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author | shamir rabinovitch <shamir.rabinovitch@oracle.com> | 2018-12-16 09:01:09 +0200 |
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committer | David S. Miller <davem@davemloft.net> | 2018-12-19 10:27:58 -0800 |
commit | c75ab8a55ac1083c232e4407f52b0cadae6c1e0e (patch) | |
tree | e83b619d72b6c229928260b1a9644c79ba08dda5 /net/rds/message.c | |
parent | ea010070d0a7497253d5a6f919f6dd107450b31a (diff) | |
download | linux-stable-c75ab8a55ac1083c232e4407f52b0cadae6c1e0e.tar.gz linux-stable-c75ab8a55ac1083c232e4407f52b0cadae6c1e0e.tar.bz2 linux-stable-c75ab8a55ac1083c232e4407f52b0cadae6c1e0e.zip |
net/rds: remove user triggered WARN_ON in rds_sendmsg
per comment from Leon in rdma mailing list
https://lkml.org/lkml/2018/10/31/312 :
Please don't forget to remove user triggered WARN_ON.
https://lwn.net/Articles/769365/
"Greg Kroah-Hartman raised the problem of core kernel API code that will
use WARN_ON_ONCE() to complain about bad usage; that will not generate
the desired result if WARN_ON_ONCE() is configured to crash the machine.
He was told that the code should just call pr_warn() instead, and that
the called function should return an error in such situations. It was
generally agreed that any WARN_ON() or WARN_ON_ONCE() calls that can be
triggered from user space need to be fixed."
in addition harden rds_sendmsg to detect and overcome issues with
invalid sg count and fail the sendmsg.
Suggested-by: Leon Romanovsky <leon@kernel.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: shamir rabinovitch <shamir.rabinovitch@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds/message.c')
-rw-r--r-- | net/rds/message.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/net/rds/message.c b/net/rds/message.c index 4b00b1152a5f..f139420ba1f6 100644 --- a/net/rds/message.c +++ b/net/rds/message.c @@ -308,16 +308,27 @@ out: /* * RDS ops use this to grab SG entries from the rm's sg pool. */ -struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents) +struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents, + int *ret) { struct scatterlist *sg_first = (struct scatterlist *) &rm[1]; struct scatterlist *sg_ret; - WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs); - WARN_ON(!nents); + if (WARN_ON(!ret)) + return NULL; - if (rm->m_used_sgs + nents > rm->m_total_sgs) + if (nents <= 0) { + pr_warn("rds: alloc sgs failed! nents <= 0\n"); + *ret = -EINVAL; return NULL; + } + + if (rm->m_used_sgs + nents > rm->m_total_sgs) { + pr_warn("rds: alloc sgs failed! total %d used %d nents %d\n", + rm->m_total_sgs, rm->m_used_sgs, nents); + *ret = -ENOMEM; + return NULL; + } sg_ret = &sg_first[rm->m_used_sgs]; sg_init_table(sg_ret, nents); @@ -332,6 +343,7 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in unsigned int i; int num_sgs = ceil(total_len, PAGE_SIZE); int extra_bytes = num_sgs * sizeof(struct scatterlist); + int ret; rm = rds_message_alloc(extra_bytes, GFP_NOWAIT); if (!rm) @@ -340,10 +352,10 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in set_bit(RDS_MSG_PAGEVEC, &rm->m_flags); rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len); rm->data.op_nents = ceil(total_len, PAGE_SIZE); - rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs); + rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs, &ret); if (!rm->data.op_sg) { rds_message_put(rm); - return ERR_PTR(-ENOMEM); + return ERR_PTR(ret); } for (i = 0; i < rm->data.op_nents; ++i) { |