Messages in this thread | | | Date | Fri, 1 Jun 2012 14:06:01 +0900 | From | Tejun Heo <> | Subject | Re: [PATCH] block: avoid infinite loop in get_task_io_context() |
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Hello, Eric, Jens.
On Thu, May 31, 2012 at 12:38:26PM +0200, Eric Dumazet wrote: > [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 <edumazet@google.com> > Cc: Tejun Heo <tj@kernel.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Alan Cox <alan@linux.intel.com> > --- > 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 1e2d53b..893b800 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;
Ah, right. This seems correct to me.
FWIW-late-Acked-by: Tejun Heo <tj@kernel.org>
Thanks. :)
-- tejun
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