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, 257 insertions, 0 deletions

diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
new file mode 100644
index 000000000..887de505b
--- /dev/null
+++ b/drivers/scsi/scsicam.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * scsicam.c - SCSI CAM support functions, use for HDIO_GETGEO, etc.
+ *
+ * Copyright 1993, 1994 Drew Eckhardt
+ *      Visionary Computing 
+ *      (Unix and Linux consulting and custom programming)
+ *      drew@Colorado.EDU
+ *      +1 (303) 786-7975
+ *
+ * For more information, please consult the SCSI-CAM draft.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/pagemap.h>
+#include <linux/msdos_partition.h>
+#include <linux/unaligned.h>
+
+#include <scsi/scsicam.h>
+
+/**
+ * scsi_bios_ptable - Read PC partition table out of first sector of device.
+ * @dev: from this device
+ *
+ * Description: Reads the first sector from the device and returns %0x42 bytes
+ *              starting at offset %0x1be.
+ * Returns: partition table in kmalloc(GFP_KERNEL) memory, or NULL on error.
+ */
+unsigned char *scsi_bios_ptable(struct gendisk *dev)
+{
+	struct address_space *mapping = dev->part0->bd_mapping;
+	unsigned char *res = NULL;
+	struct folio *folio;
+
+	folio = read_mapping_folio(mapping, 0, NULL);
+	if (IS_ERR(folio))
+		return NULL;
+
+	res = kmemdup(folio_address(folio) + 0x1be, 66, GFP_KERNEL);
+	folio_put(folio);
+	return res;
+}
+EXPORT_SYMBOL(scsi_bios_ptable);
+
+/**
+ * scsi_partsize - Parse cylinders/heads/sectors from PC partition table
+ * @disk: gendisk of the disk to parse
+ * @capacity: size of the disk in sectors
+ * @geom: output in form of [hds, cylinders, sectors]
+ *
+ * Determine the BIOS mapping/geometry used to create the partition
+ * table, storing the results in @geom.
+ *
+ * Returns: %false on failure, %true on success.
+ */
+bool scsi_partsize(struct gendisk *disk, sector_t capacity, int geom[3])
+{
+	int cyl, ext_cyl, end_head, end_cyl, end_sector;
+	unsigned int logical_end, physical_end, ext_physical_end;
+	struct msdos_partition *p, *largest = NULL;
+	void *buf;
+	int ret = false;
+
+	buf = scsi_bios_ptable(disk);
+	if (!buf)
+		return false;
+
+	if (*(unsigned short *) (buf + 64) == 0xAA55) {
+		int largest_cyl = -1, i;
+
+		for (i = 0, p = buf; i < 4; i++, p++) {
+			if (!p->sys_ind)
+				continue;
+#ifdef DEBUG
+			printk("scsicam_bios_param : partition %d has system \n",
+			       i);
+#endif
+			cyl = p->cyl + ((p->sector & 0xc0) << 2);
+			if (cyl > largest_cyl) {
+				largest_cyl = cyl;
+				largest = p;
+			}
+		}
+	}
+	if (largest) {
+		end_cyl = largest->end_cyl + ((largest->end_sector & 0xc0) << 2);
+		end_head = largest->end_head;
+		end_sector = largest->end_sector & 0x3f;
+
+		if (end_head + 1 == 0 || end_sector == 0)
+			goto out_free_buf;
+
+#ifdef DEBUG
+		printk("scsicam_bios_param : end at h = %d, c = %d, s = %d\n",
+		       end_head, end_cyl, end_sector);
+#endif
+
+		physical_end = end_cyl * (end_head + 1) * end_sector +
+		    end_head * end_sector + end_sector;
+
+		/* This is the actual _sector_ number at the end */
+		logical_end = get_unaligned_le32(&largest->start_sect)
+		    + get_unaligned_le32(&largest->nr_sects);
+
+		/* This is for >1023 cylinders */
+		ext_cyl = (logical_end - (end_head * end_sector + end_sector))
+		    / (end_head + 1) / end_sector;
+		ext_physical_end = ext_cyl * (end_head + 1) * end_sector +
+		    end_head * end_sector + end_sector;
+
+#ifdef DEBUG
+		printk("scsicam_bios_param : logical_end=%d physical_end=%d ext_physical_end=%d ext_cyl=%d\n"
+		  ,logical_end, physical_end, ext_physical_end, ext_cyl);
+#endif
+
+		if (logical_end == physical_end ||
+		    (end_cyl == 1023 && ext_physical_end == logical_end)) {
+			geom[0] = end_head + 1;
+			geom[1] = end_sector;
+			geom[2] = (unsigned long)capacity /
+				((end_head + 1) * end_sector);
+			ret = true;
+			goto out_free_buf;
+		}
+#ifdef DEBUG
+		printk("scsicam_bios_param : logical (%u) != physical (%u)\n",
+		       logical_end, physical_end);
+#endif
+	}
+
+out_free_buf:
+	kfree(buf);
+	return ret;
+}
+EXPORT_SYMBOL(scsi_partsize);
+
+/*
+ * Function : static int setsize(unsigned long capacity,unsigned int *cyls,
+ *      unsigned int *hds, unsigned int *secs);
+ *
+ * Purpose : to determine a near-optimal int 0x13 mapping for a
+ *      SCSI disk in terms of lost space of size capacity, storing
+ *      the results in *cyls, *hds, and *secs.
+ *
+ * Returns : -1 on failure, 0 on success.
+ *
+ * Extracted from
+ *
+ * WORKING                                                    X3T9.2
+ * DRAFT                                                        792D
+ * see http://www.t10.org/ftp/t10/drafts/cam/cam-r12b.pdf
+ *
+ *                                                        Revision 6
+ *                                                         10-MAR-94
+ * Information technology -
+ * SCSI-2 Common access method
+ * transport and SCSI interface module
+ * 
+ * ANNEX A :
+ *
+ * setsize() converts a read capacity value to int 13h
+ * head-cylinder-sector requirements. It minimizes the value for
+ * number of heads and maximizes the number of cylinders. This
+ * will support rather large disks before the number of heads
+ * will not fit in 4 bits (or 6 bits). This algorithm also
+ * minimizes the number of sectors that will be unused at the end
+ * of the disk while allowing for very large disks to be
+ * accommodated. This algorithm does not use physical geometry. 
+ */
+
+static int setsize(unsigned long capacity, unsigned int *cyls, unsigned int *hds,
+		   unsigned int *secs)
+{
+	unsigned int rv = 0;
+	unsigned long heads, sectors, cylinders, temp;
+
+	cylinders = 1024L;	/* Set number of cylinders to max */
+	sectors = 62L;		/* Maximize sectors per track */
+
+	temp = cylinders * sectors;	/* Compute divisor for heads */
+	heads = capacity / temp;	/* Compute value for number of heads */
+	if (capacity % temp) {	/* If no remainder, done! */
+		heads++;	/* Else, increment number of heads */
+		temp = cylinders * heads;	/* Compute divisor for sectors */
+		sectors = capacity / temp;	/* Compute value for sectors per
+						   track */
+		if (capacity % temp) {	/* If no remainder, done! */
+			sectors++;	/* Else, increment number of sectors */
+			temp = heads * sectors;		/* Compute divisor for cylinders */
+			cylinders = capacity / temp;	/* Compute number of cylinders */
+		}
+	}
+	if (cylinders == 0)
+		rv = (unsigned) -1;	/* Give error if 0 cylinders */
+
+	*cyls = (unsigned int) cylinders;	/* Stuff return values */
+	*secs = (unsigned int) sectors;
+	*hds = (unsigned int) heads;
+	return (rv);
+}
+
+/**
+ * scsicam_bios_param - Determine geometry of a disk in cylinders/heads/sectors.
+ * @disk: which device
+ * @capacity: size of the disk in sectors
+ * @ip: return value: ip[0]=heads, ip[1]=sectors, ip[2]=cylinders
+ *
+ * Description : determine the BIOS mapping/geometry used for a drive in a
+ *      SCSI-CAM system, storing the results in ip as required
+ *      by the HDIO_GETGEO ioctl().
+ *
+ * Returns : -1 on failure, 0 on success.
+ */
+int scsicam_bios_param(struct gendisk *disk, sector_t capacity, int *ip)
+{
+	u64 capacity64 = capacity;	/* Suppress gcc warning */
+	int ret = 0;
+
+	/* try to infer mapping from partition table */
+	if (scsi_partsize(disk, capacity, ip))
+		return 0;
+
+	if (capacity64 < (1ULL << 32)) {
+		/*
+		 * Pick some standard mapping with at most 1024 cylinders, and
+		 * at most 62 sectors per track - this works up to 7905 MB.
+		 */
+		ret = setsize((unsigned long)capacity, (unsigned int *)ip + 2,
+		       (unsigned int *)ip + 0, (unsigned int *)ip + 1);
+	}
+
+	/*
+	 * If something went wrong, then apparently we have to return a geometry
+	 * with more than 1024 cylinders.
+	 */
+	if (ret || ip[0] > 255 || ip[1] > 63) {
+		if ((capacity >> 11) > 65534) {
+			ip[0] = 255;
+			ip[1] = 63;
+		} else {
+			ip[0] = 64;
+			ip[1] = 32;
+		}
+
+		if (capacity > 65535*63*255)
+			ip[2] = 65535;
+		else
+			ip[2] = (unsigned long)capacity / (ip[0] * ip[1]);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(scsicam_bios_param);