3.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: T Makphaibulchoke <[email protected]> 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 <[email protected]> Reviewed-by: Ram Pai <[email protected]> Cc: Paul Gortmaker <[email protected]> Cc: Wei Yang <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Cc: Jiri Slaby <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/resource.c | 52 +++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 39 insertions(+), 13 deletions(-) --- a/kernel/resource.c +++ b/kernel/resource.c @@ -736,6 +736,7 @@ static void __init __reserve_region_with struct resource *parent = root; struct resource *conflict; struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC); + struct resource *next_res = NULL; if (!res) return; @@ -745,21 +746,46 @@ static void __init __reserve_region_with res->end = end; res->flags = IORESOURCE_BUSY; - conflict = __request_resource(parent, res); - if (!conflict) - return; - - /* failed, split and try again */ - kfree(res); + while (1) { - /* conflict covered whole area */ - if (conflict->start <= start && conflict->end >= end) - return; + 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 <= 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
