From 3c9c708c9fc967e389f85bc735e4c1f65d67334e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 31 May 2012 13:39:05 +0200 Subject: [PATCH] block: avoid infinite loop in get_task_io_context() Calling get_task_io_context() on a exiting task which isn't %current can loop forever. This triggers at boot time on my dev machine. BUG: soft lockup - CPU#3 stuck for 22s ! [mountall.1603] Fix this by making create_task_io_context() returns -EBUSY in this case to break the loop. Signed-off-by: Eric Dumazet Cc: Tejun Heo Cc: Andrew Morton Cc: Alan Cox Signed-off-by: Jens Axboe --- block/blk-ioc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/blk-ioc.c b/block/blk-ioc.c index 1e2d53b04858..893b8007c657 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -235,6 +235,7 @@ void ioc_clear_queue(struct request_queue *q) int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node) { struct io_context *ioc; + int ret; ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO, node); @@ -262,9 +263,12 @@ int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node) task->io_context = ioc; else kmem_cache_free(iocontext_cachep, ioc); + + ret = task->io_context ? 0 : -EBUSY; + task_unlock(task); - return 0; + return ret; } /**