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, 256 insertions, 0 deletions

diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
new file mode 100644
index 000000000..624fab589
--- /dev/null
+++ b/include/crypto/scatterwalk.h
@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Cryptographic scatter and gather helpers.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
+ * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_SCATTERWALK_H
+#define _CRYPTO_SCATTERWALK_H
+
+#include <crypto/algapi.h>
+
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+
+static inline void scatterwalk_crypto_chain(struct scatterlist *head,
+					    struct scatterlist *sg, int num)
+{
+	if (sg)
+		sg_chain(head, num, sg);
+	else
+		sg_mark_end(head);
+}
+
+static inline void scatterwalk_start(struct scatter_walk *walk,
+				     struct scatterlist *sg)
+{
+	walk->sg = sg;
+	walk->offset = sg->offset;
+}
+
+/*
+ * This is equivalent to scatterwalk_start(walk, sg) followed by
+ * scatterwalk_skip(walk, pos).
+ */
+static inline void scatterwalk_start_at_pos(struct scatter_walk *walk,
+					    struct scatterlist *sg,
+					    unsigned int pos)
+{
+	while (pos > sg->length) {
+		pos -= sg->length;
+		sg = sg_next(sg);
+	}
+	walk->sg = sg;
+	walk->offset = sg->offset + pos;
+}
+
+static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
+					     unsigned int nbytes)
+{
+	unsigned int len_this_sg;
+	unsigned int limit;
+
+	if (walk->offset >= walk->sg->offset + walk->sg->length)
+		scatterwalk_start(walk, sg_next(walk->sg));
+	len_this_sg = walk->sg->offset + walk->sg->length - walk->offset;
+
+	/*
+	 * HIGHMEM case: the page may have to be mapped into memory.  To avoid
+	 * the complexity of having to map multiple pages at once per sg entry,
+	 * clamp the returned length to not cross a page boundary.
+	 *
+	 * !HIGHMEM case: no mapping is needed; all pages of the sg entry are
+	 * already mapped contiguously in the kernel's direct map.  For improved
+	 * performance, allow the walker to return data segments that cross a
+	 * page boundary.  Do still cap the length to PAGE_SIZE, since some
+	 * users rely on that to avoid disabling preemption for too long when
+	 * using SIMD.  It's also needed for when skcipher_walk uses a bounce
+	 * page due to the data not being aligned to the algorithm's alignmask.
+	 */
+	if (IS_ENABLED(CONFIG_HIGHMEM))
+		limit = PAGE_SIZE - offset_in_page(walk->offset);
+	else
+		limit = PAGE_SIZE;
+
+	return min3(nbytes, len_this_sg, limit);
+}
+
+/*
+ * Create a scatterlist that represents the remaining data in a walk.  Uses
+ * chaining to reference the original scatterlist, so this uses at most two
+ * entries in @sg_out regardless of the number of entries in the original list.
+ * Assumes that sg_init_table() was already done.
+ */
+static inline void scatterwalk_get_sglist(struct scatter_walk *walk,
+					  struct scatterlist sg_out[2])
+{
+	if (walk->offset >= walk->sg->offset + walk->sg->length)
+		scatterwalk_start(walk, sg_next(walk->sg));
+	sg_set_page(sg_out, sg_page(walk->sg),
+		    walk->sg->offset + walk->sg->length - walk->offset,
+		    walk->offset);
+	scatterwalk_crypto_chain(sg_out, sg_next(walk->sg), 2);
+}
+
+static inline void scatterwalk_map(struct scatter_walk *walk)
+{
+	struct page *base_page = sg_page(walk->sg);
+	unsigned int offset = walk->offset;
+	void *addr;
+
+	if (IS_ENABLED(CONFIG_HIGHMEM)) {
+		struct page *page;
+
+		page = base_page + (offset >> PAGE_SHIFT);
+		offset = offset_in_page(offset);
+		addr = kmap_local_page(page) + offset;
+	} else {
+		/*
+		 * When !HIGHMEM we allow the walker to return segments that
+		 * span a page boundary; see scatterwalk_clamp().  To make it
+		 * clear that in this case we're working in the linear buffer of
+		 * the whole sg entry in the kernel's direct map rather than
+		 * within the mapped buffer of a single page, compute the
+		 * address as an offset from the page_address() of the first
+		 * page of the sg entry.  Either way the result is the address
+		 * in the direct map, but this makes it clearer what is really
+		 * going on.
+		 */
+		addr = page_address(base_page) + offset;
+	}
+
+	walk->__addr = addr;
+}
+
+/**
+ * scatterwalk_next() - Get the next data buffer in a scatterlist walk
+ * @walk: the scatter_walk
+ * @total: the total number of bytes remaining, > 0
+ *
+ * A virtual address for the next segment of data from the scatterlist will
+ * be placed into @walk->addr.  The caller must call scatterwalk_done_src()
+ * or scatterwalk_done_dst() when it is done using this virtual address.
+ *
+ * Returns: the next number of bytes available, <= @total
+ */
+static inline unsigned int scatterwalk_next(struct scatter_walk *walk,
+					    unsigned int total)
+{
+	unsigned int nbytes = scatterwalk_clamp(walk, total);
+
+	scatterwalk_map(walk);
+	return nbytes;
+}
+
+static inline void scatterwalk_unmap(struct scatter_walk *walk)
+{
+	if (IS_ENABLED(CONFIG_HIGHMEM))
+		kunmap_local(walk->__addr);
+}
+
+static inline void scatterwalk_advance(struct scatter_walk *walk,
+				       unsigned int nbytes)
+{
+	walk->offset += nbytes;
+}
+
+/**
+ * scatterwalk_done_src() - Finish one step of a walk of source scatterlist
+ * @walk: the scatter_walk
+ * @nbytes: the number of bytes processed this step, less than or equal to the
+ *	    number of bytes that scatterwalk_next() returned.
+ *
+ * Use this if the mapped address was not written to, i.e. it is source data.
+ */
+static inline void scatterwalk_done_src(struct scatter_walk *walk,
+					unsigned int nbytes)
+{
+	scatterwalk_unmap(walk);
+	scatterwalk_advance(walk, nbytes);
+}
+
+/*
+ * Flush the dcache of any pages that overlap the region
+ * [offset, offset + nbytes) relative to base_page.
+ *
+ * This should be called only when ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, to ensure
+ * that all relevant code (including the call to sg_page() in the caller, if
+ * applicable) gets fully optimized out when !ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE.
+ */
+static inline void __scatterwalk_flush_dcache_pages(struct page *base_page,
+						    unsigned int offset,
+						    unsigned int nbytes)
+{
+	unsigned int num_pages;
+
+	base_page += offset / PAGE_SIZE;
+	offset %= PAGE_SIZE;
+
+	/*
+	 * This is an overflow-safe version of
+	 * num_pages = DIV_ROUND_UP(offset + nbytes, PAGE_SIZE).
+	 */
+	num_pages = nbytes / PAGE_SIZE;
+	num_pages += DIV_ROUND_UP(offset + (nbytes % PAGE_SIZE), PAGE_SIZE);
+
+	for (unsigned int i = 0; i < num_pages; i++)
+		flush_dcache_page(base_page + i);
+}
+
+/**
+ * scatterwalk_done_dst() - Finish one step of a walk of destination scatterlist
+ * @walk: the scatter_walk
+ * @nbytes: the number of bytes processed this step, less than or equal to the
+ *	    number of bytes that scatterwalk_next() returned.
+ *
+ * Use this if the mapped address may have been written to, i.e. it is
+ * destination data.
+ */
+static inline void scatterwalk_done_dst(struct scatter_walk *walk,
+					unsigned int nbytes)
+{
+	scatterwalk_unmap(walk);
+	if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE)
+		__scatterwalk_flush_dcache_pages(sg_page(walk->sg),
+						 walk->offset, nbytes);
+	scatterwalk_advance(walk, nbytes);
+}
+
+void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes);
+
+void memcpy_from_scatterwalk(void *buf, struct scatter_walk *walk,
+			     unsigned int nbytes);
+
+void memcpy_to_scatterwalk(struct scatter_walk *walk, const void *buf,
+			   unsigned int nbytes);
+
+void memcpy_from_sglist(void *buf, struct scatterlist *sg,
+			unsigned int start, unsigned int nbytes);
+
+void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
+		      const void *buf, unsigned int nbytes);
+
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes);
+
+/* In new code, please use memcpy_{from,to}_sglist() directly instead. */
+static inline void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
+					    unsigned int start,
+					    unsigned int nbytes, int out)
+{
+	if (out)
+		memcpy_to_sglist(sg, start, buf, nbytes);
+	else
+		memcpy_from_sglist(buf, sg, start, nbytes);
+}
+
+struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
+				     struct scatterlist *src,
+				     unsigned int len);
+
+#endif  /* _CRYPTO_SCATTERWALK_H */