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2016-07-01cgroup: bpf: Add bpf_skb_in_cgroup_protoMartin KaFai Lau
Adds a bpf helper, bpf_skb_in_cgroup, to decide if a skb->sk belongs to a descendant of a cgroup2. It is similar to the feature added in netfilter: commit c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match") The user is expected to populate a BPF_MAP_TYPE_CGROUP_ARRAY which will be used by the bpf_skb_in_cgroup. Modifications to the bpf verifier is to ensure BPF_MAP_TYPE_CGROUP_ARRAY and bpf_skb_in_cgroup() are always used together. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01cgroup: bpf: Add BPF_MAP_TYPE_CGROUP_ARRAYMartin KaFai Lau
Add a BPF_MAP_TYPE_CGROUP_ARRAY and its bpf_map_ops's implementations. To update an element, the caller is expected to obtain a cgroup2 backed fd by open(cgroup2_dir) and then update the array with that fd. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01cgroup: Add cgroup_get_from_fdMartin KaFai Lau
Add a helper function to get a cgroup2 from a fd. It will be stored in a bpf array (BPF_MAP_TYPE_CGROUP_ARRAY) which will be introduced in the later patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01bpf: refactor bpf_prog_get and type check into helperDaniel Borkmann
Since bpf_prog_get() and program type check is used in a couple of places, refactor this into a small helper function that we can make use of. Since the non RO prog->aux part is not used in performance critical paths and a program destruction via RCU is rather very unlikley when doing the put, we shouldn't have an issue just doing the bpf_prog_get() + prog->type != type check, but actually not taking the ref at all (due to being in fdget() / fdput() section of the bpf fd) is even cleaner and makes the diff smaller as well, so just go for that. Callsites are changed to make use of the new helper where possible. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-01bpf: generally move prog destruction to RCU deferralDaniel Borkmann
Jann Horn reported following analysis that could potentially result in a very hard to trigger (if not impossible) UAF race, to quote his event timeline: - Set up a process with threads T1, T2 and T3 - Let T1 set up a socket filter F1 that invokes another filter F2 through a BPF map [tail call] - Let T1 trigger the socket filter via a unix domain socket write, don't wait for completion - Let T2 call PERF_EVENT_IOC_SET_BPF with F2, don't wait for completion - Now T2 should be behind bpf_prog_get(), but before bpf_prog_put() - Let T3 close the file descriptor for F2, dropping the reference count of F2 to 2 - At this point, T1 should have looked up F2 from the map, but not finished executing it - Let T3 remove F2 from the BPF map, dropping the reference count of F2 to 1 - Now T2 should call bpf_prog_put() (wrong BPF program type), dropping the reference count of F2 to 0 and scheduling bpf_prog_free_deferred() via schedule_work() - At this point, the BPF program could be freed - BPF execution is still running in a freed BPF program While at PERF_EVENT_IOC_SET_BPF time it's only guaranteed that the perf event fd we're doing the syscall on doesn't disappear from underneath us for whole syscall time, it may not be the case for the bpf fd used as an argument only after we did the put. It needs to be a valid fd pointing to a BPF program at the time of the call to make the bpf_prog_get() and while T2 gets preempted, F2 must have dropped reference to 1 on the other CPU. The fput() from the close() in T3 should also add additionally delay to the reference drop via exit_task_work() when bpf_prog_release() gets called as well as scheduling bpf_prog_free_deferred(). That said, it makes nevertheless sense to move the BPF prog destruction generally after RCU grace period to guarantee that such scenario above, but also others as recently fixed in ceb56070359b ("bpf, perf: delay release of BPF prog after grace period") with regards to tail calls won't happen. Integrating bpf_prog_free_deferred() directly into the RCU callback is not allowed since the invocation might happen from either softirq or process context, so we're not permitted to block. Reviewing all bpf_prog_put() invocations from eBPF side (note, cBPF -> eBPF progs don't use this for their destruction) with call_rcu() look good to me. Since we don't know whether at the time of attaching the program, we're already part of a tail call map, we need to use RCU variant. However, due to this, there won't be severely more stress on the RCU callback queue: situations with above bpf_prog_get() and bpf_prog_put() combo in practice normally won't lead to releases, but even if they would, enough effort/ cycles have to be put into loading a BPF program into the kernel already. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30bpf: don't use raw processor id in generic helperDaniel Borkmann
Use smp_processor_id() for the generic helper bpf_get_smp_processor_id() instead of the raw variant. This allows for preemption checks when we have DEBUG_PREEMPT, and otherwise uses the raw variant anyway. We only need to keep the raw variant for socket filters, but we can reuse the helper that is already there from cBPF side. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30bpf, trace: add BPF_F_CURRENT_CPU flag for bpf_perf_event_readDaniel Borkmann
Follow-up commit to 1e33759c788c ("bpf, trace: add BPF_F_CURRENT_CPU flag for bpf_perf_event_output") to add the same functionality into bpf_perf_event_read() helper. The split of index into flags and index component is also safe here, since such large maps are rejected during map allocation time. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30bpf, trace: fetch current cpu only onceDaniel Borkmann
We currently have two invocations, which is unnecessary. Fetch it only once and use the smp_processor_id() variant, so we also get preemption checks along with it when DEBUG_PREEMPT is set. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30bpf: minor cleanups on fd maps and helpersDaniel Borkmann
Some minor cleanups: i) Remove the unlikely() from fd array map lookups and let the CPU branch predictor do its job, scenarios where there is not always a map entry are very well valid. ii) Move the attribute type check in the bpf_perf_event_read() helper a bit earlier so it's consistent wrt checks with bpf_perf_event_output() helper as well. iii) remove some comments that are self-documenting in kprobe_prog_is_valid_access() and therefore make it consistent to tp_prog_is_valid_access() as well. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Several cases of overlapping changes, except the packet scheduler conflicts which deal with the addition of the free list parameter to qdisc_enqueue(). Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-29Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/auditLinus Torvalds
Pull audit fixes from Paul Moore: "Two small patches to fix audit problems in 4.7-rcX: the first fixes a potential kref leak, the second removes some header file noise. The first is an important bug fix that really should go in before 4.7 is released, the second is not critical, but falls into the very-nice- to-have category so I'm including in the pull request. Both patches are straightforward, self-contained, and pass our testsuite without problem" * 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit: audit: move audit_get_tty to reduce scope and kabi changes audit: move calcs after alloc and check when logging set loginuid
2016-06-29Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: "I've been traveling so this accumulates more than week or so of bug fixing. It perhaps looks a little worse than it really is. 1) Fix deadlock in ath10k driver, from Ben Greear. 2) Increase scan timeout in iwlwifi, from Luca Coelho. 3) Unbreak STP by properly reinjecting STP packets back into the stack. Regression fix from Ido Schimmel. 4) Mediatek driver fixes (missing malloc failure checks, leaking of scratch memory, wrong indexing when mapping TX buffers, etc.) from John Crispin. 5) Fix endianness bug in icmpv6_err() handler, from Hannes Frederic Sowa. 6) Fix hashing of flows in UDP in the ruseport case, from Xuemin Su. 7) Fix netlink notifications in ovs for tunnels, delete link messages are never emitted because of how the device registry state is handled. From Nicolas Dichtel. 8) Conntrack module leaks kmemcache on unload, from Florian Westphal. 9) Prevent endless jump loops in nft rules, from Liping Zhang and Pablo Neira Ayuso. 10) Not early enough spinlock initialization in mlx4, from Eric Dumazet. 11) Bind refcount leak in act_ipt, from Cong WANG. 12) Missing RCU locking in HTB scheduler, from Florian Westphal. 13) Several small MACSEC bug fixes from Sabrina Dubroca (missing RCU barrier, using heap for SG and IV, and erroneous use of async flag when allocating AEAD conext.) 14) RCU handling fix in TIPC, from Ying Xue. 15) Pass correct protocol down into ipv4_{update_pmtu,redirect}() in SIT driver, from Simon Horman. 16) Socket timer deadlock fix in TIPC from Jon Paul Maloy. 17) Fix potential deadlock in team enslave, from Ido Schimmel. 18) Memory leak in KCM procfs handling, from Jiri Slaby. 19) ESN generation fix in ipv4 ESP, from Herbert Xu. 20) Fix GFP_KERNEL allocations with locks held in act_ife, from Cong WANG. 21) Use after free in netem, from Eric Dumazet. 22) Uninitialized last assert time in multicast router code, from Tom Goff. 23) Skip raw sockets in sock_diag destruction broadcast, from Willem de Bruijn. 24) Fix link status reporting in thunderx, from Sunil Goutham. 25) Limit resegmentation of retransmit queue so that we do not retransmit too large GSO frames. From Eric Dumazet. 26) Delay bpf program release after grace period, from Daniel Borkmann" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (141 commits) openvswitch: fix conntrack netlink event delivery qed: Protect the doorbell BAR with the write barriers. neigh: Explicitly declare RCU-bh read side critical section in neigh_xmit() e1000e: keep VLAN interfaces functional after rxvlan off cfg80211: fix proto in ieee80211_data_to_8023 for frames without LLC header qlcnic: use the correct ring in qlcnic_83xx_process_rcv_ring_diag() bpf, perf: delay release of BPF prog after grace period net: bridge: fix vlan stats continue counter tcp: do not send too big packets at retransmit time ibmvnic: fix to use list_for_each_safe() when delete items net: thunderx: Fix TL4 configuration for secondary Qsets net: thunderx: Fix link status reporting net/mlx5e: Reorganize ethtool statistics net/mlx5e: Fix number of PFC counters reported to ethtool net/mlx5e: Prevent adding the same vxlan port net/mlx5e: Check for BlueFlame capability before allocating SQ uar net/mlx5e: Change enum to better reflect usage net/mlx5: Add ConnectX-5 PCIe 4.0 to list of supported devices net/mlx5: Update command strings net: marvell: Add separate config ANEG function for Marvell 88E1111 ...
2016-06-29Merge branch 'for-4.7-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Three fix patches. Two are for cgroup / css init failure path. The last one makes css_set_lock irq-safe as the deadline scheduler ends up calling put_css_set() from irq context" * 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Disable IRQs while holding css_set_lock cgroup: set css->id to -1 during init cgroup: remove redundant cleanup in css_create
2016-06-29bpf, perf: delay release of BPF prog after grace periodDaniel Borkmann
Commit dead9f29ddcc ("perf: Fix race in BPF program unregister") moved destruction of BPF program from free_event_rcu() callback to __free_event(), which is problematic if used with tail calls: if prog A is attached as trace event directly, but at the same time present in a tail call map used by another trace event program elsewhere, then we need to delay destruction via RCU grace period since it can still be in use by the program doing the tail call (the prog first needs to be dropped from the tail call map, then trace event with prog A attached destroyed, so we get immediate destruction). Fixes: dead9f29ddcc ("perf: Fix race in BPF program unregister") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Jann Horn <jann@thejh.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-28audit: move audit_get_tty to reduce scope and kabi changesRichard Guy Briggs
The only users of audit_get_tty and audit_put_tty are internal to audit, so move it out of include/linux/audit.h to kernel.h and create a proper function rather than inlining it. This also reduces kABI changes. Suggested-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: line wrapped description] Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-28audit: move calcs after alloc and check when logging set loginuidRichard Guy Briggs
Move the calculations of values after the allocation in case the allocation fails. This avoids wasting effort in the rare case that it fails, but more importantly saves us extra logic to release the tty ref. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-25Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Thomas Gleixner: "A couple of scheduler fixes: - force watchdog reset while processing sysrq-w - fix a deadlock when enabling trace events in the scheduler - fixes to the throttled next buddy logic - fixes for the average accounting (missing serialization and underflow handling) - allow kernel threads for fallback to online but not active cpus" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Allow kthreads to fall back to online && !active cpus sched/fair: Do not announce throttled next buddy in dequeue_task_fair() sched/fair: Initialize throttle_count for new task-groups lazily sched/fair: Fix cfs_rq avg tracking underflow kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w sched/debug: Fix deadlock when enabling sched events sched/fair: Fix post_init_entity_util_avg() serialization
2016-06-25Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Thomas Gleixner: "A single fix to address a race in the static key logic" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/static_key: Fix concurrent static_key_slow_inc()
2016-06-25Fix build break in fork.c when THREAD_SIZE < PAGE_SIZEMichael Ellerman
Commit b235beea9e99 ("Clarify naming of thread info/stack allocators") breaks the build on some powerpc configs, where THREAD_SIZE < PAGE_SIZE: kernel/fork.c:235:2: error: implicit declaration of function 'free_thread_stack' kernel/fork.c:355:8: error: assignment from incompatible pointer type stack = alloc_thread_stack_node(tsk, node); ^ Fix it by renaming free_stack() to free_thread_stack(), and updating the return type of alloc_thread_stack_node(). Fixes: b235beea9e99 ("Clarify naming of thread info/stack allocators") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-25Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge misc fixes from Andrew Morton: "Two weeks worth of fixes here" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits) init/main.c: fix initcall_blacklisted on ia64, ppc64 and parisc64 autofs: don't get stuck in a loop if vfs_write() returns an error mm/page_owner: avoid null pointer dereference tools/vm/slabinfo: fix spelling mistake: "Ocurrences" -> "Occurrences" fs/nilfs2: fix potential underflow in call to crc32_le oom, suspend: fix oom_reaper vs. oom_killer_disable race ocfs2: disable BUG assertions in reading blocks mm, compaction: abort free scanner if split fails mm: prevent KASAN false positives in kmemleak mm/hugetlb: clear compound_mapcount when freeing gigantic pages mm/swap.c: flush lru pvecs on compound page arrival memcg: css_alloc should return an ERR_PTR value on error memcg: mem_cgroup_migrate() may be called with irq disabled hugetlb: fix nr_pmds accounting with shared page tables Revert "mm: disable fault around on emulated access bit architecture" Revert "mm: make faultaround produce old ptes" mailmap: add Boris Brezillon's email mailmap: add Antoine Tenart's email mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask mm: mempool: kasan: don't poot mempool objects in quarantine ...
2016-06-25oom, suspend: fix oom_reaper vs. oom_killer_disable raceMichal Hocko
Tetsuo has reported the following potential oom_killer_disable vs. oom_reaper race: (1) freeze_processes() starts freezing user space threads. (2) Somebody (maybe a kenrel thread) calls out_of_memory(). (3) The OOM killer calls mark_oom_victim() on a user space thread P1 which is already in __refrigerator(). (4) oom_killer_disable() sets oom_killer_disabled = true. (5) P1 leaves __refrigerator() and enters do_exit(). (6) The OOM reaper calls exit_oom_victim(P1) before P1 can call exit_oom_victim(P1). (7) oom_killer_disable() returns while P1 not yet finished (8) P1 perform IO/interfere with the freezer. This situation is unfortunate. We cannot move oom_killer_disable after all the freezable kernel threads are frozen because the oom victim might depend on some of those kthreads to make a forward progress to exit so we could deadlock. It is also far from trivial to teach the oom_reaper to not call exit_oom_victim() because then we would lose a guarantee of the OOM killer and oom_killer_disable forward progress because exit_mm->mmput might block and never call exit_oom_victim. It seems the easiest way forward is to workaround this race by calling try_to_freeze_tasks again after oom_killer_disable. This will make sure that all the tasks are frozen or it bails out. Fixes: 449d777d7ad6 ("mm, oom_reaper: clear TIF_MEMDIE for all tasks queued for oom_reaper") Link: http://lkml.kernel.org/r/1466597634-16199-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24Clarify naming of thread info/stack allocatorsLinus Torvalds
We've had the thread info allocated together with the thread stack for most architectures for a long time (since the thread_info was split off from the task struct), but that is about to change. But the patches that move the thread info to be off-stack (and a part of the task struct instead) made it clear how confused the allocator and freeing functions are. Because the common case was that we share an allocation with the thread stack and the thread_info, the two pointers were identical. That identity then meant that we would have things like ti = alloc_thread_info_node(tsk, node); ... tsk->stack = ti; which certainly _worked_ (since stack and thread_info have the same value), but is rather confusing: why are we assigning a thread_info to the stack? And if we move the thread_info away, the "confusing" code just gets to be entirely bogus. So remove all this confusion, and make it clear that we are doing the stack allocation by renaming and clarifying the function names to be about the stack. The fact that the thread_info then shares the allocation is an implementation detail, and not really about the allocation itself. This is a pure renaming and type fix: we pass in the same pointer, it's just that we clarify what the pointer means. The ia64 code that actually only has one single allocation (for all of task_struct, thread_info and kernel thread stack) now looks a bit odd, but since "tsk->stack" is actually not even used there, that oddity doesn't matter. It would be a separate thing to clean that up, I intentionally left the ia64 changes as a pure brute-force renaming and type change. Acked-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24sched/core: Allow kthreads to fall back to online && !active cpusTejun Heo
During CPU hotplug, CPU_ONLINE callbacks are run while the CPU is online but not active. A CPU_ONLINE callback may create or bind a kthread so that its cpus_allowed mask only allows the CPU which is being brought online. The kthread may start executing before the CPU is made active and can end up in select_fallback_rq(). In such cases, the expected behavior is selecting the CPU which is coming online; however, because select_fallback_rq() only chooses from active CPUs, it determines that the task doesn't have any viable CPU in its allowed mask and ends up overriding it to cpu_possible_mask. CPU_ONLINE callbacks should be able to put kthreads on the CPU which is coming online. Update select_fallback_rq() so that it follows cpu_online() rather than cpu_active() for kthreads. Reported-by: Gautham R Shenoy <ego@linux.vnet.ibm.com> Tested-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@fb.com Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20160616193504.GB3262@mtj.duckdns.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24sched/fair: Do not announce throttled next buddy in dequeue_task_fair()Konstantin Khlebnikov
Hierarchy could be already throttled at this point. Throttled next buddy could trigger a NULL pointer dereference in pick_next_task_fair(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24sched/fair: Initialize throttle_count for new task-groups lazilyKonstantin Khlebnikov
Cgroup created inside throttled group must inherit current throttle_count. Broken throttle_count allows to nominate throttled entries as a next buddy, later this leads to null pointer dereference in pick_next_task_fair(). This patch initialize cfs_rq->throttle_count at first enqueue: laziness allows to skip locking all rq at group creation. Lazy approach also allows to skip full sub-tree scan at throttling hierarchy (not in this patch). Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bsegall@google.com Link: http://lkml.kernel.org/r/146608182119.21870.8439834428248129633.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24locking/static_key: Fix concurrent static_key_slow_inc()Paolo Bonzini
The following scenario is possible: CPU 1 CPU 2 static_key_slow_inc() atomic_inc_not_zero() -> key.enabled == 0, no increment jump_label_lock() atomic_inc_return() -> key.enabled == 1 now static_key_slow_inc() atomic_inc_not_zero() -> key.enabled == 1, inc to 2 return ** static key is wrong! jump_label_update() jump_label_unlock() Testing the static key at the point marked by (**) will follow the wrong path for jumps that have not been patched yet. This can actually happen when creating many KVM virtual machines with userspace LAPIC emulation; just run several copies of the following program: #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/kvm.h> int main(void) { for (;;) { int kvmfd = open("/dev/kvm", O_RDONLY); int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0); close(ioctl(vmfd, KVM_CREATE_VCPU, 1)); close(vmfd); close(kvmfd); } return 0; } Every KVM_CREATE_VCPU ioctl will attempt a static_key_slow_inc() call. The static key's purpose is to skip NULL pointer checks and indeed one of the processes eventually dereferences NULL. As explained in the commit that introduced the bug: 706249c222f6 ("locking/static_keys: Rework update logic") jump_label_update() needs key.enabled to be true. The solution adopted here is to temporarily make key.enabled == -1, and use go down the slow path when key.enabled <= 0. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> # v4.3+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 706249c222f6 ("locking/static_keys: Rework update logic") Link: http://lkml.kernel.org/r/1466527937-69798-1-git-send-email-pbonzini@redhat.com [ Small stylistic edits to the changelog and the code. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-23cgroup: Disable IRQs while holding css_set_lockDaniel Bristot de Oliveira
While testing the deadline scheduler + cgroup setup I hit this warning. [ 132.612935] ------------[ cut here ]------------ [ 132.612951] WARNING: CPU: 5 PID: 0 at kernel/softirq.c:150 __local_bh_enable_ip+0x6b/0x80 [ 132.612952] Modules linked in: (a ton of modules...) [ 132.612981] CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.7.0-rc2 #2 [ 132.612981] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.2-20150714_191134- 04/01/2014 [ 132.612982] 0000000000000086 45c8bb5effdd088b ffff88013fd43da0 ffffffff813d229e [ 132.612984] 0000000000000000 0000000000000000 ffff88013fd43de0 ffffffff810a652b [ 132.612985] 00000096811387b5 0000000000000200 ffff8800bab29d80 ffff880034c54c00 [ 132.612986] Call Trace: [ 132.612987] <IRQ> [<ffffffff813d229e>] dump_stack+0x63/0x85 [ 132.612994] [<ffffffff810a652b>] __warn+0xcb/0xf0 [ 132.612997] [<ffffffff810e76a0>] ? push_dl_task.part.32+0x170/0x170 [ 132.612999] [<ffffffff810a665d>] warn_slowpath_null+0x1d/0x20 [ 132.613000] [<ffffffff810aba5b>] __local_bh_enable_ip+0x6b/0x80 [ 132.613008] [<ffffffff817d6c8a>] _raw_write_unlock_bh+0x1a/0x20 [ 132.613010] [<ffffffff817d6c9e>] _raw_spin_unlock_bh+0xe/0x10 [ 132.613015] [<ffffffff811388ac>] put_css_set+0x5c/0x60 [ 132.613016] [<ffffffff8113dc7f>] cgroup_free+0x7f/0xa0 [ 132.613017] [<ffffffff810a3912>] __put_task_struct+0x42/0x140 [ 132.613018] [<ffffffff810e776a>] dl_task_timer+0xca/0x250 [ 132.613027] [<ffffffff810e76a0>] ? push_dl_task.part.32+0x170/0x170 [ 132.613030] [<ffffffff8111371e>] __hrtimer_run_queues+0xee/0x270 [ 132.613031] [<ffffffff81113ec8>] hrtimer_interrupt+0xa8/0x190 [ 132.613034] [<ffffffff81051a58>] local_apic_timer_interrupt+0x38/0x60 [ 132.613035] [<ffffffff817d9b0d>] smp_apic_timer_interrupt+0x3d/0x50 [ 132.613037] [<ffffffff817d7c5c>] apic_timer_interrupt+0x8c/0xa0 [ 132.613038] <EOI> [<ffffffff81063466>] ? native_safe_halt+0x6/0x10 [ 132.613043] [<ffffffff81037a4e>] default_idle+0x1e/0xd0 [ 132.613044] [<ffffffff810381cf>] arch_cpu_idle+0xf/0x20 [ 132.613046] [<ffffffff810e8fda>] default_idle_call+0x2a/0x40 [ 132.613047] [<ffffffff810e92d7>] cpu_startup_entry+0x2e7/0x340 [ 132.613048] [<ffffffff81050235>] start_secondary+0x155/0x190 [ 132.613049] ---[ end trace f91934d162ce9977 ]--- The warn is the spin_(lock|unlock)_bh(&css_set_lock) in the interrupt context. Converting the spin_lock_bh to spin_lock_irq(save) to avoid this problem - and other problems of sharing a spinlock with an interrupt. Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: cgroups@vger.kernel.org Cc: stable@vger.kernel.org # 4.5+ Cc: linux-kernel@vger.kernel.org Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2016-06-23locking: avoid passing around 'thread_info' in mutex debugging codeLinus Torvalds
None of the code actually wants a thread_info, it all wants a task_struct, and it's just converting back and forth between the two ("ti->task" to get the task_struct from the thread_info, and "task_thread_info(task)" to go the other way). No semantic change. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-20Merge tag 'trace-v4.7-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Two fixes for the tracing system: - When trace_printk() is used with a non constant format descriptor, it adds a NULL pointer into the trace format section, and the code isn't prepared to deal with it. This bug appeared by a change that was added in v3.5. - The ftracetest (selftests section) can't handle testing histograms when histograms are not configured. Currently it shows that they fail the test, when they should state that they are unsupported. This bug was added in the 4.7 merge window with the addition of the historgram code" * tag 'trace-v4.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftracetest: Fix hist unsupported result in hist selftests tracing: Handle NULL formats in hold_module_trace_bprintk_format()
2016-06-20tracing: Handle NULL formats in hold_module_trace_bprintk_format()Steven Rostedt (Red Hat)
If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com Reported-by: xingzhen <zhengjun.xing@intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Fixes: 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-20sched/fair: Fix cfs_rq avg tracking underflowPeter Zijlstra
As per commit: b7fa30c9cc48 ("sched/fair: Fix post_init_entity_util_avg() serialization") > the code generated from update_cfs_rq_load_avg(): > > if (atomic_long_read(&cfs_rq->removed_load_avg)) { > s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); > sa->load_avg = max_t(long, sa->load_avg - r, 0); > sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0); > removed_load = 1; > } > > turns into: > > ffffffff81087064: 49 8b 85 98 00 00 00 mov 0x98(%r13),%rax > ffffffff8108706b: 48 85 c0 test %rax,%rax > ffffffff8108706e: 74 40 je ffffffff810870b0 <update_blocked_averages+0xc0> > ffffffff81087070: 4c 89 f8 mov %r15,%rax > ffffffff81087073: 49 87 85 98 00 00 00 xchg %rax,0x98(%r13) > ffffffff8108707a: 49 29 45 70 sub %rax,0x70(%r13) > ffffffff8108707e: 4c 89 f9 mov %r15,%rcx > ffffffff81087081: bb 01 00 00 00 mov $0x1,%ebx > ffffffff81087086: 49 83 7d 70 00 cmpq $0x0,0x70(%r13) > ffffffff8108708b: 49 0f 49 4d 70 cmovns 0x70(%r13),%rcx > > Which you'll note ends up with sa->load_avg -= r in memory at > ffffffff8108707a. So I _should_ have looked at other unserialized users of ->load_avg, but alas. Luckily nikbor reported a similar /0 from task_h_load() which instantly triggered recollection of this here problem. Aside from the intermediate value hitting memory and causing problems, there's another problem: the underflow detection relies on the signed bit. This reduces the effective width of the variables, IOW its effectively the same as having these variables be of signed type. This patch changes to a different means of unsigned underflow detection to not rely on the signed bit. This allows the variables to use the 'full' unsigned range. And it does so with explicit LOAD - STORE to ensure any intermediate value will never be visible in memory, allowing these unserialized loads. Note: GCC generates crap code for this, might warrant a look later. Note2: I say 'full' above, if we end up at U*_MAX we'll still explode; maybe we should do clamping on add too. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yuyang Du <yuyang.du@intel.com> Cc: bsegall@google.com Cc: kernel@kyup.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: steve.muckle@linaro.org Fixes: 9d89c257dfb9 ("sched/fair: Rewrite runnable load and utilization average tracking") Link: http://lkml.kernel.org/r/20160617091948.GJ30927@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16cgroup: set css->id to -1 during initTejun Heo
If percpu_ref initialization fails during css_create(), the free path can end up trying to free css->id of zero. As ID 0 is unused, it doesn't cause a critical breakage but it does trigger a warning message. Fix it by setting css->id to -1 from init_and_link_css(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Wenwei Tao <ww.tao0320@gmail.com> Fixes: 01e586598b22 ("cgroup: release css->id after css_free") Cc: stable@vger.kernel.org # v4.0+ Signed-off-by: Tejun Heo <tj@kernel.org>
2016-06-16bpf, maps: flush own entries on perf map releaseDaniel Borkmann
The behavior of perf event arrays are quite different from all others as they are tightly coupled to perf event fds, f.e. shown recently by commit e03e7ee34fdd ("perf/bpf: Convert perf_event_array to use struct file") to make refcounting on perf event more robust. A remaining issue that the current code still has is that since additions to the perf event array take a reference on the struct file via perf_event_get() and are only released via fput() (that cleans up the perf event eventually via perf_event_release_kernel()) when the element is either manually removed from the map from user space or automatically when the last reference on the perf event map is dropped. However, this leads us to dangling struct file's when the map gets pinned after the application owning the perf event descriptor exits, and since the struct file reference will in such case only be manually dropped or via pinned file removal, it leads to the perf event living longer than necessary, consuming needlessly resources for that time. Relations between perf event fds and bpf perf event map fds can be rather complex. F.e. maps can act as demuxers among different perf event fds that can possibly be owned by different threads and based on the index selection from the program, events get dispatched to one of the per-cpu fd endpoints. One perf event fd (or, rather a per-cpu set of them) can also live in multiple perf event maps at the same time, listening for events. Also, another requirement is that perf event fds can get closed from application side after they have been attached to the perf event map, so that on exit perf event map will take care of dropping their references eventually. Likewise, when such maps are pinned, the intended behavior is that a user application does bpf_obj_get(), puts its fds in there and on exit when fd is released, they are dropped from the map again, so the map acts rather as connector endpoint. This also makes perf event maps inherently different from program arrays as described in more detail in commit c9da161c6517 ("bpf: fix clearing on persistent program array maps"). To tackle this, map entries are marked by the map struct file that added the element to the map. And when the last reference to that map struct file is released from user space, then the tracked entries are purged from the map. This is okay, because new map struct files instances resp. frontends to the anon inode are provided via bpf_map_new_fd() that is called when we invoke bpf_obj_get_user() for retrieving a pinned map, but also when an initial instance is created via map_create(). The rest is resolved by the vfs layer automatically for us by keeping reference count on the map's struct file. Any concurrent updates on the map slot are fine as well, it just means that perf_event_fd_array_release() needs to delete less of its own entires. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-16bpf, maps: extend map_fd_get_ptr argumentsDaniel Borkmann
This patch extends map_fd_get_ptr() callback that is used by fd array maps, so that struct file pointer from the related map can be passed in. It's safe to remove map_update_elem() callback for the two maps since this is only allowed from syscall side, but not from eBPF programs for these two map types. Like in per-cpu map case, bpf_fd_array_map_update_elem() needs to be called directly here due to the extra argument. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-16bpf, maps: add release callbackDaniel Borkmann
Add a release callback for maps that is invoked when the last reference to its struct file is gone and the struct file about to be released by vfs. The handler will be used by fd array maps. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-16bpf, trace: check event type in bpf_perf_event_readAlexei Starovoitov
similar to bpf_perf_event_output() the bpf_perf_event_read() helper needs to check the type of the perf_event before reading the counter. Fixes: a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") Reported-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-16bpf: fix matching of data/data_end in verifierAlexei Starovoitov
The ctx structure passed into bpf programs is different depending on bpf program type. The verifier incorrectly marked ctx->data and ctx->data_end access based on ctx offset only. That caused loads in tracing programs int bpf_prog(struct pt_regs *ctx) { .. ctx->ax .. } to be incorrectly marked as PTR_TO_PACKET which later caused verifier to reject the program that was actually valid in tracing context. Fix this by doing program type specific matching of ctx offsets. Fixes: 969bf05eb3ce ("bpf: direct packet access") Reported-by: Sasha Goldshtein <goldshtn@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15kernel/kcov: unproxify debugfs file's fopsNicolai Stange
Since commit 49d200deaa68 ("debugfs: prevent access to removed files' private data"), a debugfs file's file_operations methods get proxied through lifetime aware wrappers. However, only a certain subset of the file_operations members is supported by debugfs and ->mmap isn't among them -- it appears to be NULL from the VFS layer's perspective. This behaviour breaks the /sys/kernel/debug/kcov file introduced concurrently with commit 5c9a8750a640 ("kernel: add kcov code coverage"). Since that file never gets removed, there is no file removal race and thus, a lifetime checking proxy isn't needed. Avoid the proxying for /sys/kernel/debug/kcov by creating it via debugfs_create_file_unsafe() rather than debugfs_create_file(). Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Fixes: 5c9a8750a640 ("kernel: add kcov code coverage") Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-14kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while ↵Andrey Ryabinin
processing sysrq-w Lengthy output of sysrq-w may take a lot of time on slow serial console. Currently we reset NMI-watchdog on the current CPU to avoid spurious lockup messages. Sometimes this doesn't work since softlockup watchdog might trigger on another CPU which is waiting for an IPI to proceed. We reset softlockup watchdogs on all CPUs, but we do this only after listing all tasks, and this may be too late on a busy system. So, reset watchdogs CPUs earlier, in for_each_process_thread() loop. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14sched/debug: Fix deadlock when enabling sched eventsJosh Poimboeuf
I see a hang when enabling sched events: echo 1 > /sys/kernel/debug/tracing/events/sched/enable The printk buffer shows: BUG: spinlock recursion on CPU#1, swapper/1/0 lock: 0xffff88007d5d8c00, .magic: dead4ead, .owner: swapper/1/0, .owner_cpu: 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc2+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014 ... Call Trace: <IRQ> [<ffffffff8143d663>] dump_stack+0x85/0xc2 [<ffffffff81115948>] spin_dump+0x78/0xc0 [<ffffffff81115aea>] do_raw_spin_lock+0x11a/0x150 [<ffffffff81891471>] _raw_spin_lock+0x61/0x80 [<ffffffff810e5466>] ? try_to_wake_up+0x256/0x4e0 [<ffffffff810e5466>] try_to_wake_up+0x256/0x4e0 [<ffffffff81891a0a>] ? _raw_spin_unlock_irqrestore+0x4a/0x80 [<ffffffff810e5705>] wake_up_process+0x15/0x20 [<ffffffff810cebb4>] insert_work+0x84/0xc0 [<ffffffff810ced7f>] __queue_work+0x18f/0x660 [<ffffffff810cf9a6>] queue_work_on+0x46/0x90 [<ffffffffa00cd95b>] drm_fb_helper_dirty.isra.11+0xcb/0xe0 [drm_kms_helper] [<ffffffffa00cdac0>] drm_fb_helper_sys_imageblit+0x30/0x40 [drm_kms_helper] [<ffffffff814babcd>] soft_cursor+0x1ad/0x230 [<ffffffff814ba379>] bit_cursor+0x649/0x680 [<ffffffff814b9d30>] ? update_attr.isra.2+0x90/0x90 [<ffffffff814b5e6a>] fbcon_cursor+0x14a/0x1c0 [<ffffffff81555ef8>] hide_cursor+0x28/0x90 [<ffffffff81558b6f>] vt_console_print+0x3bf/0x3f0 [<ffffffff81122c63>] call_console_drivers.constprop.24+0x183/0x200 [<ffffffff811241f4>] console_unlock+0x3d4/0x610 [<ffffffff811247f5>] vprintk_emit+0x3c5/0x610 [<ffffffff81124bc9>] vprintk_default+0x29/0x40 [<ffffffff811e965b>] printk+0x57/0x73 [<ffffffff810f7a9e>] enqueue_entity+0xc2e/0xc70 [<ffffffff810f7b39>] enqueue_task_fair+0x59/0xab0 [<ffffffff8106dcd9>] ? kvm_sched_clock_read+0x9/0x20 [<ffffffff8103fb39>] ? sched_clock+0x9/0x10 [<ffffffff810e3fcc>] activate_task+0x5c/0xa0 [<ffffffff810e4514>] ttwu_do_activate+0x54/0xb0 [<ffffffff810e5cea>] sched_ttwu_pending+0x7a/0xb0 [<ffffffff810e5e51>] scheduler_ipi+0x61/0x170 [<ffffffff81059e7f>] smp_trace_reschedule_interrupt+0x4f/0x2a0 [<ffffffff81893ba6>] trace_reschedule_interrupt+0x96/0xa0 <EOI> [<ffffffff8106e0d6>] ? native_safe_halt+0x6/0x10 [<ffffffff8110fb1d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81040ac0>] default_idle+0x20/0x1a0 [<ffffffff8104147f>] arch_cpu_idle+0xf/0x20 [<ffffffff81102f8f>] default_idle_call+0x2f/0x50 [<ffffffff8110332e>] cpu_startup_entry+0x37e/0x450 [<ffffffff8105af70>] start_secondary+0x160/0x1a0 Note the hang only occurs when echoing the above from a physical serial console, not from an ssh session. The bug is caused by a deadlock where the task is trying to grab the rq lock twice because printk()'s aren't safe in sched code. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: cb2517653fcc ("sched/debug: Make schedstats a runtime tunable that is disabled by default") Link: http://lkml.kernel.org/r/20160613073209.gdvdybiruljbkn3p@treble Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14sched/fair: Fix post_init_entity_util_avg() serializationPeter Zijlstra
Chris Wilson reported a divide by 0 at: post_init_entity_util_avg(): > 725 if (cfs_rq->avg.util_avg != 0) { > 726 sa->util_avg = cfs_rq->avg.util_avg * se->load.weight; > -> 727 sa->util_avg /= (cfs_rq->avg.load_avg + 1); > 728 > 729 if (sa->util_avg > cap) > 730 sa->util_avg = cap; > 731 } else { Which given the lack of serialization, and the code generated from update_cfs_rq_load_avg() is entirely possible: if (atomic_long_read(&cfs_rq->removed_load_avg)) { s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); sa->load_avg = max_t(long, sa->load_avg - r, 0); sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0); removed_load = 1; } turns into: ffffffff81087064: 49 8b 85 98 00 00 00 mov 0x98(%r13),%rax ffffffff8108706b: 48 85 c0 test %rax,%rax ffffffff8108706e: 74 40 je ffffffff810870b0 ffffffff81087070: 4c 89 f8 mov %r15,%rax ffffffff81087073: 49 87 85 98 00 00 00 xchg %rax,0x98(%r13) ffffffff8108707a: 49 29 45 70 sub %rax,0x70(%r13) ffffffff8108707e: 4c 89 f9 mov %r15,%rcx ffffffff81087081: bb 01 00 00 00 mov $0x1,%ebx ffffffff81087086: 49 83 7d 70 00 cmpq $0x0,0x70(%r13) ffffffff8108708b: 49 0f 49 4d 70 cmovns 0x70(%r13),%rcx Which you'll note ends up with 'sa->load_avg - r' in memory at ffffffff8108707a. By calling post_init_entity_util_avg() under rq->lock we're sure to be fully serialized against PELT updates and cannot observe intermediate state like this. Reported-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yuyang Du <yuyang.du@intel.com> Cc: bsegall@google.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: steve.muckle@linaro.org Fixes: 2b8c41daba32 ("sched/fair: Initiate a new task's util avg to a bounded value") Link: http://lkml.kernel.org/r/20160609130750.GQ30909@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-10Merge branch 'stacking-fixes' (vfs stacking fixes from Jann)Linus Torvalds
Merge filesystem stacking fixes from Jann Horn. * emailed patches from Jann Horn <jannh@google.com>: sched: panic on corrupted stack end ecryptfs: forbid opening files without mmap handler proc: prevent stacking filesystems on top
2016-06-10sched: panic on corrupted stack endJann Horn
Until now, hitting this BUG_ON caused a recursive oops (because oops handling involves do_exit(), which calls into the scheduler, which in turn raises an oops), which caused stuff below the stack to be overwritten until a panic happened (e.g. via an oops in interrupt context, caused by the overwritten CPU index in the thread_info). Just panic directly. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-10Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Two scheduler debugging fixes" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/debug: Fix 'schedstats=enable' cmdline option sched/debug: Fix /proc/sched_debug regression
2016-06-10Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "A handful of tooling fixes, two PMU driver fixes and a cleanup of redundant code that addresses a security analyzer false positive" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Remove a redundant check perf/x86/intel/uncore: Remove SBOX support for Broadwell server perf ctf: Convert invalid chars in a string before set value perf record: Fix crash when kptr is restricted perf symbols: Check kptr_restrict for root perf/x86/intel/rapl: Fix pmus free during cleanup
2016-06-10Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "Misc fixes: - a file-based futex fix - one more spin_unlock_wait() fix - a ww-mutex deadlock detection improvement/fix - and a raw_read_seqcount_latch() barrier fix" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Calculate the futex key based on a tail page for file-based futexes locking/qspinlock: Fix spin_unlock_wait() some more locking/ww_mutex: Report recursive ww_mutex locking early locking/seqcount: Re-fix raw_read_seqcount_latch()
2016-06-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) nfnetlink timestamp taken from wrong skb, fix from Florian Westphal. 2) Revert some msleep conversions in rtlwifi as these spots are in atomic context, from Larry Finger. 3) Validate that NFTA_SET_TABLE attribute is actually specified when we call nf_tables_getset(). From Phil Turnbull. 4) Don't do mdio_reset in stmmac driver with spinlock held as that can sleep, from Vincent Palatin. 5) sk_filter() does things other than run a BPF filter, so we should not elide it's call just because sk->sk_filter is NULL. Fix from Eric Dumazet. 6) Fix missing backlog updates in several packet schedulers, from Cong Wang. 7) bnx2x driver should allow VLAN add/remove while the interface is down, from Michal Schmidt. 8) Several RDS/TCP race fixes from Sowmini Varadhan. 9) fq_codel scheduler doesn't return correct queue length in dumps, from Eric Dumazet. 10) Fix TCP stats for tail loss probe and early retransmit in ipv6, from Yuchung Cheng. 11) Properly initialize udp_tunnel_socket_cfg in l2tp_tunnel_create(), from Guillaume Nault. 12) qfq scheduler leaks SKBs if a kzalloc fails, fix from Florian Westphal. 13) sock_fprog passed into PACKET_FANOUT_DATA needs compat handling, from Willem de Bruijn. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (85 commits) vmxnet3: segCnt can be 1 for LRO packets packet: compat support for sock_fprog stmmac: fix parameter to dwmac4_set_umac_addr() net/mlx5e: Fix blue flame quota logic net/mlx5e: Use ndo_stop explicitly at shutdown flow net/mlx5: E-Switch, always set mc_promisc for allmulti vports net/mlx5: E-Switch, Modify node guid on vf set MAC net/mlx5: E-Switch, Fix vport enable flow net/mlx5: E-Switch, Use the correct error check on returned pointers net/mlx5: E-Switch, Use the correct free() function net/mlx5: Fix E-Switch flow steering capabilities check net/mlx5: Fix flow steering NIC capabilities check net/mlx5: Fix root flow table update net/mlx5: Fix MLX5_CMD_OP_MAX to be defined correctly net/mlx5: Fix masking of reserved bits in XRCD number net/mlx5: Fix the size of modify QP mailbox mlxsw: spectrum: Don't sleep during ndo_get_phys_port_name() mlxsw: spectrum: Make split flow match firmware requirements wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel cfg80211: remove get/set antenna and tx power warnings ...
2016-06-10Merge tag 'pm-4.7-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "Stable-candidate fixes for the intel_pstate driver and the cpuidle core. Specifics: - Fix two intel_pstate initialization issues, one of which was introduced during the 4.4 cycle (Srinivas Pandruvada) - Fix kernel build with CONFIG_UBSAN set and CONFIG_CPU_IDLE unset (Catalin Marinas)" * tag 'pm-4.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpufreq: intel_pstate: Fix ->set_policy() interface for no_turbo cpufreq: intel_pstate: Fix code ordering in intel_pstate_set_policy() cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE
2016-06-09Merge branches 'pm-cpufreq-fixes' and 'pm-cpuidle'Rafael J. Wysocki
* pm-cpufreq-fixes: cpufreq: intel_pstate: Fix ->set_policy() interface for no_turbo cpufreq: intel_pstate: Fix code ordering in intel_pstate_set_policy() * pm-cpuidle: cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE
2016-06-09kernel/relay.c: fix potential memory leakZhouyi Zhou
When relay_open_buf() fails in relay_open(), code will goto free_bufs, but chan is nowhere freed. Link: http://lkml.kernel.org/r/1464777927-19675-1-git-send-email-yizhouzhou@ict.ac.cn Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>