This is a note to let you know that I've just added the patch titled
radix-tree: must check __radix_tree_preload() return value
to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
radix-tree-must-check-__radix_tree_preload-return-value.patch
and it can be found in the queue-4.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bc9ae2247ac92fd4d962507bafa3afffff6660ff Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Fri, 8 Sep 2017 16:15:54 -0700
Subject: radix-tree: must check __radix_tree_preload() return value
From: Eric Dumazet <edumazet@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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@xxxxxxxxxx>
Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-4.12/radix-tree-must-check-__radix_tree_preload-return-value.patch