From: Al Viro <viro@ZenIV.linux.org.uk>
To: netdev@vger.kernel.org
Cc: Vasundhara Volam <vasundhara.volam@emulex.com>,
Sathya Perla <sathya.perla@emulex.com>
Subject: [benet] possible endianness bug in be_cmd_txq_create()
Date: Sun, 10 Dec 2017 16:41:20 +0000 [thread overview]
Message-ID: <20171210164120.GS21978@ZenIV.linux.org.uk> (raw)
In be_cmd_txq_create() we have
if (req->hdr.version > 0)
req->if_id = cpu_to_le16(adapter->if_handle);
req->num_pages = PAGES_4K_SPANNED(q_mem->va, q_mem->size);
req->ulp_num = BE_ULP1_NUM;
req->type = BE_ETH_TX_RING_TYPE_STANDARD;
req->cq_id = cpu_to_le16(cq->id);
req->queue_size = be_encoded_q_len(txq->len);
be_cmd_page_addrs_prepare(req->pages, ARRAY_SIZE(req->pages), q_mem);
ver = req->hdr.version;
req points to
struct be_cmd_req_eth_tx_create {
struct be_cmd_req_hdr hdr;
u8 num_pages;
u8 ulp_num;
u16 type;
u16 if_id;
u8 queue_size;
u8 rsvd0;
u32 rsvd1;
u16 cq_id;
u16 rsvd2;
u32 rsvd3[13];
struct phys_addr pages[8];
} __packed;
Everything appears to be consistent with little-endian data - direct
assignments to u8 fields, cpu_to_le16 for cq_id and if_id, phys_addr
array is also filled with little-endian data, so's ->hdr (several
lines prior, by be_wrb_cmd_hdr_prepare()).
The only exception is
req->type = BE_ETH_TX_RING_TYPE_STANDARD;
where we set a 16bit field with host-endian constant (2).
benet is playing silly buggers with swap-in-place in some places, but
it's always 32bit values getting swapped, so this can't be happening
here (num_pages, ulp_num and type form a 32bit-aligned word, and
on big-endian cpu_to_le32() done to it would've ended up with num_pages = 2,
ulp_num = 0, type = 256 + PAGES_4K_SPANNED(q_mem->va, q_mem->size), which is
unlikely to do anything good).
So it really smells like this line should've been
req->type = cpu_to_le16(BE_ETH_TX_RING_TYPE_STANDARD);
I don't have the hardware, so the above is completely untested (caught by
sparse when trying to do endianness annotations in drivers/net), but it
does look like it might be worth a look from benet maintainers.
next reply other threads:[~2017-12-10 16:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-10 16:41 Al Viro [this message]
2017-12-10 18:43 ` [benet] possible endianness bug in be_cmd_txq_create() Al Viro
2017-12-10 20:17 ` Al Viro
2018-01-29 7:33 ` Sathya Perla
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