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[PATCH 4.12 09/22] radix-tree: must check __radix_tree_preload() return value

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4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

commit bc9ae2247ac92fd4d962507bafa3afffff6660ff upstream.

__radix_tree_preload() only disables preemption if no error is returned.

So we really need to make sure callers always check the return value.

idr_preload() contract is to always disable preemption, so we need
to add a missing preempt_disable() if an error happened.

Similarly, ida_pre_get() only needs to call preempt_enable() in the
case no error happened.

Link: http://lkml.kernel.org/r/1504637190.15310.62.camel@edumazet-glaptop3.roam.corp.google.com
Fixes: 0a835c4f090a ("Reimplement IDR and IDA using the radix tree")
Fixes: 7ad3d4d85c7a ("ida: Move ida_bitmap to a percpu variable")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 lib/radix-tree.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -463,7 +463,7 @@ radix_tree_node_free(struct radix_tree_n
  * To make use of this facility, the radix tree must be initialised without
  * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
  */
-static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
+static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
 {
 	struct radix_tree_preload *rtp;
 	struct radix_tree_node *node;
@@ -2103,7 +2103,8 @@ EXPORT_SYMBOL(radix_tree_tagged);
  */
 void idr_preload(gfp_t gfp_mask)
 {
-	__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE);
+	if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE))
+		preempt_disable();
 }
 EXPORT_SYMBOL(idr_preload);
 
@@ -2117,13 +2118,13 @@ EXPORT_SYMBOL(idr_preload);
  */
 int ida_pre_get(struct ida *ida, gfp_t gfp)
 {
-	__radix_tree_preload(gfp, IDA_PRELOAD_SIZE);
 	/*
 	 * The IDA API has no preload_end() equivalent.  Instead,
 	 * ida_get_new() can return -EAGAIN, prompting the caller
 	 * to return to the ida_pre_get() step.
 	 */
-	preempt_enable();
+	if (!__radix_tree_preload(gfp, IDA_PRELOAD_SIZE))
+		preempt_enable();
 
 	if (!this_cpu_read(ida_bitmap)) {
 		struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);

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[PATCH 4.12 00/22] 4.12.13-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 18/22] ARM64: dts: marvell: armada-37xx: Fix GIC maintenance interrupt Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 22/22] NFSv4: Fix up mirror allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 20/22] NFS: Fix 2 use after free issues in the I/O code Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 02/22] mtd: nand: hynix: add support for 20nm NAND chips Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 13/22] mm/memory.c: fix mem_cgroup_oom_disable() call missing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 12/22] mm/swapfile.c: fix swapon frontswap_map memory leak on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 06/22] nvme-fabrics: generate spec-compliant UUID NQNs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:10 +0200
  [PATCH 4.12 08/22] rtlwifi: btcoexist: Fix breakage of ant_sel for rtl8723be Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 09/22] radix-tree: must check __radix_tree_preload() return value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 03/22] mtd: nand: mxc: Fix mxc_v1 ooblayout Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 21/22] NFS: Sync the correct byte range during synchronous writes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 07/22] btrfs: resume qgroup rescan on rw remount Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 10/22] selftests/x86/fsgsbase: Test selectors 1, 2, and 3 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 05/22] mtd: nand: qcom: fix config error for BCH Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  [PATCH 4.12 04/22] mtd: nand: qcom: fix read failure without complete bootchain Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-09-12 19:20 +0200
  Re: [PATCH 4.12 00/22] 4.12.13-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-09-13 02:20 +0200
  Re: [PATCH 4.12 00/22] 4.12.13-stable review Guenter Roeck <linux@roeck-us.net> - 2017-09-13 16:40 +0200

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