5.4-stable patches

added patches:
	xarray-fix-xas_create_range-when-multi-order-entry-present.patch

diff --git a/queue-5.4/series b/queue-5.4/series
index 79026d7828793e478b923a791baa17728c9bb2e7..491fbf2e20eb9b7162624783f6e0d19675eba86b 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -337,3 +337,4 @@ ubifs-add-missing-iput-if-do_tmpfile-failed-in-rename-whiteout.patch
 ubifs-setflags-make-dirtied_ino_d-8-bytes-aligned.patch
 ubifs-fix-read-out-of-bounds-in-ubifs_wbuf_write_nolock.patch
 ubifs-rename_whiteout-correct-old_dir-size-computing.patch
+xarray-fix-xas_create_range-when-multi-order-entry-present.patch

diff --git a/queue-5.4/xarray-fix-xas_create_range-when-multi-order-entry-present.patch b/queue-5.4/xarray-fix-xas_create_range-when-multi-order-entry-present.patch
new file mode 100644 (file)
index 0000000..3bdbcb1
--- /dev/null
+++ b/queue-5.4/xarray-fix-xas_create_range-when-multi-order-entry-present.patch
@@ -0,0 +1,85 @@
+From 3e3c658055c002900982513e289398a1aad4a488 Mon Sep 17 00:00:00 2001
+From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
+Date: Mon, 28 Mar 2022 19:25:11 -0400
+Subject: XArray: Fix xas_create_range() when multi-order entry present
+
+From: Matthew Wilcox (Oracle) <willy@infradead.org>
+
+commit 3e3c658055c002900982513e289398a1aad4a488 upstream.
+
+If there is already an entry present that is of order >= XA_CHUNK_SHIFT
+when we call xas_create_range(), xas_create_range() will misinterpret
+that entry as a node and dereference xa_node->parent, generally leading
+to a crash that looks something like this:
+
+general protection fault, probably for non-canonical address 0xdffffc0000000001:
+0000 [#1] PREEMPT SMP KASAN
+KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
+CPU: 0 PID: 32 Comm: khugepaged Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0
+RIP: 0010:xa_parent_locked include/linux/xarray.h:1207 [inline]
+RIP: 0010:xas_create_range+0x2d9/0x6e0 lib/xarray.c:725
+
+It's deterministically reproducable once you know what the problem is,
+but producing it in a live kernel requires khugepaged to hit a race.
+While the problem has been present since xas_create_range() was
+introduced, I'm not aware of a way to hit it before the page cache was
+converted to use multi-index entries.
+
+Fixes: 6b24ca4a1a8d ("mm: Use multi-index entries in the page cache")
+Reported-by: syzbot+0d2b0bf32ca5cfd09f2e@syzkaller.appspotmail.com
+Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ lib/test_xarray.c |   22 ++++++++++++++++++++++
+ lib/xarray.c      |    2 ++
+ 2 files changed, 24 insertions(+)
+
+--- a/lib/test_xarray.c
++++ b/lib/test_xarray.c
+@@ -1438,6 +1438,25 @@ unlock:
+       XA_BUG_ON(xa, !xa_empty(xa));
+ }
+ 
++static noinline void check_create_range_5(struct xarray *xa,
++              unsigned long index, unsigned int order)
++{
++      XA_STATE_ORDER(xas, xa, index, order);
++      unsigned int i;
++
++      xa_store_order(xa, index, order, xa_mk_index(index), GFP_KERNEL);
++
++      for (i = 0; i < order + 10; i++) {
++              do {
++                      xas_lock(&xas);
++                      xas_create_range(&xas);
++                      xas_unlock(&xas);
++              } while (xas_nomem(&xas, GFP_KERNEL));
++      }
++
++      xa_destroy(xa);
++}
++
+ static noinline void check_create_range(struct xarray *xa)
+ {
+       unsigned int order;
+@@ -1465,6 +1484,9 @@ static noinline void check_create_range(
+               check_create_range_4(xa, (3U << order) + 1, order);
+               check_create_range_4(xa, (3U << order) - 1, order);
+               check_create_range_4(xa, (1U << 24) + 1, order);
++
++              check_create_range_5(xa, 0, order);
++              check_create_range_5(xa, (1U << order), order);
+       }
+ 
+       check_create_range_3();
+--- a/lib/xarray.c
++++ b/lib/xarray.c
+@@ -722,6 +722,8 @@ void xas_create_range(struct xa_state *x
+ 
+               for (;;) {
+                       struct xa_node *node = xas->xa_node;
++                      if (node->shift >= shift)
++                              break;
+                       xas->xa_node = xa_parent_locked(xas->xa, node);
+                       xas->xa_offset = node->offset - 1;
+                       if (node->offset != 0)