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, 413 insertions, 0 deletions

diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
new file mode 100644
index 000000000..66270904f
--- /dev/null
+++ b/arch/arm/mm/flush.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/mm/flush.c
+ *
+ *  Copyright (C) 1995-2002 Russell King
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cachetype.h>
+#include <asm/highmem.h>
+#include <asm/smp_plat.h>
+#include <asm/tlbflush.h>
+#include <linux/hugetlb.h>
+
+#include "mm.h"
+
+#ifdef CONFIG_ARM_HEAVY_MB
+void (*soc_mb)(void);
+
+void arm_heavy_mb(void)
+{
+#ifdef CONFIG_OUTER_CACHE_SYNC
+	if (outer_cache.sync)
+		outer_cache.sync();
+#endif
+	if (soc_mb)
+		soc_mb();
+}
+EXPORT_SYMBOL(arm_heavy_mb);
+#endif
+
+#ifdef CONFIG_CPU_CACHE_VIPT
+
+static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
+{
+	unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
+	const int zero = 0;
+
+	set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL));
+
+	asm(	"mcrr	p15, 0, %1, %0, c14\n"
+	"	mcr	p15, 0, %2, c7, c10, 4"
+	    :
+	    : "r" (to), "r" (to + PAGE_SIZE - 1), "r" (zero)
+	    : "cc");
+}
+
+static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
+{
+	unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
+	unsigned long offset = vaddr & (PAGE_SIZE - 1);
+	unsigned long to;
+
+	set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL));
+	to = va + offset;
+	flush_icache_range(to, to + len);
+}
+
+void flush_cache_mm(struct mm_struct *mm)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_mm(mm);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4"
+		    :
+		    : "r" (0)
+		    : "cc");
+	}
+}
+
+void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_range(vma, start, end);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4"
+		    :
+		    : "r" (0)
+		    : "cc");
+	}
+
+	if (vma->vm_flags & VM_EXEC)
+		__flush_icache_all();
+}
+
+void flush_cache_pages(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn, unsigned int nr)
+{
+	if (cache_is_vivt()) {
+		vivt_flush_cache_pages(vma, user_addr, pfn, nr);
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		flush_pfn_alias(pfn, user_addr);
+		__flush_icache_all();
+	}
+
+	if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
+		__flush_icache_all();
+}
+
+#else
+#define flush_pfn_alias(pfn,vaddr)		do { } while (0)
+#define flush_icache_alias(pfn,vaddr,len)	do { } while (0)
+#endif
+
+#define FLAG_PA_IS_EXEC 1
+#define FLAG_PA_CORE_IN_MM 2
+
+static void flush_ptrace_access_other(void *args)
+{
+	__flush_icache_all();
+}
+
+static inline
+void __flush_ptrace_access(struct page *page, unsigned long uaddr, void *kaddr,
+			   unsigned long len, unsigned int flags)
+{
+	if (cache_is_vivt()) {
+		if (flags & FLAG_PA_CORE_IN_MM) {
+			unsigned long addr = (unsigned long)kaddr;
+			__cpuc_coherent_kern_range(addr, addr + len);
+		}
+		return;
+	}
+
+	if (cache_is_vipt_aliasing()) {
+		flush_pfn_alias(page_to_pfn(page), uaddr);
+		__flush_icache_all();
+		return;
+	}
+
+	/* VIPT non-aliasing D-cache */
+	if (flags & FLAG_PA_IS_EXEC) {
+		unsigned long addr = (unsigned long)kaddr;
+		if (icache_is_vipt_aliasing())
+			flush_icache_alias(page_to_pfn(page), uaddr, len);
+		else
+			__cpuc_coherent_kern_range(addr, addr + len);
+		if (cache_ops_need_broadcast())
+			smp_call_function(flush_ptrace_access_other,
+					  NULL, 1);
+	}
+}
+
+static
+void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
+			 unsigned long uaddr, void *kaddr, unsigned long len)
+{
+	unsigned int flags = 0;
+	if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm)))
+		flags |= FLAG_PA_CORE_IN_MM;
+	if (vma->vm_flags & VM_EXEC)
+		flags |= FLAG_PA_IS_EXEC;
+	__flush_ptrace_access(page, uaddr, kaddr, len, flags);
+}
+
+void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
+			     void *kaddr, unsigned long len)
+{
+	unsigned int flags = FLAG_PA_CORE_IN_MM|FLAG_PA_IS_EXEC;
+
+	__flush_ptrace_access(page, uaddr, kaddr, len, flags);
+}
+
+/*
+ * Copy user data from/to a page which is mapped into a different
+ * processes address space.  Really, we want to allow our "user
+ * space" model to handle this.
+ *
+ * Note that this code needs to run on the current CPU.
+ */
+void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
+		       unsigned long uaddr, void *dst, const void *src,
+		       unsigned long len)
+{
+#ifdef CONFIG_SMP
+	preempt_disable();
+#endif
+	memcpy(dst, src, len);
+	flush_ptrace_access(vma, page, uaddr, dst, len);
+#ifdef CONFIG_SMP
+	preempt_enable();
+#endif
+}
+
+void __flush_dcache_folio(struct address_space *mapping, struct folio *folio)
+{
+	/*
+	 * Writeback any data associated with the kernel mapping of this
+	 * page.  This ensures that data in the physical page is mutually
+	 * coherent with the kernels mapping.
+	 */
+	if (!folio_test_highmem(folio)) {
+		__cpuc_flush_dcache_area(folio_address(folio),
+					folio_size(folio));
+	} else {
+		unsigned long i;
+		if (cache_is_vipt_nonaliasing()) {
+			for (i = 0; i < folio_nr_pages(folio); i++) {
+				void *addr = kmap_local_folio(folio,
+								i * PAGE_SIZE);
+				__cpuc_flush_dcache_area(addr, PAGE_SIZE);
+				kunmap_local(addr);
+			}
+		} else {
+			for (i = 0; i < folio_nr_pages(folio); i++) {
+				void *addr = kmap_high_get(folio_page(folio, i));
+				if (addr) {
+					__cpuc_flush_dcache_area(addr, PAGE_SIZE);
+					kunmap_high(folio_page(folio, i));
+				}
+			}
+		}
+	}
+
+	/*
+	 * If this is a page cache folio, and we have an aliasing VIPT cache,
+	 * we only need to do one flush - which would be at the relevant
+	 * userspace colour, which is congruent with folio->index.
+	 */
+	if (mapping && cache_is_vipt_aliasing())
+		flush_pfn_alias(folio_pfn(folio), folio_pos(folio));
+}
+
+static void __flush_dcache_aliases(struct address_space *mapping, struct folio *folio)
+{
+	struct mm_struct *mm = current->active_mm;
+	struct vm_area_struct *vma;
+	pgoff_t pgoff, pgoff_end;
+
+	/*
+	 * There are possible user space mappings of this page:
+	 * - VIVT cache: we need to also write back and invalidate all user
+	 *   data in the current VM view associated with this page.
+	 * - aliasing VIPT: we only need to find one mapping of this page.
+	 */
+	pgoff = folio->index;
+	pgoff_end = pgoff + folio_nr_pages(folio) - 1;
+
+	flush_dcache_mmap_lock(mapping);
+	mapping_rmap_tree_foreach(vma, mapping, pgoff, pgoff_end) {
+		unsigned long start, offset, pfn;
+		unsigned int nr;
+
+		/*
+		 * If this VMA is not in our MM, we can ignore it.
+		 */
+		if (vma->vm_mm != mm)
+			continue;
+		if (!(vma->vm_flags & VM_MAYSHARE))
+			continue;
+
+		start = vma->vm_start;
+		pfn = folio_pfn(folio);
+		nr = folio_nr_pages(folio);
+		offset = pgoff - vma->vm_pgoff;
+		if (offset > -nr) {
+			pfn -= offset;
+			nr += offset;
+		} else {
+			start += offset * PAGE_SIZE;
+		}
+		if (start + nr * PAGE_SIZE > vma->vm_end)
+			nr = (vma->vm_end - start) / PAGE_SIZE;
+
+		flush_cache_pages(vma, start, pfn, nr);
+	}
+	flush_dcache_mmap_unlock(mapping);
+}
+
+#if __LINUX_ARM_ARCH__ >= 6
+void __sync_icache_dcache(pte_t pteval)
+{
+	unsigned long pfn;
+	struct folio *folio;
+	struct address_space *mapping;
+
+	if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
+		/* only flush non-aliasing VIPT caches for exec mappings */
+		return;
+	pfn = pte_pfn(pteval);
+	if (!pfn_valid(pfn))
+		return;
+
+	folio = page_folio(pfn_to_page(pfn));
+	if (folio_test_reserved(folio))
+		return;
+
+	if (cache_is_vipt_aliasing())
+		mapping = folio_flush_mapping(folio);
+	else
+		mapping = NULL;
+
+	if (!test_bit(PG_dcache_clean, &folio->flags.f)) {
+		__flush_dcache_folio(mapping, folio);
+		set_bit(PG_dcache_clean, &folio->flags.f);
+	}
+
+	if (pte_exec(pteval))
+		__flush_icache_all();
+}
+#endif
+
+/*
+ * Ensure cache coherency between kernel mapping and userspace mapping
+ * of this page.
+ *
+ * We have three cases to consider:
+ *  - VIPT non-aliasing cache: fully coherent so nothing required.
+ *  - VIVT: fully aliasing, so we need to handle every alias in our
+ *          current VM view.
+ *  - VIPT aliasing: need to handle one alias in our current VM view.
+ *
+ * If we need to handle aliasing:
+ *  If the page only exists in the page cache and there are no user
+ *  space mappings, we can be lazy and remember that we may have dirty
+ *  kernel cache lines for later.  Otherwise, we assume we have
+ *  aliasing mappings.
+ *
+ * Note that we disable the lazy flush for SMP configurations where
+ * the cache maintenance operations are not automatically broadcasted.
+ */
+void flush_dcache_folio(struct folio *folio)
+{
+	struct address_space *mapping;
+
+	/*
+	 * The zero page is never written to, so never has any dirty
+	 * cache lines, and therefore never needs to be flushed.
+	 */
+	if (is_zero_pfn(folio_pfn(folio)))
+		return;
+
+	if (!cache_ops_need_broadcast() && cache_is_vipt_nonaliasing()) {
+		if (test_bit(PG_dcache_clean, &folio->flags.f))
+			clear_bit(PG_dcache_clean, &folio->flags.f);
+		return;
+	}
+
+	mapping = folio_flush_mapping(folio);
+
+	if (!cache_ops_need_broadcast() &&
+	    mapping && !folio_mapped(folio))
+		clear_bit(PG_dcache_clean, &folio->flags.f);
+	else {
+		__flush_dcache_folio(mapping, folio);
+		if (mapping && cache_is_vivt())
+			__flush_dcache_aliases(mapping, folio);
+		else if (mapping)
+			__flush_icache_all();
+		set_bit(PG_dcache_clean, &folio->flags.f);
+	}
+}
+EXPORT_SYMBOL(flush_dcache_folio);
+
+void flush_dcache_page(struct page *page)
+{
+	flush_dcache_folio(page_folio(page));
+}
+EXPORT_SYMBOL(flush_dcache_page);
+/*
+ * Flush an anonymous page so that users of get_user_pages()
+ * can safely access the data.  The expected sequence is:
+ *
+ *  get_user_pages()
+ *    -> flush_anon_page
+ *  memcpy() to/from page
+ *  if written to page, flush_dcache_page()
+ */
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr);
+void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+{
+	unsigned long pfn;
+
+	/* VIPT non-aliasing caches need do nothing */
+	if (cache_is_vipt_nonaliasing())
+		return;
+
+	/*
+	 * Write back and invalidate userspace mapping.
+	 */
+	pfn = page_to_pfn(page);
+	if (cache_is_vivt()) {
+		flush_cache_page(vma, vmaddr, pfn);
+	} else {
+		/*
+		 * For aliasing VIPT, we can flush an alias of the
+		 * userspace address only.
+		 */
+		flush_pfn_alias(pfn, vmaddr);
+		__flush_icache_all();
+	}
+
+	/*
+	 * Invalidate kernel mapping.  No data should be contained
+	 * in this mapping of the page.  FIXME: this is overkill
+	 * since we actually ask for a write-back and invalidate.
+	 */
+	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+}