Comments
Patch
@@ -758,6 +758,7 @@ static void __init __reserve_region_with_split(struct resource *root,
struct resource *parent = root;
struct resource *conflict;
struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
+ struct resource *next_res = NULL;
if (!res)
return;
@@ -767,21 +768,46 @@ static void __init __reserve_region_with_split(struct resource *root,
res->end = end;
res->flags = IORESOURCE_BUSY;
- conflict = __request_resource(parent, res);
- if (!conflict)
- return;
+ while (1) {
- /* failed, split and try again */
- kfree(res);
+ conflict = __request_resource(parent, res);
+ if (!conflict) {
+ if (!next_res)
+ break;
+ res = next_res;
+ next_res = NULL;
+ continue;
+ }
- /* conflict covered whole area */
- if (conflict->start <= start && conflict->end >= end)
- return;
+ /* conflict covered whole area */
+ if (conflict->start <= res->start &&
+ conflict->end >= res->end) {
+ kfree(res);
+ WARN_ON(next_res);
+ break;
+ }
+
+ /* failed, split and try again */
+ if (conflict->start > res->start) {
+ end = res->end;
+ res->end = conflict->start - 1;
+ if (conflict->end < end) {
+ next_res = kzalloc(sizeof(*next_res),
+ GFP_ATOMIC);
+ if (!next_res) {
+ kfree(res);
+ break;
+ }
+ next_res->name = name;
+ next_res->start = conflict->end + 1;
+ next_res->end = end;
+ next_res->flags = IORESOURCE_BUSY;
+ }
+ } else {
+ res->start = conflict->end + 1;
+ }
+ }
- if (conflict->start > start)
- __reserve_region_with_split(root, start, conflict->start-1, name);
- if (conflict->end < end)
- __reserve_region_with_split(root, conflict->end+1, end, name);
}
void __init reserve_region_with_split(struct resource *root,
This is a note to let you know that I have just added a patch titled kernel/resource.c: fix stack overflow in to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From eada91d3628ac4496b6561b02036a23f2fcf652e Mon Sep 17 00:00:00 2001 From: T Makphaibulchoke <tmac@hp.com> Date: Thu, 4 Oct 2012 17:16:55 -0700 Subject: [PATCH] kernel/resource.c: fix stack overflow in __reserve_region_with_split() commit 4965f5667f36a95b41cda6638875bc992bd7d18b upstream. Using a recursive call add a non-conflicting region in __reserve_region_with_split() could result in a stack overflow in the case that the recursive calls are too deep. Convert the recursive calls to an iterative loop to avoid the problem. Tested on a machine containing 135 regions. The kernel no longer panicked with stack overflow. Also tested with code arbitrarily adding regions with no conflict, embedding two consecutive conflicts and embedding two non-consecutive conflicts. Signed-off-by: T Makphaibulchoke <tmac@hp.com> Reviewed-by: Ram Pai <linuxram@us.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@gmail.com> Cc: Wei Yang <weiyang@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- kernel/resource.c | 50 ++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 38 insertions(+), 12 deletions(-) -- 1.7.9.5