kernel/linux.git, branch v3.4.109

Linux 3.4.109

2015-09-18T01:20:47+00:00

udp: fix behavior of wrong checksums

2015-09-18T01:20:47+00:00

commit beb39db59d14990e401e235faf66a6b9b31240b0 upstream. We have two problems in UDP stack related to bogus checksums : 1) We return -EAGAIN to application even if receive queue is not empty. This breaks applications using edge trigger epoll() 2) Under UDP flood, we can loop forever without yielding to other processes, potentially hanging the host, especially on non SMP. This patch is an attempt to make things better. We might in the future add extra support for rt applications wanting to better control time spent doing a recv() in a hostile environment. For example we could validate checksums before queuing packets in socket receive queue. Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Zefan Li

sched: Queue RT tasks to head when prio drops

2015-09-18T01:20:47+00:00

commit 81a44c5441d7f7d2c3dc9105f4d65ad0d5818617 upstream. The following scenario does not work correctly: Runqueue of CPUx contains two runnable and pinned tasks: T1: SCHED_FIFO, prio 80 T2: SCHED_FIFO, prio 80 T1 is on the cpu and executes the following syscalls (classic priority ceiling scenario): sys_sched_setscheduler(pid(T1), SCHED_FIFO, .prio = 90); ... sys_sched_setscheduler(pid(T1), SCHED_FIFO, .prio = 80); ... Now T1 gets preempted by T3 (SCHED_FIFO, prio 95). After T3 goes back to sleep the scheduler picks T2. Surprise! The same happens w/o actual preemption when T1 is forced into the scheduler due to a sporadic NEED_RESCHED event. The scheduler invokes pick_next_task() which returns T2. So T1 gets preempted and scheduled out. This happens because sched_setscheduler() dequeues T1 from the prio 90 list and then enqueues it on the tail of the prio 80 list behind T2. This violates the POSIX spec and surprises user space which relies on the guarantee that SCHED_FIFO tasks are not scheduled out unless they give the CPU up voluntarily or are preempted by a higher priority task. In the latter case the preempted task must get back on the CPU after the preempting task schedules out again. We fixed a similar issue already in commit 60db48c (sched: Queue a deboosted task to the head of the RT prio queue). The same treatment is necessary for sched_setscheduler(). So enqueue to head of the prio bucket list if the priority of the task is lowered. It might be possible that existing user space relies on the current behaviour, but it can be considered highly unlikely due to the corner case nature of the application scenario. Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1391803122-4425-6-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar Signed-off-by: Zefan Li

pipe: iovec: Fix memory corruption when retrying atomic copy as non-atomic

2015-09-18T01:20:47+00:00

pipe_iov_copy_{from,to}_user() may be tried twice with the same iovec, the first time atomically and the second time not. The second attempt needs to continue from the iovec position, pipe buffer offset and remaining length where the first attempt failed, but currently the pipe buffer offset and remaining length are reset. This will corrupt the piped data (possibly also leading to an information leak between processes) and may also corrupt kernel memory. This was fixed upstream by commits f0d1bec9d58d ("new helper: copy_page_from_iter()") and 637b58c2887e ("switch pipe_read() to copy_page_to_iter()"), but those aren't suitable for stable. This fix for older kernel versions was made by Seth Jennings for RHEL and I have extracted it from their update. CVE-2015-1805 References: https://bugzilla.redhat.com/show_bug.cgi?id=1202855 Signed-off-by: Ben Hutchings [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li

NET: ROSE: Don't dereference NULL neighbour pointer.

2015-09-18T01:20:47+00:00

commit d496f7842aada20c61e6044b3395383fa972872c upstream. A ROSE socket doesn't necessarily always have a neighbour pointer so check if the neighbour pointer is valid before dereferencing it. Signed-off-by: Ralf Baechle Tested-by: Bernard Pidoux Signed-off-by: David S. Miller Signed-off-by: Zefan Li

block: fix ext_dev_lock lockdep report

2015-09-18T01:20:46+00:00

commit 4d66e5e9b6d720d8463e11d027bd4ad91c8b1318 upstream. ================================= [ INFO: inconsistent lock state ] 4.1.0-rc7+ #217 Tainted: G O --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/6/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (ext_devt_lock){+.?...}, at: [] blk_free_devt+0x3c/0x70 {SOFTIRQ-ON-W} state was registered at: [] __lock_acquire+0x461/0x1e70 [] lock_acquire+0xb7/0x290 [] _raw_spin_lock+0x38/0x50 [] blk_alloc_devt+0x6d/0xd0 <-- take the lock in process context [..] [] __lock_acquire+0x3fe/0x1e70 [] ? __lock_acquire+0xe5d/0x1e70 [] lock_acquire+0xb7/0x290 [] ? blk_free_devt+0x3c/0x70 [] _raw_spin_lock+0x38/0x50 [] ? blk_free_devt+0x3c/0x70 [] blk_free_devt+0x3c/0x70 <-- take the lock in softirq [] part_release+0x1c/0x50 [] device_release+0x36/0xb0 [] kobject_cleanup+0x7b/0x1a0 [] kobject_put+0x30/0x70 [] put_device+0x17/0x20 [] delete_partition_rcu_cb+0x16c/0x180 [] ? read_dev_sector+0xa0/0xa0 [] rcu_process_callbacks+0x2ff/0xa90 [] ? rcu_process_callbacks+0x2bf/0xa90 [] __do_softirq+0xde/0x600 Neil sees this in his tests and it also triggers on pmem driver unbind for the libnvdimm tests. This fix is on top of an initial fix by Keith for incorrect usage of mutex_lock() in this path: 2da78092dda1 "block: Fix dev_t minor allocation lifetime". Both this and 2da78092dda1 are candidates for -stable. Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime") Cc: Keith Busch Reported-by: NeilBrown Signed-off-by: Dan Williams Signed-off-by: Jens Axboe [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li

bridge: superfluous skb->nfct check in br_nf_dev_queue_xmit

2015-09-18T01:20:46+00:00

commit aff09ce303f83bd370772349238482ae422a2341 upstream. Currently bridge can silently drop ipv4 fragments. If node have loaded nf_defrag_ipv4 module but have no nf_conntrack_ipv4, br_nf_pre_routing defragments incoming ipv4 fragments but nfct check in br_nf_dev_queue_xmit does not allow re-fragment combined packet back, and therefore it is dropped in br_dev_queue_push_xmit without incrementing of any failcounters It seems the only way to hit the ip_fragment code in the bridge xmit path is to have a fragment list whose reassembled fragments go over the mtu. This only happens if nf_defrag is enabled. Thanks to Florian Westphal for providing feedback to clarify this. Defragmentation ipv4 is required not only in conntracks but at least in TPROXY target and socket match, therefore #ifdef is changed from NF_CONNTRACK_IPV4 to NF_DEFRAG_IPV4 Signed-off-by: Vasily Averin Signed-off-by: Pablo Neira Ayuso Cc: Kirill Tkhai Signed-off-by: Zefan Li

net: socket: Fix the wrong returns for recvmsg and sendmsg

2015-09-18T01:20:46+00:00

Based on 08adb7dabd4874cc5666b4490653b26534702ce0 upstream. We found that after v3.10.73, recvmsg might return -EFAULT while -EINVAL was expected. We tested it through the recvmsg01 testcase come from LTP testsuit. It set msg->msg_namelen to -1 and the recvmsg syscall returned errno 14, which is unexpected (errno 22 is expected): recvmsg01 4 TFAIL : invalid socket length ; returned -1 (expected -1), errno 14 (expected 22) Linux mainline has no this bug for commit 08adb7dab fixes it accidentally. However, it is too large and complex to be backported to LTS 3.10. Commit 281c9c36 (net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour) made get_compat_msghdr() return error if msg_sys->msg_namelen was negative, which changed the behaviors of recvmsg and sendmsg syscall in a lib32 system: Before commit 281c9c36, get_compat_msghdr() wouldn't fail and it would return -EINVAL in move_addr_to_user() or somewhere if msg_sys->msg_namelen was invalid and then syscall returned -EINVAL, which is correct. And now, when msg_sys->msg_namelen is negative, get_compat_msghdr() will fail and wants to return -EINVAL, however, the outer syscall will return -EFAULT directly, which is unexpected. This patch gets the return value of get_compat_msghdr() as well as copy_msghdr_from_user(), then returns this expected value if get_compat_msghdr() fails. Fixes: 281c9c36 (net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour) Signed-off-by: Junling Zheng Signed-off-by: Hanbing Xu Cc: Li Zefan Cc: Al Viro Cc: David Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Zefan Li

ipmi: fix timeout calculation when bmc is disconnected

2015-09-18T01:20:46+00:00

commit e21404dc0ac7ac971c1e36274b48bb460463f4e5 upstream. Loading ipmi_si module while bmc is disconnected, we found the timeout is longer than 5 secs. Actually it takes about 3 mins and 20 secs.(HZ=250) error message as below: Dec 12 19:08:59 linux kernel: IPMI BT: timeout in RD_WAIT [ ] 1 retries left Dec 12 19:08:59 linux kernel: BT: write 4 bytes seq=0x01 03 18 00 01 [...] Dec 12 19:12:19 linux kernel: IPMI BT: timeout in RD_WAIT [ ] Dec 12 19:12:19 linux kernel: failed 2 retries, sending error response Dec 12 19:12:19 linux kernel: IPMI: BT reset (takes 5 secs) Dec 12 19:12:19 linux kernel: IPMI BT: flag reset [ ] Function wait_for_msg_done() use schedule_timeout_uninterruptible(1) to sleep 1 tick, so we should subtract jiffies_to_usecs(1) instead of 100 usecs from timeout. Reported-by: Hu Shiyuan Signed-off-by: Xie XiuQi Signed-off-by: Corey Minyard Signed-off-by: Linus Torvalds Signed-off-by: Zefan Li

x86, kvm: fix kvm's usage of kernel_fpu_begin/end()

2015-09-18T01:20:46+00:00

commit b1a74bf8212367be2b1d6685c11a84e056eaaaf1 upstream. Preemption is disabled between kernel_fpu_begin/end() and as such it is not a good idea to use these routines in kvm_load/put_guest_fpu() which can be very far apart. kvm_load/put_guest_fpu() routines are already called with preemption disabled and KVM already uses the preempt notifier to save the guest fpu state using kvm_put_guest_fpu(). So introduce __kernel_fpu_begin/end() routines which don't touch preemption and use them instead of kernel_fpu_begin/end() for KVM's use model of saving/restoring guest FPU state. Also with this change (and with eagerFPU model), fix the host cr0.TS vm-exit state in the case of VMX. For eagerFPU case, host cr0.TS is always clear. So no need to worry about it. For the traditional lazyFPU restore case, change the cr0.TS bit for the host state during vm-exit to be always clear and cr0.TS bit is set in the __vmx_load_host_state() when the FPU (guest FPU or the host task's FPU) state is not active. This ensures that the host/guest FPU state is properly saved, restored during context-switch and with interrupts (using irq_fpu_usable()) not stomping on the active FPU state. Signed-off-by: Suresh Siddha Link: http://lkml.kernel.org/r/1348164109.26695.338.camel@sbsiddha-desk.sc.intel.com Cc: Avi Kivity Signed-off-by: H. Peter Anvin Signed-off-by: Zefan Li [xr: Backported to 3.4: Adjust context] Signed-off-by: Rui Xiang Signed-off-by: Zefan Li