Re: [PATCH] crypto: arm64/aes-blk - fix and move skcipher_walk_done out of kernel_neon_begin,_end

[Jia He <hejianet@gmail.com>]

[+ Ard Biesheuvel]

On 6/8/2018 3:05 PM, Jia He Wrote:
> In a arm64 server(QDF2400),I met a similar might-sleep warning as [1]:
> [    7.019116] BUG: sleeping function called from invalid context at
> ./include/crypto/algapi.h:416
> [    7.027863] in_atomic(): 1, irqs_disabled(): 0, pid: 410, name:
> cryptomgr_test
> [    7.035106] 1 lock held by cryptomgr_test/410:
> [    7.039549]  #0:         (ptrval) (&drbg->drbg_mutex){+.+.}, at:
> drbg_instantiate+0x34/0x398
> [    7.048038] CPU: 9 PID: 410 Comm: cryptomgr_test Not tainted
> 4.17.0-rc6+ #27
> [    7.068228]  dump_backtrace+0x0/0x1c0
> [    7.071890]  show_stack+0x24/0x30
> [    7.075208]  dump_stack+0xb0/0xec
> [    7.078523]  ___might_sleep+0x160/0x238
> [    7.082360]  skcipher_walk_done+0x118/0x2c8
> [    7.086545]  ctr_encrypt+0x98/0x130
> [    7.090035]  simd_skcipher_encrypt+0x68/0xc0
> [    7.094304]  drbg_kcapi_sym_ctr+0xd4/0x1f8
> [    7.098400]  drbg_ctr_update+0x98/0x330
> [    7.102236]  drbg_seed+0x1b8/0x2f0
> [    7.105637]  drbg_instantiate+0x2ac/0x398
> [    7.109646]  drbg_kcapi_seed+0xbc/0x188
> [    7.113482]  crypto_rng_reset+0x4c/0xb0
> [    7.117319]  alg_test_drbg+0xec/0x330
> [    7.120981]  alg_test.part.6+0x1c8/0x3c8
> [    7.124903]  alg_test+0x58/0xa0
> [    7.128044]  cryptomgr_test+0x50/0x58
> [    7.131708]  kthread+0x134/0x138
> [    7.134936]  ret_from_fork+0x10/0x1c
> 
> Seems there is a bug in Ard Biesheuvel's commit.
> Fixes: 683381747270 ("crypto: arm64/aes-blk - move kernel mode neon
> en/disable into loop")
> 
> [1] https://www.spinics.net/lists/linux-crypto/msg33103.html
> 
> Signed-off-by: jia.he@hxt-semitech.com
> ---
>  arch/arm64/crypto/aes-glue.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
> index 253188f..e3e5095 100644
> --- a/arch/arm64/crypto/aes-glue.c
> +++ b/arch/arm64/crypto/aes-glue.c
> @@ -223,8 +223,8 @@ static int ctr_encrypt(struct skcipher_request *req)
>  		kernel_neon_begin();
>  		aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
>  				(u8 *)ctx->key_enc, rounds, blocks, walk.iv);
> -		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
>  		kernel_neon_end();
> +		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
>  	}
>  	if (walk.nbytes) {
>  		u8 __aligned(8) tail[AES_BLOCK_SIZE];
> 

-- 
Cheers,
Jia