[PATCH] driver: crypto: caam: instead this_cpu_ptr with raw_cpu_ptr

[PATCH] driver: crypto: caam: instead this_cpu_ptr with raw_cpu_ptr

[Meng Li]

When enable the kernel debug config, there is below calltrace detected:
BUG: using smp_processor_id() in preemptible [00000000] code: cryptomgr_test/339
caller is debug_smp_processor_id+0x20/0x30
CPU: 9 PID: 339 Comm: cryptomgr_test Not tainted 5.10.63-yocto-standard #1
Hardware name: NXP Layerscape LX2160ARDB (DT)
Call trace:
 dump_backtrace+0x0/0x1a0
 show_stack+0x24/0x30
 dump_stack+0xf0/0x13c
 check_preemption_disabled+0x100/0x110
 debug_smp_processor_id+0x20/0x30
 dpaa2_caam_enqueue+0x10c/0x25c
 ......
 cryptomgr_test+0x38/0x60
 kthread+0x158/0x164
 ret_from_fork+0x10/0x38
According to the comment in commit ac5d15b4519f("crypto: caam/qi2
 - use affine DPIOs "), it doesn't matter whether preemption is
disable or not. So, only instead this_cpu_ptr with raw_cpu_ptr to
avoid above call trace.

Fixes: ac5d15b4519f ("crypto: caam/qi2 - use affine DPIOs")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
---
 drivers/crypto/caam/caamalg_qi2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/caam/caamalg_qi2.c b/drivers/crypto/caam/caamalg_qi2.c
index 86fc349abc59..39db403ba8b4 100644
--- a/drivers/crypto/caam/caamalg_qi2.c
+++ b/drivers/crypto/caam/caamalg_qi2.c
@@ -5766,7 +5766,7 @@ int dpaa2_caam_enqueue(struct device *dev, struct caam_request *req)
 	dpaa2_fd_set_len(&fd, dpaa2_fl_get_len(&req->fd_flt[1]));
 	dpaa2_fd_set_flc(&fd, req->flc_dma);
 
-	ppriv = this_cpu_ptr(priv->ppriv);
+	ppriv = raw_cpu_ptr(priv->ppriv);
 	for (i = 0; i < (priv->dpseci_attr.num_tx_queues << 1); i++) {
 		err = dpaa2_io_service_enqueue_fq(ppriv->dpio, ppriv->req_fqid,
 						  &fd);
-- 
2.17.1

Re: [PATCH] driver: crypto: caam: instead this_cpu_ptr with raw_cpu_ptr

[Herbert Xu]

On Tue, Oct 19, 2021 at 02:37:19PM +0800, Meng Li wrote:
> When enable the kernel debug config, there is below calltrace detected:
> BUG: using smp_processor_id() in preemptible [00000000] code: cryptomgr_test/339
> caller is debug_smp_processor_id+0x20/0x30
> CPU: 9 PID: 339 Comm: cryptomgr_test Not tainted 5.10.63-yocto-standard #1
> Hardware name: NXP Layerscape LX2160ARDB (DT)
> Call trace:
>  dump_backtrace+0x0/0x1a0
>  show_stack+0x24/0x30
>  dump_stack+0xf0/0x13c
>  check_preemption_disabled+0x100/0x110
>  debug_smp_processor_id+0x20/0x30
>  dpaa2_caam_enqueue+0x10c/0x25c
>  ......
>  cryptomgr_test+0x38/0x60
>  kthread+0x158/0x164
>  ret_from_fork+0x10/0x38
> According to the comment in commit ac5d15b4519f("crypto: caam/qi2
>  - use affine DPIOs "), it doesn't matter whether preemption is
> disable or not. So, only instead this_cpu_ptr with raw_cpu_ptr to
> avoid above call trace.

Please put the reason why raw is safe into a comment in the code.
Readers shouldn't need to run git whatschanged to figure out why
this is safe.

Thanks,
-- 
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