linux/net/core, branch v2.6.28.1

netpoll: fix race on poll_list resulting in garbage entry

2008-12-10T07:22:26Z

A few months back a race was discused between the netpoll napi service path, and the fast path through net_rx_action: http://kerneltrap.org/mailarchive/linux-netdev/2007/10/16/345470 A patch was submitted for that bug, but I think we missed a case. Consider the following scenario: INITIAL STATE CPU0 has one napi_struct A on its poll_list CPU1 is calling netpoll_send_skb and needs to call poll_napi on the same napi_struct A that CPU0 has on its list CPU0 CPU1 net_rx_action poll_napi !list_empty (returns true) locks poll_lock for A poll_one_napi napi->poll netif_rx_complete __napi_complete (removes A from poll_list) list_entry(list->next) In the above scenario, net_rx_action assumes that the per-cpu poll_list is exclusive to that cpu. netpoll of course violates that, and because the netpoll path can dequeue from the poll list, its possible for CPU0 to detect a non-empty list at the top of the while loop in net_rx_action, but have it become empty by the time it calls list_entry. Since the poll_list isn't surrounded by any other structure, the returned data from that list_entry call in this situation is garbage, and any number of crashes can result based on what exactly that garbage is. Given that its not fasible for performance reasons to place exclusive locks arround each cpus poll list to provide that mutal exclusion, I think the best solution is modify the netpoll path in such a way that we continue to guarantee that the poll_list for a cpu is in fact exclusive to that cpu. To do this I've implemented the patch below. It adds an additional bit to the state field in the napi_struct. When executing napi->poll from the netpoll_path, this bit will be set. When a driver calls netif_rx_complete, if that bit is set, it will not remove the napi_struct from the poll_list. That work will be saved for the next iteration of net_rx_action. I've tested this and it seems to work well. About the biggest drawback I can see to it is the fact that it might result in an extra loop through net_rx_action in the event that the device is actually contended for (i.e. the netpoll path actually preforms all the needed work no the device, and the call to net_rx_action winds up doing nothing, except removing the napi_struct from the poll_list. However I think this is probably a small price to pay, given that the alternative is a crash. Signed-off-by: Neil Horman Signed-off-by: David S. Miller

net: make skb_truesize_bug() call WARN()

2008-11-26T05:08:13Z

The truesize message check is important enough to make it print "BUG" to the user console... lets also make it important enough to spit a backtrace/module list etc so that kerneloops.org can track them. Signed-off-by: Arjan van de Ven Signed-off-by: David S. Miller

net: Fix memory leak in the proto_register function

2008-11-22T00:45:22Z

If the slub allocator is used, kmem_cache_create() may merge two or more kmem_cache's into one but the cache name pointer is not updated and kmem_cache_name() is no longer guaranteed to return the pointer passed to the former function. This patch stores the kmalloc'ed pointers in the corresponding request_sock_ops and timewait_sock_ops structures. Signed-off-by: Catalin Marinas Acked-by: Arnaldo Carvalho de Melo Reviewed-by: Christoph Lameter Signed-off-by: David S. Miller

pktgen: fix multiple queue warning

2008-11-19T22:09:47Z

As number of TX queues in unrelated to number of CPU's we remove this test and just make sure nxtq never gets exceeded. Signed-off-by: Robert Olsson Signed-off-by: David S. Miller

rtnetlink: propagate error from dev_change_flags in do_setlink()

2008-11-17T07:20:31Z

Unlike ifconfig, iproute doesn't report an error when setting an interface up fails: (example: put wireless network mac80211 interface into repeater mode with iwconfig but do not set a peer MAC address, it should fail with -ENOLINK) without patch: # ip link set wlan0 up ; echo $? 0 # with patch: # ip link set wlan0 up ; echo $? RTNETLINK answers: Link has been severed 2 # Propagate the return value from dev_change_flags() to fix this. Signed-off-by: Patrick McHardy Tested-by: Johannes Berg Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

scm: fix scm_fp_list->list initialization made in wrong place

2008-11-14T22:51:45Z

This is the next page of the scm recursion story (the commit f8d570a4 net: Fix recursive descent in __scm_destroy()). In function scm_fp_dup(), the INIT_LIST_HEAD(&fpl->list) of newly created fpl is done *before* the subsequent memcpy from the old structure and thus the freshly initialized list is overwritten. But that's OK, since this initialization is not required at all, since the fpl->list is list_add-ed at the destruction time in any case (and is unused in other code), so I propose to drop both initializations, rather than moving it after the memcpy. Please, correct me if I miss something significant. Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller

lockdep: include/linux/lockdep.h - fix warning in net/bluetooth/af_bluetooth.c

2008-11-14T07:19:10Z

fix this warning: net/bluetooth/af_bluetooth.c:60: warning: ‘bt_key_strings’ defined but not used net/bluetooth/af_bluetooth.c:71: warning: ‘bt_slock_key_strings’ defined but not used this is a lockdep macro problem in the !LOCKDEP case. We cannot convert it to an inline because the macro works on multiple types, but we can mark the parameter used. [ also clean up a misaligned tab in sock_lock_init_class_and_name() ] [ also remove #ifdefs from around af_family_clock_key strings - which were certainly added to get rid of the ugly build warnings. ] Signed-off-by: Ingo Molnar Signed-off-by: David S. Miller

net: fix setting of skb->tail in skb_recycle_check()

2008-11-11T05:45:05Z

Since skb_reset_tail_pointer() reads skb->data, we need to set skb->data before calling skb_reset_tail_pointer(). This was causing spurious skb_over_panic()s from skb_put() being called on a recycled skb that had its skb->tail set to beyond where it should have been. Bug report from Peter van Valderen . Signed-off-by: Lennert Buytenhek Signed-off-by: David S. Miller

net: Fix recursive descent in __scm_destroy().

2008-11-06T23:45:32Z

__scm_destroy() walks the list of file descriptors in the scm_fp_list pointed to by the scm_cookie argument. Those, in turn, can close sockets and invoke __scm_destroy() again. There is nothing which limits how deeply this can occur. The idea for how to fix this is from Linus. Basically, we do all of the fput()s at the top level by collecting all of the scm_fp_list objects hit by an fput(). Inside of the initial __scm_destroy() we keep running the list until it is empty. Signed-off-by: David S. Miller

net: fix packet socket delivery in rx irq handler

2008-11-04T22:49:57Z

The changes to deliver hardware accelerated VLAN packets to packet sockets (commit bc1d0411) caused a warning for non-NAPI drivers. The __vlan_hwaccel_rx() function is called directly from the drivers RX function, for non-NAPI drivers that means its still in RX IRQ context: [ 27.779463] ------------[ cut here ]------------ [ 27.779509] WARNING: at kernel/softirq.c:136 local_bh_enable+0x37/0x81() ... [ 27.782520] [] netif_nit_deliver+0x5b/0x75 [ 27.782590] [] __vlan_hwaccel_rx+0x79/0x162 [ 27.782664] [] atl1_intr+0x9a9/0xa7c [atl1] [ 27.782738] [] handle_IRQ_event+0x23/0x51 [ 27.782808] [] handle_edge_irq+0xc2/0x102 [ 27.782878] [] do_IRQ+0x4d/0x64 Split hardware accelerated VLAN reception into two parts to fix this: - __vlan_hwaccel_rx just stores the VLAN TCI and performs the VLAN device lookup, then calls netif_receive_skb()/netif_rx() - vlan_hwaccel_do_receive(), which is invoked by netif_receive_skb() in softirq context, performs the real reception and delivery to packet sockets. Reported-and-tested-by: Ramon Casellas Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller