From: Anatoly Pugachev <matorola@xxxxxxxxx> Date: Wed, 31 May 2017 14:56:52 +0300 > While debugging occasional crc32c checksum errors with xfs disk reads on > sparc64 (T5 [sun4v] 3.6 GHz CPU ldom, debian unstable/sid), Eric have found > that crc32c sometimes returns wrong checksum for data. Eric made a simple > test kernel module (included), which produce the following results on my > sparc64 machines: I don't think that crc32c() is thread safe because of the way it is implemented with a shared TFM crypto object allocated once at boot time. I think you are seeing the corruption any time an interrupt comes in on the same cpu as your test module is running on and does a crc32c() calculation, corrupting the context key value being used by your invocation. At least that's my guess, I could have misread how the key is stored and managed around operations. Can you try something like disabling cpu IRQs around the crc32c() function in lib/libcrc32c.c? Something like: u32 retval; local_irq_disable(); shash->tfm = tfm; shash->flags = 0; *ctx = crc; err = crypto_shash_update(shash, address, length); BUG_ON(err); retval = *ctx; local_irq_enable(); return retval; Thanks.
