> On Oct 2, 2017, at 7:25 PM, Jia-Ju Bai <baijiaju1990@xxxxxxx> wrote: > > The SCTP program may sleep under a spinlock, and the function call path is: > sctp_generate_t3_rtx_event (acquire the spinlock) > sctp_do_sm > sctp_side_effects > sctp_cmd_interpreter > sctp_make_init_ack > sctp_pack_cookie > crypto_shash_setkey > shash_setkey_unaligned > kmalloc(GFP_KERNEL) > I'm going to go out on a limb here: why on Earth is out crypto API so full of indirection that we allocate memory at all here? We're synchronously computing a hash of a small amount of data using either HMAC-SHA1 or HMAC-SHA256 (determined at runtime) if I read it right. There's a sane way to do this that doesn't need kmalloc, alloca, or fancy indirection. And then there's crypto_shash_xyz(). --Andy, who is sick of seeing stupid bugs caused by the fact that it's basically impossible to use the crypto API in a sane way. P.S. gnulib has: int hmac_sha256 (const void *key, size_t keylen, const void *in, size_t inlen, void *resbuf); An init/update/final-style API would be nice, but something like this would be a phenomenal improvement over what we have.
