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

5 files changed, 185 insertions, 0 deletions

diff --git a/arch/arm/boot/bootp/Makefile b/arch/arm/boot/bootp/Makefile
new file mode 100644
index 000000000..f3443f7d7
--- /dev/null
+++ b/arch/arm/boot/bootp/Makefile
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# linux/arch/arm/boot/bootp/Makefile
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+#
+
+ifdef PHYS_OFFSET
+add_hex = $(shell printf 0x%x $$(( $(1) + $(2) )) )
+
+# If PHYS_OFFSET is set, INITRD_PHYS and PARAMS_PHYS can be derived,
+# otherwise they must be passed on the command line.
+#
+# Note: the following conditions must always be true:
+#   PARAMS_PHYS must be within 4MB of ZRELADDR
+#   INITRD_PHYS must be in RAM
+
+PARAMS_PHYS := $(call add_hex, $(PHYS_OFFSET), 0x100)
+
+# guess an initrd location if possible
+initrd_offset-$(CONFIG_ARCH_FOOTBRIDGE)	+= 0x00800000
+initrd_offset-$(CONFIG_ARCH_SA1100)	+= 0x00800000
+initrd_offset-$(CONFIG_ARCH_RPC)	+= 0x08000000
+INITRD_OFFSET := $(initrd_offset-y)
+ifdef INITRD_OFFSET
+INITRD_PHYS := $(call add_hex, $(PHYS_OFFSET), $(INITRD_OFFSET))
+endif
+
+endif
+
+PHONY += initrd
+initrd:
+	@test "$(PARAMS_PHYS)" != "" || \
+	(echo bootpImage: You must specify PHYS_OFFSET of PARAMS_PHYS ; exit -1)
+	@test "$(INITRD_PHYS)" != "" || \
+	(echo bootpImage: You must specify INITRD_OFFSET or INITRD_PHYS ; exit -1)
+	@test "$(INITRD)" != "" || \
+	(echo bootpImage: You must specify INITRD; exit -1)
+
+LDFLAGS_bootp	:= --no-undefined -X \
+		 --defsym initrd_phys=$(INITRD_PHYS) \
+		 --defsym params_phys=$(PARAMS_PHYS) -T
+AFLAGS_initrd.o :=-DINITRD=\"$(INITRD)\"
+
+targets	:= bootp init.o kernel.o initrd.o
+
+# Note that bootp.lds picks up kernel.o and initrd.o
+$(obj)/bootp:	$(src)/bootp.lds $(addprefix $(obj)/,init.o kernel.o initrd.o) FORCE
+	$(call if_changed,ld)
+
+# kernel.o and initrd.o includes a binary image using
+# .incbin, a dependency which is not tracked automatically
+
+$(obj)/kernel.o: arch/arm/boot/zImage FORCE
+
+$(obj)/initrd.o: initrd $(INITRD) FORCE
+
+PHONY += $(INITRD)
diff --git a/arch/arm/boot/bootp/bootp.lds b/arch/arm/boot/bootp/bootp.lds
new file mode 100644
index 000000000..160128186
--- /dev/null
+++ b/arch/arm/boot/bootp/bootp.lds
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/arch/arm/boot/bootp/bootp.lds
+ *
+ *  Copyright (C) 2000-2002 Russell King
+ */
+OUTPUT_ARCH(arm)
+ENTRY(_start)
+SECTIONS
+{
+  . = 0;
+  .text : {
+   _stext = .;
+   *(.start)
+   *(.text)
+   initrd_size = initrd_end - initrd_start;
+   _etext = .;
+  }
+
+  .stab 0 : { *(.stab) }
+  .stabstr 0 : { *(.stabstr) }
+  .stab.excl 0 : { *(.stab.excl) }
+  .stab.exclstr 0 : { *(.stab.exclstr) }
+  .stab.index 0 : { *(.stab.index) }
+  .stab.indexstr 0 : { *(.stab.indexstr) }
+  .comment 0 : { *(.comment) }
+}
diff --git a/arch/arm/boot/bootp/init.S b/arch/arm/boot/bootp/init.S
new file mode 100644
index 000000000..b562da2f7
--- /dev/null
+++ b/arch/arm/boot/bootp/init.S
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/arch/arm/boot/bootp/init.S
+ *
+ *  Copyright (C) 2000-2003 Russell King.
+ *
+ *  "Header" file for splitting kernel + initrd.  Note that we pass
+ *  r0 through to r3 straight through.
+ *
+ *  This demonstrates how to append code to the start of the kernel
+ *  zImage, and boot the kernel without copying it around.  This
+ *  example would be simpler; if we didn't have an object of unknown
+ *  size immediately following the kernel, we could build this into
+ *  a binary blob, and concatenate the zImage using the cat command.
+ */
+		.section .start, "ax"
+		.type	_start, #function
+		.globl	_start
+
+_start:		add	lr, pc, #-0x8		@ lr = current load addr
+		adr	r13, data
+		ldmia	r13!, {r4-r6}		@ r5 = dest, r6 = length
+		add	r4, r4, lr		@ r4 = initrd_start + load addr
+		bl	move			@ move the initrd
+
+/*
+ * Setup the initrd parameters to pass to the kernel.  This can only be
+ * passed in via the tagged list.
+ */
+		ldmia	r13, {r5-r9}		@ get size and addr of initrd
+						@ r5 = ATAG_CORE
+						@ r6 = ATAG_INITRD2
+						@ r7 = initrd start
+						@ r8 = initrd end
+						@ r9 = param_struct address
+
+		ldr	r10, [r9, #4]		@ get first tag
+		teq	r10, r5			@ is it ATAG_CORE?
+/*
+ * If we didn't find a valid tag list, create a dummy ATAG_CORE entry.
+ */
+		movne	r10, #0			@ terminator
+		movne	r4, #2			@ Size of this entry (2 words)
+		stmiane	r9, {r4, r5, r10}	@ Size, ATAG_CORE, terminator
+
+/*
+ * find the end of the tag list, and then add an INITRD tag on the end.
+ * If there is already an INITRD tag, then we ignore it; the last INITRD
+ * tag takes precedence.
+ */
+taglist:	ldr	r10, [r9, #0]		@ tag length
+		teq	r10, #0			@ last tag (zero length)?
+		addne	r9, r9, r10, lsl #2
+		bne	taglist
+
+		mov	r5, #4			@ Size of initrd tag (4 words)
+		stmia	r9, {r5, r6, r7, r8, r10}
+		b	kernel_start		@ call kernel
+
+/*
+ * Move the block of memory length r6 from address r4 to address r5
+ */
+move:		ldmia	r4!, {r7 - r10}		@ move 32-bytes at a time
+		stmia	r5!, {r7 - r10}
+		ldmia	r4!, {r7 - r10}
+		stmia	r5!, {r7 - r10}
+		subs	r6, r6, #8 * 4
+		bcs	move
+		mov	pc, lr
+
+		.size	_start, . - _start
+
+		.align
+
+		.type	data,#object
+data:		.word	initrd_start		@ source initrd address
+		.word	initrd_phys		@ destination initrd address
+		.word	initrd_size		@ initrd size
+
+		.word	0x54410001		@ r5 = ATAG_CORE
+		.word	0x54420005		@ r6 = ATAG_INITRD2
+		.word	initrd_phys		@ r7
+		.word	initrd_size		@ r8
+		.word	params_phys		@ r9
+		.size	data, . - data
diff --git a/arch/arm/boot/bootp/initrd.S b/arch/arm/boot/bootp/initrd.S
new file mode 100644
index 000000000..dd3d04971
--- /dev/null
+++ b/arch/arm/boot/bootp/initrd.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+	.type	initrd_start,#object
+	.globl	initrd_start
+initrd_start:
+	.incbin	INITRD
+	.globl	initrd_end
+initrd_end:
diff --git a/arch/arm/boot/bootp/kernel.S b/arch/arm/boot/bootp/kernel.S
new file mode 100644
index 000000000..dc6236c17
--- /dev/null
+++ b/arch/arm/boot/bootp/kernel.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+	.globl	kernel_start
+kernel_start:
+	.incbin	"arch/arm/boot/zImage"
+	.globl	kernel_end
+kernel_end:
+	.align	2