
+	hdr->seq = cxt->nextcount;
+	hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;
+	hdr->timestamp = ktime_get_real();
+
+	if (panic) {
+		ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
+				      record_size, &retlen, cxt->oops_buf);
+		if (ret == -EOPNOTSUPP) {
+			pr_err("Cannot write from panic without panic_write\n");
+			goto out;
+		}
+	} else
+		ret = mtd_write(mtd, cxt->nextpage * record_size,
+				record_size, &retlen, cxt->oops_buf);
+
+	if (retlen != record_size || ret < 0)
+		pr_err("write failure at %ld (%td of %ld written), error %d\n",
+		       cxt->nextpage * record_size, retlen, record_size, ret);
+	mark_page_used(cxt, cxt->nextpage);
+	memset(cxt->oops_buf, 0xff, record_size);
+
+	mtdoops_inc_counter(cxt, panic);
+out:
+	clear_bit(0, &cxt->oops_buf_busy);
+}
+
+static void mtdoops_workfunc_write(struct work_struct *work)
+{
+	struct mtdoops_context *cxt =
+			container_of(work, struct mtdoops_context, work_write);
+
+	mtdoops_write(cxt, 0);
+}
+
+static void find_next_position(struct mtdoops_context *cxt)
+{
+	struct mtd_info *mtd = cxt->mtd;
+	struct mtdoops_hdr hdr;
+	int ret, page, maxpos = 0;
+	u32 maxcount = 0xffffffff;
+	size_t retlen;
+
+	for (page = 0; page < cxt->oops_pages; page++) {
+		if (mtd_block_isbad(mtd, page * record_size))
+			continue;
+		/* Assume the page is used */
+		mark_page_used(cxt, page);
+		ret = mtd_read(mtd, page * record_size, sizeof(hdr),
+			       &retlen, (u_char *)&hdr);
+		if (retlen != sizeof(hdr) ||
+				(ret < 0 && !mtd_is_bitflip(ret))) {
+			pr_err("read failure at %ld (%zu of %zu read), err %d\n",
+			       page * record_size, retlen, sizeof(hdr), ret);
+			continue;
+		}
+
+		if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
+			mark_page_unused(cxt, page);
+		if (hdr.seq == 0xffffffff ||
+		    (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&
+		     hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))
+			continue;
+		if (maxcount == 0xffffffff) {
+			maxcount = hdr.seq;
+			maxpos = page;
+		} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
+			maxcount = hdr.seq;
+			maxpos = page;
+		} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
+			maxcount = hdr.seq;
+			maxpos = page;
+		} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
+					&& maxcount > 0x80000000) {
+			maxcount = hdr.seq;
+			maxpos = page;
+		}
+	}
+	if (maxcount == 0xffffffff) {
+		cxt->nextpage = cxt->oops_pages - 1;
+		cxt->nextcount = 0;
+	}
+	else {
+		cxt->nextpage = maxpos;
+		cxt->nextcount = maxcount;
+	}
+
+	mtdoops_inc_counter(cxt, 0);
+}
+
+static void mtdoops_do_dump(struct kmsg_dumper *dumper,
+			    struct kmsg_dump_detail *detail)
+{
+	struct mtdoops_context *cxt = container_of(dumper,
+			struct mtdoops_context, dump);
+	struct kmsg_dump_iter iter;
+
+	/* Only dump oopses if dump_oops is set */
+	if (detail->reason == KMSG_DUMP_OOPS && !dump_oops)
+		return;
+
+	kmsg_dump_rewind(&iter);
+
+	if (test_and_set_bit(0, &cxt->oops_buf_busy))
+		return;
+	kmsg_dump_get_buffer(&iter, true,
+			     cxt->oops_buf + sizeof(struct mtdoops_hdr),
+			     record_size - sizeof(struct mtdoops_hdr), NULL);
+	clear_bit(0, &cxt->oops_buf_busy);
+
+	if (detail->reason != KMSG_DUMP_OOPS) {
+		/* Panics must be written immediately */
+		mtdoops_write(cxt, 1);
+	} else {
+		/* For other cases, schedule work to write it "nicely" */
+		schedule_work(&cxt->work_write);
+	}
+}
+
+static void mtdoops_notify_add(struct mtd_info *mtd)
+{
+	struct mtdoops_context *cxt = &oops_cxt;
+	u64 mtdoops_pages = div_u64(mtd->size, record_size);
+	int err;
+
+	if (!strcmp(mtd->name, mtddev))
+		cxt->mtd_index = mtd->index;
+
+	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
+		return;
+
+	if (mtd->size < mtd->erasesize * 2) {
+		pr_err("MTD partition %d not big enough for mtdoops\n",
+		       mtd->index);
+		return;
+	}
+	if (mtd->erasesize < record_size) {
+		pr_err("eraseblock size of MTD partition %d too small\n",
+		       mtd->index);
+		return;
+	}
+	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
+		pr_err("mtd%d is too large (limit is %d MiB)\n",
+		       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
+		return;
+	}
+
+	/* oops_page_used is a bit field */
+	cxt->oops_page_used =
+		vmalloc_array(DIV_ROUND_UP(mtdoops_pages, BITS_PER_LONG),
+			      sizeof(unsigned long));
+	if (!cxt->oops_page_used) {
+		pr_err("could not allocate page array\n");
+		return;
+	}
+
+	cxt->dump.max_reason = KMSG_DUMP_OOPS;
+	cxt->dump.dump = mtdoops_do_dump;
+	err = kmsg_dump_register(&cxt->dump);
+	if (err) {
+		pr_err("registering kmsg dumper failed, error %d\n", err);
+		vfree(cxt->oops_page_used);
+		cxt->oops_page_used = NULL;
+		return;
+	}
+
+	cxt->mtd = mtd;
+	cxt->oops_pages = (int)mtd->size / record_size;
+	find_next_position(cxt);
+	pr_info("Attached to MTD device %d\n", mtd->index);
+}
+
+static void mtdoops_notify_remove(struct mtd_info *mtd)
+{
+	struct mtdoops_context *cxt = &oops_cxt;
+
+	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
+		return;
+
+	if (kmsg_dump_unregister(&cxt->dump) < 0)
+		pr_warn("could not unregister kmsg_dumper\n");
+
+	cxt->mtd = NULL;
+	flush_work(&cxt->work_erase);
+	flush_work(&cxt->work_write);
+	vfree(cxt->oops_page_used);
+	cxt->oops_page_used = NULL;
+	cxt->oops_pages = 0;
+}
+
+
+static struct mtd_notifier mtdoops_notifier = {
+	.add	= mtdoops_notify_add,
+	.remove	= mtdoops_notify_remove,
+};
+
+static int __init mtdoops_init(void)
+{
+	struct mtdoops_context *cxt = &oops_cxt;
+	unsigned int mtd_index;
+
+	if (strlen(mtddev) == 0) {
+		pr_err("mtd device (mtddev=name/number) must be supplied\n");
+		return -EINVAL;
+	}
+	if ((record_size & 4095) != 0) {
+		pr_err("record_size must be a multiple of 4096\n");
+		return -EINVAL;
+	}
+	if (record_size < 4096) {
+		pr_err("record_size must be over 4096 bytes\n");
+		return -EINVAL;
+	}
+
+	/* Setup the MTD device to use */
+	cxt->mtd_index = -1;
+	if (kstrtouint(mtddev, 0, &mtd_index) == 0) {
+		cxt->mtd_index = mtd_index;
+	}
+
+	cxt->oops_buf = vmalloc(record_size);
+	if (!cxt->oops_buf)
+		return -ENOMEM;
+	memset(cxt->oops_buf, 0xff, record_size);
+	cxt->oops_buf_busy = 0;
+
+	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
+	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
+
+	register_mtd_user(&mtdoops_notifier);
+	return 0;
+}
+
+static void __exit mtdoops_exit(void)
+{
+	struct mtdoops_context *cxt = &oops_cxt;
+
+	unregister_mtd_user(&mtdoops_notifier);
+	vfree(cxt->oops_buf);
+	vfree(cxt->oops_page_used);
+}
+
+
+module_init(mtdoops_init);
+module_exit(mtdoops_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
+MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");