| Message ID | 20211201063041.GC684@gondor.apana.org.au (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | crypto: stm32 - Revert broken pm_runtime_resume_and_get changes | expand |
On 01.12.2021 07:30, Herbert Xu wrote: > On Sat, Nov 27, 2021 at 02:39:52PM +0100, Heiner Kallweit wrote: >> When discussing whether pm_runtime_resume_and_get() should be annotated as >> __must_check, I became aware of RPM usage in crypto/stm32. >> >> Following two patches replace usage of pm_runtime_get_sync() with >> pm_runtime_resume_and_get() w/o checking the return code. >> >> 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak on stm32-cryp.c") >> 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak on stm32-hash.c") >> >> This results in RPM usage like the following in stm32_hash_export(): >> >> pm_runtime_resume_and_get(hdev->dev); >> ... >> pm_runtime_mark_last_busy(hdev->dev); >> pm_runtime_put_autosuspend(hdev->dev); >> >> This is broken. After pm_runtime_resume_and_get() the usage count may be >> incremented or not. If not, then the call to pm_runtime_put_autosuspend() >> results in exactly the imbalance that the patch claims to fix. >> >> Therefore I think both patches should be reverted, or the return code >> of pm_runtime_resume_and_get() has to be checked and properly handled >> in the driver logic. > > I agree. But we can't revert them completely because it does > fix some genuine issues with the ones where we do check the error > code. What about this patch? Looks good to me, thanks! > > ---8<--- > We should not call pm_runtime_resume_and_get where the reference > count is expected to be incremented unconditionally. This patch > reverts these calls to the original unconditional get_sync call. > > Reported-by: Heiner Kallweit <hkallweit1@gmail.com> > Fixes: 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak...") > Fixes: 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak...") > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> > > diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c > index 7389a0536ff0..05087831e199 100644 > --- a/drivers/crypto/stm32/stm32-cryp.c > +++ b/drivers/crypto/stm32/stm32-cryp.c > @@ -542,7 +542,7 @@ static int stm32_cryp_hw_init(struct stm32_cryp *cryp) > int ret; > u32 cfg, hw_mode; > > - pm_runtime_resume_and_get(cryp->dev); > + pm_runtime_get_sync(cryp->dev); > > /* Disable interrupt */ > stm32_cryp_write(cryp, CRYP_IMSCR, 0); > diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c > index 389de9e3302d..d33006d43f76 100644 > --- a/drivers/crypto/stm32/stm32-hash.c > +++ b/drivers/crypto/stm32/stm32-hash.c > @@ -813,7 +813,7 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err) > static int stm32_hash_hw_init(struct stm32_hash_dev *hdev, > struct stm32_hash_request_ctx *rctx) > { > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > if (!(HASH_FLAGS_INIT & hdev->flags)) { > stm32_hash_write(hdev, HASH_CR, HASH_CR_INIT); > @@ -962,7 +962,7 @@ static int stm32_hash_export(struct ahash_request *req, void *out) > u32 *preg; > unsigned int i; > > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > while ((stm32_hash_read(hdev, HASH_SR) & HASH_SR_BUSY)) > cpu_relax(); > @@ -1000,7 +1000,7 @@ static int stm32_hash_import(struct ahash_request *req, const void *in) > > preg = rctx->hw_context; > > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > stm32_hash_write(hdev, HASH_IMR, *preg++); > stm32_hash_write(hdev, HASH_STR, *preg++); >
On Wed, Dec 1, 2021 at 7:30 AM Herbert Xu <herbert@gondor.apana.org.au> wrote: > > On Sat, Nov 27, 2021 at 02:39:52PM +0100, Heiner Kallweit wrote: > > When discussing whether pm_runtime_resume_and_get() should be annotated as > > __must_check, I became aware of RPM usage in crypto/stm32. > > > > Following two patches replace usage of pm_runtime_get_sync() with > > pm_runtime_resume_and_get() w/o checking the return code. > > > > 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak on stm32-cryp.c") > > 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak on stm32-hash.c") > > > > This results in RPM usage like the following in stm32_hash_export(): > > > > pm_runtime_resume_and_get(hdev->dev); > > ... > > pm_runtime_mark_last_busy(hdev->dev); > > pm_runtime_put_autosuspend(hdev->dev); > > > > This is broken. After pm_runtime_resume_and_get() the usage count may be > > incremented or not. If not, then the call to pm_runtime_put_autosuspend() > > results in exactly the imbalance that the patch claims to fix. > > > > Therefore I think both patches should be reverted, or the return code > > of pm_runtime_resume_and_get() has to be checked and properly handled > > in the driver logic. > > I agree. But we can't revert them completely because it does > fix some genuine issues with the ones where we do check the error > code. What about this patch? > > ---8<--- > We should not call pm_runtime_resume_and_get where the reference > count is expected to be incremented unconditionally. This patch > reverts these calls to the original unconditional get_sync call. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> The rule of thumb is to use pm_runtime_resume_and_get() if you want to check the return value (and act on it) and pm_runtime_get_sync() otherwise. > Reported-by: Heiner Kallweit <hkallweit1@gmail.com> > Fixes: 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak...") > Fixes: 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak...") > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> > > diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c > index 7389a0536ff0..05087831e199 100644 > --- a/drivers/crypto/stm32/stm32-cryp.c > +++ b/drivers/crypto/stm32/stm32-cryp.c > @@ -542,7 +542,7 @@ static int stm32_cryp_hw_init(struct stm32_cryp *cryp) > int ret; > u32 cfg, hw_mode; > > - pm_runtime_resume_and_get(cryp->dev); > + pm_runtime_get_sync(cryp->dev); > > /* Disable interrupt */ > stm32_cryp_write(cryp, CRYP_IMSCR, 0); > diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c > index 389de9e3302d..d33006d43f76 100644 > --- a/drivers/crypto/stm32/stm32-hash.c > +++ b/drivers/crypto/stm32/stm32-hash.c > @@ -813,7 +813,7 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err) > static int stm32_hash_hw_init(struct stm32_hash_dev *hdev, > struct stm32_hash_request_ctx *rctx) > { > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > if (!(HASH_FLAGS_INIT & hdev->flags)) { > stm32_hash_write(hdev, HASH_CR, HASH_CR_INIT); > @@ -962,7 +962,7 @@ static int stm32_hash_export(struct ahash_request *req, void *out) > u32 *preg; > unsigned int i; > > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > while ((stm32_hash_read(hdev, HASH_SR) & HASH_SR_BUSY)) > cpu_relax(); > @@ -1000,7 +1000,7 @@ static int stm32_hash_import(struct ahash_request *req, const void *in) > > preg = rctx->hw_context; > > - pm_runtime_resume_and_get(hdev->dev); > + pm_runtime_get_sync(hdev->dev); > > stm32_hash_write(hdev, HASH_IMR, *preg++); > stm32_hash_write(hdev, HASH_STR, *preg++); > -- > Email: Herbert Xu <herbert@gondor.apana.org.au> > Home Page: http://gondor.apana.org.au/~herbert/ > PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c index 7389a0536ff0..05087831e199 100644 --- a/drivers/crypto/stm32/stm32-cryp.c +++ b/drivers/crypto/stm32/stm32-cryp.c @@ -542,7 +542,7 @@ static int stm32_cryp_hw_init(struct stm32_cryp *cryp) int ret; u32 cfg, hw_mode; - pm_runtime_resume_and_get(cryp->dev); + pm_runtime_get_sync(cryp->dev); /* Disable interrupt */ stm32_cryp_write(cryp, CRYP_IMSCR, 0); diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c index 389de9e3302d..d33006d43f76 100644 --- a/drivers/crypto/stm32/stm32-hash.c +++ b/drivers/crypto/stm32/stm32-hash.c @@ -813,7 +813,7 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err) static int stm32_hash_hw_init(struct stm32_hash_dev *hdev, struct stm32_hash_request_ctx *rctx) { - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); if (!(HASH_FLAGS_INIT & hdev->flags)) { stm32_hash_write(hdev, HASH_CR, HASH_CR_INIT); @@ -962,7 +962,7 @@ static int stm32_hash_export(struct ahash_request *req, void *out) u32 *preg; unsigned int i; - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); while ((stm32_hash_read(hdev, HASH_SR) & HASH_SR_BUSY)) cpu_relax(); @@ -1000,7 +1000,7 @@ static int stm32_hash_import(struct ahash_request *req, const void *in) preg = rctx->hw_context; - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); stm32_hash_write(hdev, HASH_IMR, *preg++); stm32_hash_write(hdev, HASH_STR, *preg++);