Doug / smarc-fsl-linux-kernel

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Commit 3c9c708c9fc967e389f85bc735e4c1f65d67334e

Authored by Eric Dumazet
Committed by Jens Axboe
1 parent b77874c969
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

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>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Showing 1 changed file with 5 additions and 1 deletions Side-by-side Diff

... ... @@ -235,6 +235,7 @@
235 235 int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
236 236 {
237 237 struct io_context *ioc;
  238 + int ret;
238 239  
239 240 ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
240 241 node);
241 242  
... ... @@ -262,9 +263,12 @@
262 263 task->io_context = ioc;
263 264 else
264 265 kmem_cache_free(iocontext_cachep, ioc);
  266 +
  267 + ret = task->io_context ? 0 : -EBUSY;
  268 +
265 269 task_unlock(task);
266 270  
267   - return 0;
  271 + return ret;
268 272 }
269 273  
270 274 /**