BMC/Intel-BMC/linux.git/net/ipv4/inet_connection_sock.c, branch dev

inet: fix potential deadlock in reqsk_queue_unlink()

2015-08-14T05:46:22+00:00

When replacing del_timer() with del_timer_sync(), I introduced a deadlock condition : reqsk_queue_unlink() is called from inet_csk_reqsk_queue_drop() inet_csk_reqsk_queue_drop() can be called from many contexts, one being the timer handler itself (reqsk_timer_handler()). In this case, del_timer_sync() loops forever. Simple fix is to test if timer is pending. Fixes: 2235f2ac75fd ("inet: fix races with reqsk timers") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: fix races with reqsk timers

2015-08-11T04:17:29+00:00

reqsk_queue_destroy() and reqsk_queue_unlink() should use del_timer_sync() instead of del_timer() before calling reqsk_put(), otherwise we could free a req still used by another cpu. But before doing so, reqsk_queue_destroy() must release syn_wait_lock spinlock or risk a dead lock, as reqsk_timer_handler() might need to take this same spinlock from reqsk_queue_unlink() (called from inet_csk_reqsk_queue_drop()) Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: improve REUSEADDR/NOREUSEADDR cohabitation

2015-05-21T22:55:32+00:00

inet_csk_get_port() randomization effort tends to spread sockets on all the available range (ip_local_port_range) This is unfortunate because SO_REUSEADDR sockets have less requirements than non SO_REUSEADDR ones. If an application uses SO_REUSEADDR hint, it is to try to allow source ports being shared. So instead of picking a random port number in ip_local_port_range, lets try first in first half of the range. This gives more chances to use upper half of the range for the sockets with strong requirements (not using SO_REUSEADDR) Note this patch does not add a new sysctl, and only changes the way we try to pick port number. Signed-off-by: Eric Dumazet Cc: Marcelo Ricardo Leitner Cc: Flavio Leitner Acked-by: Flavio Leitner Signed-off-by: David S. Miller

inet_hashinfo: remove bsocket counter

2015-05-21T22:55:32+00:00

We no longer need bsocket atomic counter, as inet_csk_get_port() calls bind_conflict() regardless of its value, after commit 2b05ad33e1e624e ("tcp: bind() fix autoselection to share ports") This patch removes overhead of maintaining this counter and double inet_csk_get_port() calls under pressure. Signed-off-by: Eric Dumazet Cc: Marcelo Ricardo Leitner Cc: Flavio Leitner Acked-by: Flavio Leitner Signed-off-by: David S. Miller

inet: fix possible panic in reqsk_queue_unlink()

2015-04-24T15:39:15+00:00

[ 3897.923145] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 3897.931025] IP: [] reqsk_timer_handler+0x1a6/0x243 There is a race when reqsk_timer_handler() and tcp_check_req() call inet_csk_reqsk_queue_unlink() on the same req at the same time. Before commit fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer"), listener spinlock was held and race could not happen. To solve this bug, we change reqsk_queue_unlink() to not assume req must be found, and we return a status, to conditionally release a refcount on the request sock. This also means tcp_check_req() in non fastopen case might or not consume req refcount, so tcp_v6_hnd_req() & tcp_v4_hnd_req() have to properly handle this. (Same remark for dccp_check_req() and its callers) inet_csk_reqsk_queue_drop() is now too big to be inlined, as it is called 4 times in tcp and 3 times in dccp. Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer") Signed-off-by: Eric Dumazet Reported-by: Yuchung Cheng Signed-off-by: David S. Miller

ipv4: coding style: comparison for inequality with NULL

2015-04-03T16:11:15+00:00

The ipv4 code uses a mixture of coding styles. In some instances check for non-NULL pointer is done as x != NULL and sometimes as x. x is preferred according to checkpatch and this patch makes the code consistent by adopting the latter form. No changes detected by objdiff. Signed-off-by: Ian Morris Signed-off-by: David S. Miller

net: convert syn_wait_lock to a spinlock

2015-03-23T20:52:26+00:00

This is a low hanging fruit, as we'll get rid of syn_wait_lock eventually. We hold syn_wait_lock for such small sections, that it makes no sense to use a read/write lock. A spin lock is simply faster. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: remove some sk_listener dependencies

2015-03-23T20:52:26+00:00

listener can be source of false sharing. request sock has some useful information like : ireq->ir_iif, ireq->ir_num, ireq->ireq_net This patch does not solve the major problem of having to read sk->sk_protocol which is sharing a cache line with sk->sk_wmem_alloc. (This same field is read later in ip_build_and_send_pkt()) One idea would be to move sk_protocol close to sk_family (using 8 bits instead of 16 for sk_family seems enough) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: remove sk_listener parameter from syn_ack_timeout()

2015-03-23T20:52:25+00:00

It is not needed, and req->sk_listener points to the listener anyway. request_sock argument can be const. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: cache listen_sock_qlen() and read rskq_defer_accept once

2015-03-23T20:52:25+00:00

Cache listen_sock_qlen() to limit false sharing, and read rskq_defer_accept once as it might change under us. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller