提交 86357b19 编写于 作者: A Andy Grover 提交者: David S. Miller

RDS: Fix potential race around rds_i[bw]_allocation

"At rds_ib_recv_refill_one(), it first executes atomic_read(&rds_ib_allocation)
for if-condition checking,

and then executes atomic_inc(&rds_ib_allocation) if the condition was
not satisfied.

However, if any other code which updates rds_ib_allocation executes
between these two atomic operation executions,
it seems that it may result race condition. (especially when
rds_ib_allocation + 1 == rds_ib_sysctl_max_recv_allocation)"

This patch fixes this by using atomic_inc_unless to eliminate the
possibility of allocating more than rds_ib_sysctl_max_recv_allocation
and then decrementing the count if the allocation fails. It also
makes an identical change to the iwarp transport.
Reported-by: NShin Hong <hongshin@gmail.com>
Signed-off-by: NAndy Grover <andy.grover@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 244546f0
master alk-4.19.24 alk-4.19.30 alk-4.19.34 alk-4.19.36 alk-4.19.43 alk-4.19.48 alk-4.19.57 ck-4.19.67 ck-4.19.81 ck-4.19.91 github/fork/deepanshu1422/fix-typo-in-comment github/fork/haosdent/fix-typo linux-next v4.19.91 v4.19.90 v4.19.89 v4.19.88 v4.19.87 v4.19.86 v4.19.85 v4.19.84 v4.19.83 v4.19.82 v4.19.81 v4.19.80 v4.19.79 v4.19.78 v4.19.77 v4.19.76 v4.19.75 v4.19.74 v4.19.73 v4.19.72 v4.19.71 v4.19.70 v4.19.69 v4.19.68 v4.19.67 v4.19.66 v4.19.65 v4.19.64 v4.19.63 v4.19.62 v4.19.61 v4.19.60 v4.19.59 v4.19.58 v4.19.57 v4.19.56 v4.19.55 v4.19.54 v4.19.53 v4.19.52 v4.19.51 v4.19.50 v4.19.49 v4.19.48 v4.19.47 v4.19.46 v4.19.45 v4.19.44 v4.19.43 v4.19.42 v4.19.41 v4.19.40 v4.19.39 v4.19.38 v4.19.37 v4.19.36 v4.19.35 v4.19.34 v4.19.33 v4.19.32 v4.19.31 v4.19.30 v4.19.29 v4.19.28 v4.19.27 v4.19.26 v4.19.25 v4.19.24 v4.19.23 v4.19.22 v4.19.21 v4.19.20 v4.19.19 v4.19.18 v4.19.17 v4.19.16 v4.19.15 v4.19.14 v4.19.13 v4.19.12 v4.19.11 v4.19.10 v4.19.9 v4.19.8 v4.19.7 v4.19.6 v4.19.5 v4.19.4 v4.19.3 v4.19.2 v4.19.1 v4.19 v4.19-rc8 v4.19-rc7 v4.19-rc6 v4.19-rc5 v4.19-rc4 v4.19-rc3 v4.19-rc2 v4.19-rc1 ck-release-21 ck-release-20 ck-release-19.2 ck-release-19.1 ck-release-19 ck-release-18 ck-release-17.2 ck-release-17.1 ck-release-17 ck-release-16 ck-release-15.1 ck-release-15 ck-release-14 ck-release-13.2 ck-release-13 ck-release-12 ck-release-11 ck-release-10 ck-release-9 ck-release-7 alk-release-15 alk-release-14 alk-release-13.2 alk-release-13 alk-release-12 alk-release-11 alk-release-10 alk-release-9 alk-release-7
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......@@ -143,15 +143,16 @@ static int rds_ib_recv_refill_one(struct rds_connection *conn,
int ret = -ENOMEM;
if (recv->r_ibinc == NULL) {
if (atomic_read(&rds_ib_allocation) >= rds_ib_sysctl_max_recv_allocation) {
if (!atomic_add_unless(&rds_ib_allocation, 1, rds_ib_sysctl_max_recv_allocation)) {
rds_ib_stats_inc(s_ib_rx_alloc_limit);
goto out;
}
recv->r_ibinc = kmem_cache_alloc(rds_ib_incoming_slab,
kptr_gfp);
if (recv->r_ibinc == NULL)
if (recv->r_ibinc == NULL) {
atomic_dec(&rds_ib_allocation);
goto out;
atomic_inc(&rds_ib_allocation);
}
INIT_LIST_HEAD(&recv->r_ibinc->ii_frags);
rds_inc_init(&recv->r_ibinc->ii_inc, conn, conn->c_faddr);
}
......
......@@ -143,15 +143,16 @@ static int rds_iw_recv_refill_one(struct rds_connection *conn,
int ret = -ENOMEM;
if (recv->r_iwinc == NULL) {
if (atomic_read(&rds_iw_allocation) >= rds_iw_sysctl_max_recv_allocation) {
if (!atomic_add_unless(&rds_iw_allocation, 1, rds_iw_sysctl_max_recv_allocation)) {
rds_iw_stats_inc(s_iw_rx_alloc_limit);
goto out;
}
recv->r_iwinc = kmem_cache_alloc(rds_iw_incoming_slab,
kptr_gfp);
if (recv->r_iwinc == NULL)
if (recv->r_iwinc == NULL) {
atomic_dec(&rds_iw_allocation);
goto out;
atomic_inc(&rds_iw_allocation);
}
INIT_LIST_HEAD(&recv->r_iwinc->ii_frags);
rds_inc_init(&recv->r_iwinc->ii_inc, conn, conn->c_faddr);
}
......
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