user/sven/linux.git/kernel, branch v4.14.112

sched/fair: Do not re-read ->h_load_next during hierarchical load calculation

2019-04-17T06:37:54Z

commit 0e9f02450da07fc7b1346c8c32c771555173e397 upstream. A NULL pointer dereference bug was reported on a distribution kernel but the same issue should be present on mainline kernel. It occured on s390 but should not be arch-specific. A partial oops looks like: Unable to handle kernel pointer dereference in virtual kernel address space ... Call Trace: ... try_to_wake_up+0xfc/0x450 vhost_poll_wakeup+0x3a/0x50 [vhost] __wake_up_common+0xbc/0x178 __wake_up_common_lock+0x9e/0x160 __wake_up_sync_key+0x4e/0x60 sock_def_readable+0x5e/0x98 The bug hits any time between 1 hour to 3 days. The dereference occurs in update_cfs_rq_h_load when accumulating h_load. The problem is that cfq_rq->h_load_next is not protected by any locking and can be updated by parallel calls to task_h_load. Depending on the compiler, code may be generated that re-reads cfq_rq->h_load_next after the check for NULL and then oops when reading se->avg.load_avg. The dissassembly showed that it was possible to reread h_load_next after the check for NULL. While this does not appear to be an issue for later compilers, it's still an accident if the correct code is generated. Full locking in this path would have high overhead so this patch uses READ_ONCE to read h_load_next only once and check for NULL before dereferencing. It was confirmed that there were no further oops after 10 days of testing. As Peter pointed out, it is also necessary to use WRITE_ONCE() to avoid any potential problems with store tearing. Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Fixes: 685207963be9 ("sched: Move h_load calculation to task_h_load()") Link: https://lkml.kernel.org/r/20190319123610.nsivgf3mjbjjesxb@techsingularity.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

genirq: Initialize request_mutex if CONFIG_SPARSE_IRQ=n

2019-04-17T06:37:53Z

commit e8458e7afa855317b14915d7b86ab3caceea7eb6 upstream. When CONFIG_SPARSE_IRQ is disable, the request_mutex in struct irq_desc is not initialized which causes malfunction. Fixes: 9114014cf4e6 ("genirq: Add mutex to irq desc to serialize request/free_irq()") Signed-off-by: Kefeng Wang Signed-off-by: Thomas Gleixner Reviewed-by: Mukesh Ojha Cc: Marc Zyngier Cc: Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190404074512.145533-1-wangkefeng.wang@huawei.com Signed-off-by: Greg Kroah-Hartman

genirq: Respect IRQCHIP_SKIP_SET_WAKE in irq_chip_set_wake_parent()

2019-04-17T06:37:53Z

commit 325aa19598e410672175ed50982f902d4e3f31c5 upstream. If a child irqchip calls irq_chip_set_wake_parent() but its parent irqchip has the IRQCHIP_SKIP_SET_WAKE flag set an error is returned. This is inconsistent behaviour vs. set_irq_wake_real() which returns 0 when the irqchip has the IRQCHIP_SKIP_SET_WAKE flag set. It doesn't attempt to walk the chain of parents and set irq wake on any chips that don't have the flag set either. If the intent is to call the .irq_set_wake() callback of the parent irqchip, then we expect irqchip implementations to omit the IRQCHIP_SKIP_SET_WAKE flag and implement an .irq_set_wake() function that calls irq_chip_set_wake_parent(). The problem has been observed on a Qualcomm sdm845 device where set wake fails on any GPIO interrupts after applying work in progress wakeup irq patches to the GPIO driver. The chain of chips looks like this: QCOM GPIO -> QCOM PDC (SKIP) -> ARM GIC (SKIP) The GPIO controllers parent is the QCOM PDC irqchip which in turn has ARM GIC as parent. The QCOM PDC irqchip has the IRQCHIP_SKIP_SET_WAKE flag set, and so does the grandparent ARM GIC. The GPIO driver doesn't know if the parent needs to set wake or not, so it unconditionally calls irq_chip_set_wake_parent() causing this function to return a failure because the parent irqchip (PDC) doesn't have the .irq_set_wake() callback set. Returning 0 instead makes everything work and irqs from the GPIO controller can be configured for wakeup. Make it consistent by returning 0 (success) from irq_chip_set_wake_parent() when a parent chip has IRQCHIP_SKIP_SET_WAKE set. [ tglx: Massaged changelog ] Fixes: 08b55e2a9208e ("genirq: Add irqchip_set_wake_parent") Signed-off-by: Stephen Boyd Signed-off-by: Thomas Gleixner Acked-by: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org Cc: linux-gpio@vger.kernel.org Cc: Lina Iyer Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190325181026.247796-1-swboyd@chromium.org Signed-off-by: Greg Kroah-Hartman

alarmtimer: Return correct remaining time

2019-04-17T06:37:52Z

commit 07d7e12091f4ab869cc6a4bb276399057e73b0b3 upstream. To calculate a remaining time, it's required to subtract the current time from the expiration time. In alarm_timer_remaining() the arguments of ktime_sub are swapped. Fixes: d653d8457c76 ("alarmtimer: Implement remaining callback") Signed-off-by: Andrei Vagin Signed-off-by: Thomas Gleixner Reviewed-by: Mukesh Ojha Cc: Stephen Boyd Cc: John Stultz Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190408041542.26338-1-avagin@gmail.com Signed-off-by: Greg Kroah-Hartman

cpu/hotplug: Mute hotplug lockdep during init

2019-04-05T20:31:38Z

[ Upstream commit ce48c457b95316b9a01b5aa9d4456ce820df94b4 ] Since we've had: commit cb538267ea1e ("jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations") we've been getting some lockdep warnings during init, such as on HiKey960: [ 0.820495] WARNING: CPU: 4 PID: 0 at kernel/cpu.c:316 lockdep_assert_cpus_held+0x3c/0x48 [ 0.820498] Modules linked in: [ 0.820509] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G S 4.20.0-rc5-00051-g4cae42a #34 [ 0.820511] Hardware name: HiKey960 (DT) [ 0.820516] pstate: 600001c5 (nZCv dAIF -PAN -UAO) [ 0.820520] pc : lockdep_assert_cpus_held+0x3c/0x48 [ 0.820523] lr : lockdep_assert_cpus_held+0x38/0x48 [ 0.820526] sp : ffff00000a9cbe50 [ 0.820528] x29: ffff00000a9cbe50 x28: 0000000000000000 [ 0.820533] x27: 00008000b69e5000 x26: ffff8000bff4cfe0 [ 0.820537] x25: ffff000008ba69e0 x24: 0000000000000001 [ 0.820541] x23: ffff000008fce000 x22: ffff000008ba70c8 [ 0.820545] x21: 0000000000000001 x20: 0000000000000003 [ 0.820548] x19: ffff00000a35d628 x18: ffffffffffffffff [ 0.820552] x17: 0000000000000000 x16: 0000000000000000 [ 0.820556] x15: ffff00000958f848 x14: 455f3052464d4d34 [ 0.820559] x13: 00000000769dde98 x12: ffff8000bf3f65a8 [ 0.820564] x11: 0000000000000000 x10: ffff00000958f848 [ 0.820567] x9 : ffff000009592000 x8 : ffff00000958f848 [ 0.820571] x7 : ffff00000818ffa0 x6 : 0000000000000000 [ 0.820574] x5 : 0000000000000000 x4 : 0000000000000001 [ 0.820578] x3 : 0000000000000000 x2 : 0000000000000001 [ 0.820582] x1 : 00000000ffffffff x0 : 0000000000000000 [ 0.820587] Call trace: [ 0.820591] lockdep_assert_cpus_held+0x3c/0x48 [ 0.820598] static_key_enable_cpuslocked+0x28/0xd0 [ 0.820606] arch_timer_check_ool_workaround+0xe8/0x228 [ 0.820610] arch_timer_starting_cpu+0xe4/0x2d8 [ 0.820615] cpuhp_invoke_callback+0xe8/0xd08 [ 0.820619] notify_cpu_starting+0x80/0xb8 [ 0.820625] secondary_start_kernel+0x118/0x1d0 We've also had a similar warning in sched_init_smp() for every asymmetric system that would enable the sched_asym_cpucapacity static key, although that was singled out in: commit 40fa3780bac2 ("sched/core: Take the hotplug lock in sched_init_smp()") Those warnings are actually harmless, since we cannot have hotplug operations at the time they appear. Instead of starting to sprinkle useless hotplug lock operations in the init codepaths, mute the warnings until they start warning about real problems. Suggested-by: Peter Zijlstra Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Thomas Gleixner Cc: Will Deacon Cc: cai@gmx.us Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: linux-arm-kernel@lists.infradead.org Cc: longman@redhat.com Cc: marc.zyngier@arm.com Cc: mark.rutland@arm.com Link: https://lkml.kernel.org/r/1545243796-23224-2-git-send-email-valentin.schneider@arm.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

cgroup/pids: turn cgroup_subsys->free() into cgroup_subsys->release() to fix the accounting

2019-04-05T20:31:37Z

[ Upstream commit 51bee5abeab2058ea5813c5615d6197a23dbf041 ] The only user of cgroup_subsys->free() callback is pids_cgrp_subsys which needs pids_free() to uncharge the pid. However, ->free() is called from __put_task_struct()->cgroup_free() and this is too late. Even the trivial program which does for (;;) { int pid = fork(); assert(pid >= 0); if (pid) wait(NULL); else exit(0); } can run out of limits because release_task()->call_rcu(delayed_put_task_struct) implies an RCU gp after the task/pid goes away and before the final put(). Test-case: mkdir -p /tmp/CG mount -t cgroup2 none /tmp/CG echo '+pids' > /tmp/CG/cgroup.subtree_control mkdir /tmp/CG/PID echo 2 > /tmp/CG/PID/pids.max perl -e 'while ($p = fork) { wait; } $p // die "fork failed: $!\n"' & echo $! > /tmp/CG/PID/cgroup.procs Without this patch the forking process fails soon after migration. Rename cgroup_subsys->free() to cgroup_subsys->release() and move the callsite into the new helper, cgroup_release(), called by release_task() which actually frees the pid(s). Reported-by: Herton R. Krzesinski Reported-by: Jan Stancek Signed-off-by: Oleg Nesterov Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK

2019-04-05T20:31:36Z

[ Upstream commit 1ca4fa3ab604734e38e2a3000c9abf788512ffa7 ] register_sched_domain_sysctl() copies the cpu_possible_mask into sd_sysctl_cpus, but only if sd_sysctl_cpus hasn't already been allocated (ie, CONFIG_CPUMASK_OFFSTACK is set). However, when CONFIG_CPUMASK_OFFSTACK is not set, sd_sysctl_cpus is left uninitialized (all zeroes) and the kernel may fail to initialize sched_domain sysctl entries for all possible CPUs. This is visible to the user if the kernel is booted with maxcpus=n, or if ACPI tables have been modified to leave CPUs offline, and then checking for missing /proc/sys/kernel/sched_domain/cpu* entries. Fix this by separating the allocation and initialization, and adding a flag to initialize the possible CPU entries while system booting only. Tested-by: Syuuichirou Ishii Tested-by: Tarumizu, Kohei Signed-off-by: Hidetoshi Seto Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Masayoshi Mizuma Acked-by: Joe Lawrence Cc: Linus Torvalds Cc: Masayoshi Mizuma Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190129151245.5073-1-msys.mizuma@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

genirq: Avoid summation loops for /proc/stat

2019-04-05T20:31:35Z

[ Upstream commit 1136b0728969901a091f0471968b2b76ed14d9ad ] Waiman reported that on large systems with a large amount of interrupts the readout of /proc/stat takes a long time to sum up the interrupt statistics. In principle this is not a problem. but for unknown reasons some enterprise quality software reads /proc/stat with a high frequency. The reason for this is that interrupt statistics are accounted per cpu. So the /proc/stat logic has to sum up the interrupt stats for each interrupt. This can be largely avoided for interrupts which are not marked as 'PER_CPU' interrupts by simply adding a per interrupt summation counter which is incremented along with the per interrupt per cpu counter. The PER_CPU interrupts need to avoid that and use only per cpu accounting because they share the interrupt number and the interrupt descriptor and concurrent updates would conflict or require unwanted synchronization. Reported-by: Waiman Long Signed-off-by: Thomas Gleixner Reviewed-by: Waiman Long Reviewed-by: Marc Zyngier Reviewed-by: Davidlohr Bueso Cc: Matthew Wilcox Cc: Andrew Morton Cc: Alexey Dobriyan Cc: Kees Cook Cc: linux-fsdevel@vger.kernel.org Cc: Davidlohr Bueso Cc: Miklos Szeredi Cc: Daniel Colascione Cc: Dave Chinner Cc: Randy Dunlap Link: https://lkml.kernel.org/r/20190208135020.925487496@linutronix.de 8<------------- v2: Undo the unintentional layout change of struct irq_desc. include/linux/irqdesc.h | 1 + kernel/irq/chip.c | 12 ++++++++++-- kernel/irq/internals.h | 8 +++++++- kernel/irq/irqdesc.c | 7 ++++++- 4 files changed, 24 insertions(+), 4 deletions(-) Signed-off-by: Sasha Levin

sched/topology: Fix percpu data types in struct sd_data & struct s_data

2019-04-05T20:31:34Z

[ Upstream commit 99687cdbb3f6c8e32bcc7f37496e811f30460e48 ] The percpu members of struct sd_data and s_data are declared as: struct ... ** __percpu member; So their type is: __percpu pointer to pointer to struct ... But looking at how they're used, their type should be: pointer to __percpu pointer to struct ... and they should thus be declared as: struct ... * __percpu *member; So fix the placement of '__percpu' in the definition of these structures. This addresses a bunch of Sparse's warnings like: warning: incorrect type in initializer (different address spaces) expected void const [noderef] *__vpp_verify got struct sched_domain ** Signed-off-by: Luc Van Oostenryck Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190118144936.79158-1-luc.vanoostenryck@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

sysctl: handle overflow for file-max

2019-04-05T20:31:26Z

[ Upstream commit 32a5ad9c22852e6bd9e74bdec5934ef9d1480bc5 ] Currently, when writing echo 18446744073709551616 > /proc/sys/fs/file-max /proc/sys/fs/file-max will overflow and be set to 0. That quickly crashes the system. This commit sets the max and min value for file-max. The max value is set to long int. Any higher value cannot currently be used as the percpu counters are long ints and not unsigned integers. Note that the file-max value is ultimately parsed via __do_proc_doulongvec_minmax(). This function does not report error when min or max are exceeded. Which means if a value largen that long int is written userspace will not receive an error instead the old value will be kept. There is an argument to be made that this should be changed and __do_proc_doulongvec_minmax() should return an error when a dedicated min or max value are exceeded. However this has the potential to break userspace so let's defer this to an RFC patch. Link: http://lkml.kernel.org/r/20190107222700.15954-3-christian@brauner.io Signed-off-by: Christian Brauner Acked-by: Kees Cook Cc: Alexey Dobriyan Cc: Al Viro Cc: Dominik Brodowski Cc: "Eric W. Biederman" Cc: Joe Lawrence Cc: Luis Chamberlain Cc: Waiman Long [christian@brauner.io: v4] Link: http://lkml.kernel.org/r/20190210203943.8227-3-christian@brauner.io Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin