From 6c95483b768c62f8ee933ae08a1bdbcb78b5410f Mon Sep 17 00:00:00 2001 From: Jag Raman Date: Fri, 9 Jun 2017 12:29:31 -0400 Subject: [PATCH] sparc64: ldc abort during vds iso boot Orabug: 20902628 When an ldc control-only packet is received during data exchange in read_nonraw(), a new rx head is calculated but the rx queue head is not actually advanced (rx_set_head() is not called) and a branch is taken to 'no_data' at which point two things can happen depending on the value of the newly calculated rx head and the current rx tail: - If the rx queue is determined to be not empty, then the wrong packet is picked up. - If the rx queue is determined to be empty, then a read error (EAGAIN) is eventually returned since it is falsely assumed that more data was expected. The fix is to update the rx head and return in case of a control only packet during data exchange. Signed-off-by: Jagannathan Raman Reviewed-by: Aaron Young Reviewed-by: Alexandre Chartre Reviewed-by: Bijan Mottahedeh Reviewed-by: Liam Merwick Signed-off-by: David S. Miller --- arch/sparc/kernel/ldc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/sparc/kernel/ldc.c b/arch/sparc/kernel/ldc.c index 639da7b53e83..47817b78ebfc 100644 --- a/arch/sparc/kernel/ldc.c +++ b/arch/sparc/kernel/ldc.c @@ -1778,9 +1778,14 @@ static int read_nonraw(struct ldc_channel *lp, void *buf, unsigned int size) lp->rcv_nxt = p->seqid; + /* + * If this is a control-only packet, there is nothing + * else to do but advance the rx queue since the packet + * was already processed above. + */ if (!(p->type & LDC_DATA)) { new = rx_advance(lp, new); - goto no_data; + break; } if (p->stype & (LDC_ACK | LDC_NACK)) { err = data_ack_nack(lp, p); -- 2.20.1