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hwrng: cctrng - Fix runtime PM usage counter leak

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pm_runtime_get_sync() increments the device usage counter even when
runtime resume fails. cctrng_read() propagates errors from
cc_trng_pm_get() without scheduling the work that later drops the
counter, so a clock or reset-completion failure in cctrng_resume()
leaves the counter elevated.

Use pm_runtime_resume_and_get(), which drops the usage counter when
resume fails and returns zero on success. This preserves the existing
success path while balancing the error path.

This issue was found by a static analysis checker and confirmed by
manual source review.

Fixes: a583ed310b ("hwrng: cctrng - introduce Arm CryptoCell driver")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ruoyu Wang 2026-08-14 21:39:33 +08:00 committed by Herbert Xu
parent 3244eef8b5
commit 58d27c4154
1 changed files with 1 additions and 6 deletions
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7
drivers/char/hw_random/cctrng.c
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@ -86,12 +86,7 @@ static inline u32 cc_ioread(struct cctrng_drvdata *drvdata, u32 reg)
static int cc_trng_pm_get(struct device *dev)
{
int rc = 0;
rc = pm_runtime_get_sync(dev);
/* pm_runtime_get_sync() can return 1 as a valid return code */
return (rc == 1 ? 0 : rc);
return pm_runtime_resume_and_get(dev);
}
static void cc_trng_pm_put_suspend(struct device *dev)