Commit 317be9c6 authored by Krzysztof Karas's avatar Krzysztof Karas Committed by Andi Shyti
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drm/i915/gt: Protect against overflow in active_engine() 



It is unlikely, but possible for the first call to
intel_context_create() to fail with -ENOMEM, which would result
in entering the following code block and decrementing "count",
when it is set to 0 (initial condition in the for loop).

Protect from overflowing the variable by checking for 0 value
of "count" before entering the loop.

Signed-off-by: default avatarKrzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: default avatarSebastian Brzezinka <sebastian.brzezinka@intel.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: default avatarAndi Shyti <andi.shyti@linux.intel.com>
Link: https://lore.kernel.org/r/pogr74jktdqehrfap4tjky23ees4x7erh5dwgg5jb2n522cfkw@kpnxe4qzx4pj
parent f768ebbb

drivers/gpu/drm/i915/gt/selftest_hangcheck.c

+2 −0
Original line number Diff line number Diff line
@@ -904,6 +904,8 @@ static void active_engine(struct kthread_work *work) 
			arg->result = PTR_ERR(ce[count]);

			pr_err("[%s] Create context #%ld failed: %d!\n",

			       engine->name, count, arg->result);

			if (!count)

				return;

			while (--count)

				intel_context_put(ce[count]);

			return;