Hi Salvatore, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.16-rc5 next-20180314] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Salvatore-Mesoraca/crypto-ctr-avoid-VLA-use/20180315-213008 config: x86_64-randconfig-x014-201810 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): crypto/ctr.c: In function 'crypto_ctr_crypt': >> crypto/ctr.c:156:3: warning: 'tmp2' may be used uninitialized in this function [-Wmaybe-uninitialized] kfree(tmp2); ^~~~~~~~~~~ crypto/ctr.c:133:18: note: 'tmp2' was declared here u8 *keystream, *tmp2; ^~~~ vim +/tmp2 +156 crypto/ctr.c 121 122 static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk, 123 struct crypto_cipher *tfm) 124 { 125 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = 126 crypto_cipher_alg(tfm)->cia_encrypt; 127 unsigned int bsize = crypto_cipher_blocksize(tfm); 128 unsigned long alignmask = crypto_cipher_alignmask(tfm); 129 unsigned int nbytes = walk->nbytes; 130 u8 *ctrblk = walk->iv; 131 u8 *src = walk->src.virt.addr; 132 DECLARE_CIPHER_BUFFER(tmp); 133 u8 *keystream, *tmp2; 134 135 if (CHECK_CIPHER_BUFFER(tmp, bsize, alignmask)) 136 keystream = tmp; 137 else { 138 tmp2 = kmalloc(bsize + alignmask, GFP_ATOMIC); 139 if (!tmp2) 140 return -ENOMEM; 141 keystream = PTR_ALIGN(tmp2 + 0, alignmask + 1); 142 } 143 144 do { 145 /* create keystream */ 146 fn(crypto_cipher_tfm(tfm), keystream, ctrblk); 147 crypto_xor(src, keystream, bsize); 148 149 /* increment counter in counterblock */ 150 crypto_inc(ctrblk, bsize); 151 152 src += bsize; 153 } while ((nbytes -= bsize) >= bsize); 154 155 if (unlikely(keystream != tmp)) > 156 kfree(tmp2); 157 return nbytes; 158 } 159 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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