Messages in this thread Patch in this message | | | From | T Makphaibulchoke <> | Subject | [PATCH v2] kernel/resource.c: fix stack overflow in __reserve_region_with_split | Date | Fri, 31 Aug 2012 15:04:25 -0600 |
| |
Using recurvise call to try adding a non-conflicting region in the function __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.
Signed-off-by: T Makphaibulchoke <tmac@hp.com>
-- Change since v1: * Fixing __resrve_region_with_split() to ensure a reqioon reserve request is satisfied to the fullest extent, minus any overlapping conflicting regions. --- kernel/resource.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 files changed, 35 insertions(+), 12 deletions(-)
diff --git a/kernel/resource.c b/kernel/resource.c index 34d4588..f0cdeb6 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -763,6 +763,7 @@ 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; @@ -772,21 +773,43 @@ 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(*res), GFP_ATOMIC); + if (!next_res) { + kfree(res); + break; + } + next_res->start = conflict->end + 1; + next_res->end = end; + } + } 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, -- 1.7.1
| |