2021-10-19 06:43:16

by Li, Meng

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

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: [email protected]
Signed-off-by: Meng Li <[email protected]>
---
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

2021-10-29 12:32:07

by Herbert Xu

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

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 <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt