Commit ce026cb9 authored by Kim Phillips's avatar Kim Phillips Committed by Herbert Xu
Browse files

crypto: caam - fix possible deadlock condition 



commit "crypto: caam - use non-irq versions of spinlocks for job rings"
made two bad assumptions:

(a) The caam_jr_enqueue lock isn't used in softirq context.
Not true: jr_enqueue can be interrupted by an incoming net
interrupt and the received packet may be sent for encryption,
via caam_jr_enqueue in softirq context, thereby inducing a
deadlock.

This is evidenced when running netperf over an IPSec tunnel
between two P4080's, with spinlock debugging turned on:

[  892.092569] BUG: spinlock lockup on CPU#7, netperf/10634, e8bf5f70
[  892.098747] Call Trace:
[  892.101197] [eff9fc10] [c00084c0] show_stack+0x48/0x15c (unreliable)
[  892.107563] [eff9fc50] [c0239c2c] do_raw_spin_lock+0x16c/0x174
[  892.113399] [eff9fc80] [c0596494] _raw_spin_lock+0x3c/0x50
[  892.118889] [eff9fc90] [c0445e74] caam_jr_enqueue+0xf8/0x250
[  892.124550] [eff9fcd0] [c044a644] aead_decrypt+0x6c/0xc8
[  892.129625] BUG: spinlock lockup on CPU#5, swapper/5/0, e8bf5f70
[  892.129629] Call Trace:
[  892.129637] [effa7c10] [c00084c0] show_stack+0x48/0x15c (unreliable)
[  892.129645] [effa7c50] [c0239c2c] do_raw_spin_lock+0x16c/0x174
[  892.129652] [effa7c80] [c0596494] _raw_spin_lock+0x3c/0x50
[  892.129660] [effa7c90] [c0445e74] caam_jr_enqueue+0xf8/0x250
[  892.129666] [effa7cd0] [c044a644] aead_decrypt+0x6c/0xc8
[  892.129674] [effa7d00] [c0509724] esp_input+0x178/0x334
[  892.129681] [effa7d50] [c0519778] xfrm_input+0x77c/0x818
[  892.129688] [effa7da0] [c050e344] xfrm4_rcv_encap+0x20/0x30
[  892.129697] [effa7db0] [c04b90c8] ip_local_deliver+0x190/0x408
[  892.129703] [effa7de0] [c04b966c] ip_rcv+0x32c/0x898
[  892.129709] [effa7e10] [c048b998] __netif_receive_skb+0x27c/0x4e8
[  892.129715] [effa7e80] [c048d744] netif_receive_skb+0x4c/0x13c
[  892.129726] [effa7eb0] [c03c28ac] _dpa_rx+0x1a8/0x354
[  892.129732] [effa7ef0] [c03c2ac4] ingress_rx_default_dqrr+0x6c/0x108
[  892.129742] [effa7f10] [c0467ae0] qman_poll_dqrr+0x170/0x1d4
[  892.129748] [effa7f40] [c03c153c] dpaa_eth_poll+0x20/0x94
[  892.129754] [effa7f60] [c048dbd0] net_rx_action+0x13c/0x1f4
[  892.129763] [effa7fa0] [c003d1b8] __do_softirq+0x108/0x1b0
[  892.129769] [effa7ff0] [c000df58] call_do_softirq+0x14/0x24
[  892.129775] [ebacfe70] [c0004868] do_softirq+0xd8/0x104
[  892.129780] [ebacfe90] [c003d5a4] irq_exit+0xb8/0xd8
[  892.129786] [ebacfea0] [c0004498] do_IRQ+0xa4/0x1b0
[  892.129792] [ebacfed0] [c000fad8] ret_from_except+0x0/0x18
[  892.129798] [ebacff90] [c0009010] cpu_idle+0x94/0xf0
[  892.129804] [ebacffb0] [c059ff88] start_secondary+0x42c/0x430
[  892.129809] [ebacfff0] [c0001e28] __secondary_start+0x30/0x84
[  892.281474]
[  892.282959] [eff9fd00] [c0509724] esp_input+0x178/0x334
[  892.288186] [eff9fd50] [c0519778] xfrm_input+0x77c/0x818
[  892.293499] [eff9fda0] [c050e344] xfrm4_rcv_encap+0x20/0x30
[  892.299074] [eff9fdb0] [c04b90c8] ip_local_deliver+0x190/0x408
[  892.304907] [eff9fde0] [c04b966c] ip_rcv+0x32c/0x898
[  892.309872] [eff9fe10] [c048b998] __netif_receive_skb+0x27c/0x4e8
[  892.315966] [eff9fe80] [c048d744] netif_receive_skb+0x4c/0x13c
[  892.321803] [eff9feb0] [c03c28ac] _dpa_rx+0x1a8/0x354
[  892.326855] [eff9fef0] [c03c2ac4] ingress_rx_default_dqrr+0x6c/0x108
[  892.333212] [eff9ff10] [c0467ae0] qman_poll_dqrr+0x170/0x1d4
[  892.338872] [eff9ff40] [c03c153c] dpaa_eth_poll+0x20/0x94
[  892.344271] [eff9ff60] [c048dbd0] net_rx_action+0x13c/0x1f4
[  892.349846] [eff9ffa0] [c003d1b8] __do_softirq+0x108/0x1b0
[  892.355338] [eff9fff0] [c000df58] call_do_softirq+0x14/0x24
[  892.360910] [e7169950] [c0004868] do_softirq+0xd8/0x104
[  892.366135] [e7169970] [c003d5a4] irq_exit+0xb8/0xd8
[  892.371101] [e7169980] [c0004498] do_IRQ+0xa4/0x1b0
[  892.375979] [e71699b0] [c000fad8] ret_from_except+0x0/0x18
[  892.381466] [e7169a70] [c0445e74] caam_jr_enqueue+0xf8/0x250
[  892.387127] [e7169ab0] [c044ad4c] aead_givencrypt+0x6ac/0xa70
[  892.392873] [e7169b20] [c050a0b8] esp_output+0x2b4/0x570
[  892.398186] [e7169b80] [c0519b9c] xfrm_output_resume+0x248/0x7c0
[  892.404194] [e7169bb0] [c050e89c] xfrm4_output_finish+0x18/0x28
[  892.410113] [e7169bc0] [c050e8f4] xfrm4_output+0x48/0x98
[  892.415427] [e7169bd0] [c04beac0] ip_local_out+0x48/0x98
[  892.420740] [e7169be0] [c04bec7c] ip_queue_xmit+0x16c/0x490
[  892.426314] [e7169c10] [c04d6128] tcp_transmit_skb+0x35c/0x9a4
[  892.432147] [e7169c70] [c04d6f98] tcp_write_xmit+0x200/0xa04
[  892.437808] [e7169cc0] [c04c8ccc] tcp_sendmsg+0x994/0xcec
[  892.443213] [e7169d40] [c04eebfc] inet_sendmsg+0xd0/0x164
[  892.448617] [e7169d70] [c04792f8] sock_sendmsg+0x8c/0xbc
[  892.453931] [e7169e40] [c047aecc] sys_sendto+0xc0/0xfc
[  892.459069] [e7169f10] [c047b934] sys_socketcall+0x110/0x25c
[  892.464729] [e7169f40] [c000f480] ret_from_syscall+0x0/0x3c

(b) since the caam_jr_dequeue lock is only used in bh context,
then semantically it should use _bh spin_lock types.  spin_lock_bh
semantics are to disable back-halves, and used when a lock is shared
between softirq (bh) context and process and/or h/w IRQ context.
Since the lock is only used within softirq context, and this tasklet
is atomic, there is no need to do the additional work to disable
back halves.

This patch adds back-half disabling protection to caam_jr_enqueue
spin_locks to fix (a), and drops it from caam_jr_dequeue to fix (b).

Signed-off-by: default avatarKim Phillips <kim.phillips@freescale.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 76f16f83

drivers/crypto/caam/jr.c

+5 −5
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ static void caam_jr_dequeue(unsigned long devarg) 


		head = ACCESS_ONCE(jrp->head);



		spin_lock_bh(&jrp->outlock);

		spin_lock(&jrp->outlock);



		sw_idx = tail = jrp->tail;

		hw_idx = jrp->out_ring_read_index;
@@ -115,7 +115,7 @@ static void caam_jr_dequeue(unsigned long devarg) 
			jrp->tail = tail;

		}



		spin_unlock_bh(&jrp->outlock);

		spin_unlock(&jrp->outlock);



		/* Finally, execute user's callback */

		usercall(dev, userdesc, userstatus, userarg);
@@ -236,14 +236,14 @@ int caam_jr_enqueue(struct device *dev, u32 *desc, 
		return -EIO;

	}



	spin_lock(&jrp->inplock);

	spin_lock_bh(&jrp->inplock);



	head = jrp->head;

	tail = ACCESS_ONCE(jrp->tail);



	if (!rd_reg32(&jrp->rregs->inpring_avail) ||

	    CIRC_SPACE(head, tail, JOBR_DEPTH) <= 0) {

		spin_unlock(&jrp->inplock);

		spin_unlock_bh(&jrp->inplock);

		dma_unmap_single(dev, desc_dma, desc_size, DMA_TO_DEVICE);

		return -EBUSY;

	}
@@ -265,7 +265,7 @@ int caam_jr_enqueue(struct device *dev, u32 *desc, 


	wr_reg32(&jrp->rregs->inpring_jobadd, 1);



	spin_unlock(&jrp->inplock);

	spin_unlock_bh(&jrp->inplock);



	return 0;

}

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