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2019-08-25Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "Two small fixes for kprobes and perf: - Prevent a deadlock in kprobe_optimizer() causes by reverse lock ordering - Fix a comment typo" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes: Fix potential deadlock in kprobe_optimizer() perf/x86: Fix typo in comment
2019-08-25Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fix from Thomas Gleixner: "A single fix for a imbalanced kobject operation in the irq decriptor code which was unearthed by the new warnings in the kobject code" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Properly pair kobject_del() with kobject_add()
2019-08-25Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Mergr misc fixes from Andrew Morton: "11 fixes" Mostly VM fixes, one psi polling fix, and one parisc build fix. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm/kasan: fix false positive invalid-free reports with CONFIG_KASAN_SW_TAGS=y mm/zsmalloc.c: fix race condition in zs_destroy_pool mm/zsmalloc.c: migration can leave pages in ZS_EMPTY indefinitely mm, page_owner: handle THP splits correctly userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx psi: get poll_work to run when calling poll syscall next time mm: memcontrol: flush percpu vmevents before releasing memcg mm: memcontrol: flush percpu vmstats before releasing memcg parisc: fix compilation errrors mm, page_alloc: move_freepages should not examine struct page of reserved memory mm/z3fold.c: fix race between migration and destruction
2019-08-24Merge tag 'dma-mapping-5.3-5' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull dma-mapping fixes from Christoph Hellwig: "Two fixes for regressions in this merge window: - select the Kconfig symbols for the noncoherent dma arch helpers on arm if swiotlb is selected, not just for LPAE to not break then Xen build, that uses swiotlb indirectly through swiotlb-xen - fix the page allocator fallback in dma_alloc_contiguous if the CMA allocation fails" * tag 'dma-mapping-5.3-5' of git://git.infradead.org/users/hch/dma-mapping: dma-direct: fix zone selection after an unaddressable CMA allocation arm: select the dma-noncoherent symbols for all swiotlb builds
2019-08-24psi: get poll_work to run when calling poll syscall next timeJason Xing
Only when calling the poll syscall the first time can user receive POLLPRI correctly. After that, user always fails to acquire the event signal. Reproduce case: 1. Get the monitor code in Documentation/accounting/psi.txt 2. Run it, and wait for the event triggered. 3. Kill and restart the process. The question is why we can end up with poll_scheduled = 1 but the work not running (which would reset it to 0). And the answer is because the scheduling side sees group->poll_kworker under RCU protection and then schedules it, but here we cancel the work and destroy the worker. The cancel needs to pair with resetting the poll_scheduled flag. Link: http://lkml.kernel.org/r/1566357985-97781-1-git-send-email-joseph.qi@linux.alibaba.com Signed-off-by: Jason Xing <kerneljasonxing@linux.alibaba.com> Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Caspar Zhang <caspar@linux.alibaba.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-23Merge tag 'modules-for-v5.3-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull modules fixes from Jessica Yu: "Fix BUG_ON() being triggered in frob_text() due to non-page-aligned module sections" * tag 'modules-for-v5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: modules: page-align module section allocations only for arches supporting strict module rwx modules: always page-align module section allocations
2019-08-21modules: page-align module section allocations only for arches supporting ↵He Zhe
strict module rwx We should keep the case of "#define debug_align(X) (X)" for all arches without CONFIG_HAS_STRICT_MODULE_RWX ability, which would save people, who are sensitive to system size, a lot of memory when using modules, especially for embedded systems. This is also the intention of the original #ifdef... statement and still valid for now. Note that this still keeps the effect of the fix of the following commit, 38f054d549a8 ("modules: always page-align module section allocations"), since when CONFIG_ARCH_HAS_STRICT_MODULE_RWX is enabled, module pages are aligned. Signed-off-by: He Zhe <zhe.he@windriver.com> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2019-08-21dma-direct: fix zone selection after an unaddressable CMA allocationChristoph Hellwig
The new dma_alloc_contiguous hides if we allocate CMA or regular pages, and thus fails to retry a ZONE_NORMAL allocation if the CMA allocation succeeds but isn't addressable. That means we either fail outright or dip into a small zone that might not succeed either. Thanks to Hillf Danton for debugging this issue. Fixes: b1d2dc009dec ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
2019-08-19Merge branch 'siginfo-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull kernel thread signal handling fix from Eric Biederman: "I overlooked the fact that kernel threads are created with all signals set to SIG_IGN, and accidentally caused a regression in cifs and drbd when replacing force_sig with send_sig. This is my fix for that regression. I add a new function allow_kernel_signal which allows kernel threads to receive signals sent from the kernel, but continues to ignore all signals sent from userspace. This ensures the user space interface for cifs and drbd remain the same. These kernel threads depend on blocking networking calls which block until something is received or a signal is pending. Making receiving of signals somewhat necessary for these kernel threads. Perhaps someday we can cleanup those interfaces and remove allow_kernel_signal. If not allow_kernel_signal is pretty trivial and clearly documents what is going on so I don't think we will mind carrying it" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: signal: Allow cifs and drbd to receive their terminating signals
2019-08-19genirq: Properly pair kobject_del() with kobject_add()Michael Kelley
If alloc_descs() fails before irq_sysfs_init() has run, free_desc() in the cleanup path will call kobject_del() even though the kobject has not been added with kobject_add(). Fix this by making the call to kobject_del() conditional on whether irq_sysfs_init() has run. This problem surfaced because commit aa30f47cf666 ("kobject: Add support for default attribute groups to kobj_type") makes kobject_del() stricter about pairing with kobject_add(). If the pairing is incorrrect, a WARNING and backtrace occur in sysfs_remove_group() because there is no parent. [ tglx: Add a comment to the code and make it work with CONFIG_SYSFS=n ] Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs") Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1564703564-4116-1-git-send-email-mikelley@microsoft.com
2019-08-19signal: Allow cifs and drbd to receive their terminating signalsEric W. Biederman
My recent to change to only use force_sig for a synchronous events wound up breaking signal reception cifs and drbd. I had overlooked the fact that by default kthreads start out with all signals set to SIG_IGN. So a change I thought was safe turned out to have made it impossible for those kernel thread to catch their signals. Reverting the work on force_sig is a bad idea because what the code was doing was very much a misuse of force_sig. As the way force_sig ultimately allowed the signal to happen was to change the signal handler to SIG_DFL. Which after the first signal will allow userspace to send signals to these kernel threads. At least for wake_ack_receiver in drbd that does not appear actively wrong. So correct this problem by adding allow_kernel_signal that will allow signals whose siginfo reports they were sent by the kernel through, but will not allow userspace generated signals, and update cifs and drbd to call allow_kernel_signal in an appropriate place so that their thread can receive this signal. Fixing things this way ensures that userspace won't be able to send signals and cause problems, that it is clear which signals the threads are expecting to receive, and it guarantees that nothing else in the system will be affected. This change was partly inspired by similar cifs and drbd patches that added allow_signal. Reported-by: ronnie sahlberg <ronniesahlberg@gmail.com> Reported-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Steve French <smfrench@gmail.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: David Laight <David.Laight@ACULAB.COM> Fixes: 247bc9470b1e ("cifs: fix rmmod regression in cifs.ko caused by force_sig changes") Fixes: 72abe3bcf091 ("signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig") Fixes: fee109901f39 ("signal/drbd: Use send_sig not force_sig") Fixes: 3cf5d076fb4d ("signal: Remove task parameter from force_sig") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2019-08-19kprobes: Fix potential deadlock in kprobe_optimizer()Andrea Righi
lockdep reports the following deadlock scenario: WARNING: possible circular locking dependency detected kworker/1:1/48 is trying to acquire lock: 000000008d7a62b2 (text_mutex){+.+.}, at: kprobe_optimizer+0x163/0x290 but task is already holding lock: 00000000850b5e2d (module_mutex){+.+.}, at: kprobe_optimizer+0x31/0x290 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (module_mutex){+.+.}: __mutex_lock+0xac/0x9f0 mutex_lock_nested+0x1b/0x20 set_all_modules_text_rw+0x22/0x90 ftrace_arch_code_modify_prepare+0x1c/0x20 ftrace_run_update_code+0xe/0x30 ftrace_startup_enable+0x2e/0x50 ftrace_startup+0xa7/0x100 register_ftrace_function+0x27/0x70 arm_kprobe+0xb3/0x130 enable_kprobe+0x83/0xa0 enable_trace_kprobe.part.0+0x2e/0x80 kprobe_register+0x6f/0xc0 perf_trace_event_init+0x16b/0x270 perf_kprobe_init+0xa7/0xe0 perf_kprobe_event_init+0x3e/0x70 perf_try_init_event+0x4a/0x140 perf_event_alloc+0x93a/0xde0 __do_sys_perf_event_open+0x19f/0xf30 __x64_sys_perf_event_open+0x20/0x30 do_syscall_64+0x65/0x1d0 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (text_mutex){+.+.}: __lock_acquire+0xfcb/0x1b60 lock_acquire+0xca/0x1d0 __mutex_lock+0xac/0x9f0 mutex_lock_nested+0x1b/0x20 kprobe_optimizer+0x163/0x290 process_one_work+0x22b/0x560 worker_thread+0x50/0x3c0 kthread+0x112/0x150 ret_from_fork+0x3a/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(module_mutex); lock(text_mutex); lock(module_mutex); lock(text_mutex); *** DEADLOCK *** As a reproducer I've been using bcc's funccount.py (https://github.com/iovisor/bcc/blob/master/tools/funccount.py), for example: # ./funccount.py '*interrupt*' That immediately triggers the lockdep splat. Fix by acquiring text_mutex before module_mutex in kprobe_optimizer(). Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: d5b844a2cf50 ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()") Link: http://lkml.kernel.org/r/20190812184302.GA7010@xps-13 Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-08-18Merge tag 'spdx-5.3-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX fixes from Greg KH: "Here are four small SPDX fixes for 5.3-rc5. A few style fixes for some SPDX comments, added an SPDX tag for one file, and fix up some GPL boilerplate for another file. All of these have been in linux-next for a few weeks with no reported issues (they are comment changes only, so that's to be expected...)" * tag 'spdx-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: i2c: stm32: Use the correct style for SPDX License Identifier intel_th: Use the correct style for SPDX License Identifier coccinelle: api/atomic_as_refcounter: add SPDX License Identifier kernel/configs: Replace GPL boilerplate code with SPDX identifier
2019-08-16Merge tag 'pm-5.3-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "These add a check to avoid recent suspend-to-idle power regression on systems with NVMe drives where the PCIe ASPM policy is "performance" (or when the kernel is built without ASPM support), fix an issue related to frequency limits in the schedutil cpufreq governor and fix a mistake related to the PM QoS usage in the cpufreq core introduced recently. Specifics: - Disable NVMe power optimization related to suspend-to-idle added recently on systems where PCIe ASPM is not able to put PCIe links into low-power states to prevent excess power from being drawn by the system while suspended (Rafael Wysocki). - Make the schedutil governor handle frequency limits changes properly in all cases (Viresh Kumar). - Prevent the cpufreq core from treating positive values returned by dev_pm_qos_update_request() as errors (Viresh Kumar)" * tag 'pm-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: nvme-pci: Allow PCI bus-level PM to be used if ASPM is disabled PCI/ASPM: Add pcie_aspm_enabled() cpufreq: schedutil: Don't skip freq update when limits change cpufreq: dev_pm_qos_update_request() can return 1 on success
2019-08-16Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: cpufreq: schedutil: Don't skip freq update when limits change cpufreq: dev_pm_qos_update_request() can return 1 on success
2019-08-14Merge tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull dma-mapping fixes from Christoph Hellwig: - fix the handling of the bus_dma_mask in dma_get_required_mask, which caused a regression in this merge window (Lucas Stach) - fix a regression in the handling of DMA_ATTR_NO_KERNEL_MAPPING (me) - fix dma_mmap_coherent to not cause page attribute mismatches on coherent architectures like x86 (me) * tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: fix page attributes for dma_mmap_* dma-direct: don't truncate dma_required_mask to bus addressing capabilities dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING
2019-08-10Merge 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: "Three fixlets for the scheduler: - Avoid double bandwidth accounting in the push & pull code - Use a sane FIFO priority for the Pressure Stall Information (PSI) thread. - Avoid permission checks when setting the scheduler params for the PSI thread" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/psi: Do not require setsched permission from the trigger creator sched/psi: Reduce psimon FIFO priority sched/deadline: Fix double accounting of rq/running bw in push & pull
2019-08-10dma-mapping: fix page attributes for dma_mmap_*Christoph Hellwig
All the way back to introducing dma_common_mmap we've defaulted to mark the pages as uncached. But this is wrong for DMA coherent devices. Later on DMA_ATTR_WRITE_COMBINE also got incorrect treatment as that flag is only treated special on the alloc side for non-coherent devices. Introduce a new dma_pgprot helper that deals with the check for coherent devices so that only the remapping cases ever reach arch_dma_mmap_pgprot and we thus ensure no aliasing of page attributes happens, which makes the powerpc version of arch_dma_mmap_pgprot obsolete and simplifies the remaining ones. Note that this means arch_dma_mmap_pgprot is a bit misnamed now, but we'll phase it out soon. Fixes: 64ccc9c033c6 ("common: dma-mapping: add support for generic dma_mmap_* calls") Reported-by: Shawn Anastasio <shawn@anastas.io> Reported-by: Gavin Li <git@thegavinli.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64
2019-08-10dma-direct: don't truncate dma_required_mask to bus addressing capabilitiesLucas Stach
The dma required_mask needs to reflect the actual addressing capabilities needed to handle the whole system RAM. When truncated down to the bus addressing capabilities dma_addressing_limited() will incorrectly signal no limitations for devices which are restricted by the bus_dma_mask. Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask handling) Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-08-10dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPINGChristoph Hellwig
The new DMA_ATTR_NO_KERNEL_MAPPING needs to actually assign a dma_addr to work. Also skip it if the architecture needs forced decryption handling, as that needs a kernel virtual address. Fixes: d98849aff879 (dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code) Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
2019-08-10cpufreq: schedutil: Don't skip freq update when limits changeViresh Kumar
To avoid reducing the frequency of a CPU prematurely, we skip reducing the frequency if the CPU had been busy recently. This should not be done when the limits of the policy are changed, for example due to thermal throttling. We should always get the frequency within the new limits as soon as possible. Trying to fix this by using only one flag, i.e. need_freq_update, can lead to a race condition where the flag gets cleared without forcing us to change the frequency at least once. And so this patch introduces another flag to avoid that race condition. Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX") Cc: v4.18+ <stable@vger.kernel.org> # v4.18+ Reported-by: Doug Smythies <dsmythies@telus.net> Tested-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-08genirq/affinity: Create affinity mask for single vectorMing Lei
Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating interrupt sets"), irq_create_affinity_masks() returns NULL in case of single vector. This change has caused regression on some drivers, such as lpfc. The problem is that single vector requests can happen in some generic cases: 1) kdump kernel 2) irq vectors resource is close to exhaustion. If in that situation the affinity mask for a single vector is not created, every caller has to handle the special case. There is no reason why the mask cannot be created, so remove the check for a single vector and create the mask. Fixes: c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating interrupt sets") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190805011906.5020-1-ming.lei@redhat.com
2019-08-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds
Pull networking fixes from David Miller: "Yeah I should have sent a pull request last week, so there is a lot more here than usual: 1) Fix memory leak in ebtables compat code, from Wenwen Wang. 2) Several kTLS bug fixes from Jakub Kicinski (circular close on disconnect etc.) 3) Force slave speed check on link state recovery in bonding 802.3ad mode, from Thomas Falcon. 4) Clear RX descriptor bits before assigning buffers to them in stmmac, from Jose Abreu. 5) Several missing of_node_put() calls, mostly wrt. for_each_*() OF loops, from Nishka Dasgupta. 6) Double kfree_skb() in peak_usb can driver, from Stephane Grosjean. 7) Need to hold sock across skb->destructor invocation, from Cong Wang. 8) IP header length needs to be validated in ipip tunnel xmit, from Haishuang Yan. 9) Use after free in ip6 tunnel driver, also from Haishuang Yan. 10) Do not use MSI interrupts on r8169 chips before RTL8168d, from Heiner Kallweit. 11) Upon bridge device init failure, we need to delete the local fdb. From Nikolay Aleksandrov. 12) Handle erros from of_get_mac_address() properly in stmmac, from Martin Blumenstingl. 13) Handle concurrent rename vs. dump in netfilter ipset, from Jozsef Kadlecsik. 14) Setting NETIF_F_LLTX on mac80211 causes complete breakage with some devices, so revert. From Johannes Berg. 15) Fix deadlock in rxrpc, from David Howells. 16) Fix Kconfig deps of enetc driver, we must have PHYLIB. From Yue Haibing. 17) Fix mvpp2 crash on module removal, from Matteo Croce. 18) Fix race in genphy_update_link, from Heiner Kallweit. 19) bpf_xdp_adjust_head() stopped working with generic XDP when we fixes generic XDP to support stacked devices properly, fix from Jesper Dangaard Brouer. 20) Unbalanced RCU locking in rt6_update_exception_stamp_rt(), from David Ahern. 21) Several memory leaks in new sja1105 driver, from Vladimir Oltean" * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (214 commits) net: dsa: sja1105: Fix memory leak on meta state machine error path net: dsa: sja1105: Fix memory leak on meta state machine normal path net: dsa: sja1105: Really fix panic on unregistering PTP clock net: dsa: sja1105: Use the LOCKEDS bit for SJA1105 E/T as well net: dsa: sja1105: Fix broken learning with vlan_filtering disabled net: dsa: qca8k: Add of_node_put() in qca8k_setup_mdio_bus() net: sched: sample: allow accessing psample_group with rtnl net: sched: police: allow accessing police->params with rtnl net: hisilicon: Fix dma_map_single failed on arm64 net: hisilicon: fix hip04-xmit never return TX_BUSY net: hisilicon: make hip04_tx_reclaim non-reentrant tc-testing: updated vlan action tests with batch create/delete net sched: update vlan action for batched events operations net: stmmac: tc: Do not return a fragment entry net: stmmac: Fix issues when number of Queues >= 4 net: stmmac: xgmac: Fix XGMAC selftests be2net: disable bh with spin_lock in be_process_mcc net: cxgb3_main: Fix a resource leak in a error path in 'init_one()' net: ethernet: sun4i-emac: Support phy-handle property for finding PHYs net: bridge: move default pvid init/deinit to NETDEV_REGISTER/UNREGISTER ...
2019-08-06sched/psi: Do not require setsched permission from the trigger creatorSuren Baghdasaryan
When a process creates a new trigger by writing into /proc/pressure/* files, permissions to write such a file should be used to determine whether the process is allowed to do so or not. Current implementation would also require such a process to have setsched capability. Setting of psi trigger thread's scheduling policy is an implementation detail and should not be exposed to the user level. Remove the permission check by using _nocheck version of the function. Suggested-by: Nick Kralevich <nnk@google.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: lizefan@huawei.com Cc: mingo@redhat.com Cc: akpm@linux-foundation.org Cc: kernel-team@android.com Cc: dennisszhou@gmail.com Cc: dennis@kernel.org Cc: hannes@cmpxchg.org Cc: axboe@kernel.dk Link: https://lkml.kernel.org/r/20190730013310.162367-1-surenb@google.com
2019-08-06sched/psi: Reduce psimon FIFO priorityPeter Zijlstra
PSI defaults to a FIFO-99 thread, reduce this to FIFO-1. FIFO-99 is the very highest priority available to SCHED_FIFO and it not a suitable default; it would indicate the psi work is the most important work on the machine. Since Real-Time tasks will have pre-allocated memory and locked it in place, Real-Time tasks do not care about PSI. All it needs is to be above OTHER. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2019-08-06sched/deadline: Fix double accounting of rq/running bw in push & pullDietmar Eggemann
{push,pull}_dl_task() always calls {de,}activate_task() with .flags=0 which sets p->on_rq=TASK_ON_RQ_MIGRATING. {push,pull}_dl_task()->{de,}activate_task()->{de,en}queue_task()-> {de,en}queue_task_dl() calls {sub,add}_{running,rq}_bw() since p->on_rq==TASK_ON_RQ_MIGRATING. So {sub,add}_{running,rq}_bw() in {push,pull}_dl_task() is double-accounting for that task. Fix it by removing rq/running bw accounting in [push/pull]_dl_task(). Fixes: 7dd778841164 ("sched/core: Unify p->on_rq updates") Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luca Abeni <luca.abeni@santannapisa.it> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Qais Yousef <qais.yousef@arm.com> Link: https://lkml.kernel.org/r/20190802145945.18702-2-dietmar.eggemann@arm.com
2019-08-03memremap: move from kernel/ to mm/Christoph Hellwig
memremap.c implements MM functionality for ZONE_DEVICE, so it really should be in the mm/ directory, not the kernel/ one. Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03kernel/signal.c: fix a kernel-doc markupMauro Carvalho Chehab
The kernel-doc parser doesn't handle expressions with %foo*. Instead, when an asterisk should be part of a constant, it uses an alternative notation: `foo*`. Link: http://lkml.kernel.org/r/7f18c2e0b5e39e6b7eb55ddeb043b8b260b49f2d.1563361575.git.mchehab+samsung@kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-02Merge tag 'arm-swiotlb-5.3' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull arm swiotlb support from Christoph Hellwig: "This fixes a cascade of regressions that originally started with the addition of the ia64 port, but only got fatal once we removed most uses of block layer bounce buffering in Linux 4.18. The reason is that while the original i386/PAE code that was the first architecture that supported > 4GB of memory without an iommu decided to leave bounce buffering to the subsystems, which in those days just mean block and networking as no one else consumed arbitrary userspace memory. Later with ia64, x86_64 and other ports we assumed that either an iommu or something that fakes it up ("software IOTLB" in beautiful Intel speak) is present and that subsystems can rely on that for dealing with addressing limitations in devices. Except that the ARM LPAE scheme that added larger physical address to 32-bit ARM did not follow that scheme and thus only worked by chance and only for block and networking I/O directly to highmem. Long story, short fix - add swiotlb support to arm when build for LPAE platforms, which actuallys turns out to be pretty trivial with the modern dma-direct / swiotlb code to fix the Linux 4.18-ish regression" * tag 'arm-swiotlb-5.3' of git://git.infradead.org/users/hch/dma-mapping: arm: use swiotlb for bounce buffering on LPAE configs dma-mapping: check pfn validity in dma_common_{mmap,get_sgtable}
2019-08-02Merge tag 'dma-mapping-5.3-3' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull dma-mapping regression fixes from Christoph Hellwig: "Two related regression fixes for changes from this merge window to fix alignment issues introduced in the CMA allocation rework (Nicolin Chen)" * tag 'dma-mapping-5.3-3' of git://git.infradead.org/users/hch/dma-mapping: dma-contiguous: page-align the size in dma_free_contiguous() dma-contiguous: do not overwrite align in dma_alloc_contiguous()
2019-07-31Merge tag 'trace-v5.3-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Two minor fixes: - Fix trace event header include guards, as several did not match the #define to the #ifdef - Remove a redundant test to ftrace_graph_notrace_addr() that was accidentally added" * tag 'trace-v5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: fgraph: Remove redundant ftrace_graph_notrace_addr() test tracing: Fix header include guards in trace event headers
2019-07-30fgraph: Remove redundant ftrace_graph_notrace_addr() testChangbin Du
We already have tested it before. The second one should be removed. With this change, the performance should have little improvement. Link: http://lkml.kernel.org/r/20190730140850.7927-1-changbin.du@gmail.com Cc: stable@vger.kernel.org Fixes: 9cd2992f2d6c ("fgraph: Have set_graph_notrace only affect function_graph tracer") Signed-off-by: Changbin Du <changbin.du@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-07-30exit: make setting exit_state consistentChristian Brauner
Since commit b191d6491be6 ("pidfd: fix a poll race when setting exit_state") we unconditionally set exit_state to EXIT_ZOMBIE before calling into do_notify_parent(). This was done to eliminate a race when querying exit_state in do_notify_pidfd(). Back then we decided to do the absolute minimal thing to fix this and not touch the rest of the exit_notify() function where exit_state is set. Since this fix has not caused any issues change the setting of exit_state to EXIT_DEAD in the autoreap case to account for the fact hat exit_state is set to EXIT_ZOMBIE unconditionally. This fix was planned but also explicitly requested in [1] and makes the whole code more consistent. /* References */ [1]: https://lore.kernel.org/lkml/CAHk-=wigcxGFR2szue4wavJtH5cYTTeNES=toUBVGsmX0rzX+g@mail.gmail.com Signed-off-by: Christian Brauner <christian@brauner.io> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-30kernel/configs: Replace GPL boilerplate code with SPDX identifierThomas Huth
The FSF does not reside in "675 Mass Ave, Cambridge" anymore... let's replace the old GPL boilerplate code with a proper SPDX identifier instead. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30modules: always page-align module section allocationsJessica Yu
Some arches (e.g., arm64, x86) have moved towards non-executable module_alloc() allocations for security hardening reasons. That means that the module loader will need to set the text section of a module to executable, regardless of whether or not CONFIG_STRICT_MODULE_RWX is set. When CONFIG_STRICT_MODULE_RWX=y, module section allocations are always page-aligned to handle memory rwx permissions. On some arches with CONFIG_STRICT_MODULE_RWX=n however, when setting the module text to executable, the BUG_ON() in frob_text() gets triggered since module section allocations are not page-aligned when CONFIG_STRICT_MODULE_RWX=n. Since the set_memory_* API works with pages, and since we need to call set_memory_x() regardless of whether CONFIG_STRICT_MODULE_RWX is set, we might as well page-align all module section allocations for ease of managing rwx permissions of module sections (text, rodata, etc). Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n") Reported-by: Martin Kaiser <lists@kaiser.cx> Reported-by: Bartosz Golaszewski <brgl@bgdev.pl> Tested-by: David Lechner <david@lechnology.com> Tested-by: Martin Kaiser <martin@kaiser.cx> Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2019-07-29pidfd: Add warning if exit_state is 0 during notificationJoel Fernandes (Google)
Previously a condition got missed where the pidfd waiters are awakened before the exit_state gets set. This can result in a missed notification [1] and the polling thread waiting forever. It is fixed now, however it would be nice to avoid this kind of issue going unnoticed in the future. So just add a warning to catch it in the future. /* References */ [1]: https://lore.kernel.org/lkml/20190717172100.261204-1-joel@joelfernandes.org/ Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Link: https://lore.kernel.org/r/20190724164816.201099-1-joel@joelfernandes.org Signed-off-by: Christian Brauner <christian@brauner.io>
2019-07-29dma-contiguous: page-align the size in dma_free_contiguous()Nicolin Chen
According to the original dma_direct_alloc_pages() code: { unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; if (!dma_release_from_contiguous(dev, page, count)) __free_pages(page, get_order(size)); } The count parameter for dma_release_from_contiguous() was page aligned before the right-shifting operation, while the new API dma_free_contiguous() forgets to have PAGE_ALIGN() at the size. So this patch simply adds it to prevent any corner case. Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-07-29dma-contiguous: do not overwrite align in dma_alloc_contiguous()Nicolin Chen
The dma_alloc_contiguous() limits align at CONFIG_CMA_ALIGNMENT for cma_alloc() however it does not restore it for the fallback routine. This will result in a size mismatch between the allocation and free when running into the fallback routines after cma_alloc() fails, if the align is larger than CONFIG_CMA_ALIGNMENT. This patch adds a cma_align to take care of cma_alloc() and prevent the align from being overwritten. Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Reported-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-07-27Merge 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: "Two fixes for the fair scheduling class: - Prevent freeing memory which is accessible by concurrent readers - Make the RCU annotations for numa groups consistent" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Use RCU accessors consistently for ->numa_group sched/fair: Don't free p->numa_faults with concurrent readers
2019-07-27Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "A pile of perf related fixes: Kernel: - Fix SLOTS PEBS event constraints for Icelake CPUs - Add the missing mask bit to allow counting hardware generated prefetches on L3 for Icelake CPUs - Make the test for hypervisor platforms more accurate (as far as possible) - Handle PMUs correctly which override event->cpu - Yet another missing fallthrough annotation Tools: perf.data: - Fix loading of compressed data split across adjacent records - Fix buffer size setting for processing CPU topology perf.data header. perf stat: - Fix segfault for event group in repeat mode - Always separate "stalled cycles per insn" line, it was being appended to the "instructions" line. perf script: - Fix --max-blocks man page description. - Improve man page description of metrics. - Fix off by one in brstackinsn IPC computation. perf probe: - Avoid calling freeing routine multiple times for same pointer. perf build: - Do not use -Wshadow on gcc < 4.8, avoiding too strict warnings treated as errors, breaking the build" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel: Mark expected switch fall-throughs perf/core: Fix creating kernel counters for PMUs that override event->cpu perf/x86: Apply more accurate check on hypervisor platform perf/x86/intel: Fix invalid Bit 13 for Icelake MSR_OFFCORE_RSP_x register perf/x86/intel: Fix SLOTS PEBS event constraint perf build: Do not use -Wshadow on gcc < 4.8 perf probe: Avoid calling freeing routine multiple times for same pointer perf probe: Set pev->nargs to zero after freeing pev->args entries perf session: Fix loading of compressed data split across adjacent records perf stat: Always separate stalled cycles per insn perf stat: Fix segfault for event group in repeat mode perf tools: Fix proper buffer size for feature processing perf script: Fix off by one in brstackinsn IPC computation perf script: Improve man page description of metrics perf script: Fix --max-blocks man page description
2019-07-27Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Thomas Gleixner: "A set of locking fixes: - Address the fallout of the rwsem rework. Missing ACQUIREs and a sanity check to prevent a use-after-free - Add missing checks for unitialized mutexes when mutex debugging is enabled. - Remove the bogus code in the generic SMP variant of arch_futex_atomic_op_inuser() - Fixup the #ifdeffery in lockdep to prevent compile warnings" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/mutex: Test for initialized mutex locking/lockdep: Clean up #ifdef checks locking/lockdep: Hide unused 'class' variable locking/rwsem: Add ACQUIRE comments tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop locking/rwsem: Add missing ACQUIRE to read_slowpath exit when queue is empty locking/rwsem: Don't call owner_on_cpu() on read-owner futex: Cleanup generic SMP variant of arch_futex_atomic_op_inuser()
2019-07-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf 2019-07-25 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) fix segfault in libbpf, from Andrii. 2) fix gso_segs access, from Eric. 3) tls/sockmap fixes, from Jakub and John. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-25Merge branch 'access-creds'Linus Torvalds
The access() (and faccessat()) credentials change can cause an unnecessary load on the RCU machinery because every access() call ends up freeing the temporary access credential using RCU. This isn't really noticeable on small machines, but if you have hundreds of cores you can cause huge slowdowns due to RCU storms. It's easy to avoid: the temporary access crededntials aren't actually normally accessed using RCU at all, so we can avoid the whole issue by just marking them as such. * access-creds: access: avoid the RCU grace period for the temporary subjective credentials
2019-07-25perf/core: Fix creating kernel counters for PMUs that override event->cpuLeonard Crestez
Some hardware PMU drivers will override perf_event.cpu inside their event_init callback. This causes a lockdep splat when initialized through the kernel API: WARNING: CPU: 0 PID: 250 at kernel/events/core.c:2917 ctx_sched_out+0x78/0x208 pc : ctx_sched_out+0x78/0x208 Call trace: ctx_sched_out+0x78/0x208 __perf_install_in_context+0x160/0x248 remote_function+0x58/0x68 generic_exec_single+0x100/0x180 smp_call_function_single+0x174/0x1b8 perf_install_in_context+0x178/0x188 perf_event_create_kernel_counter+0x118/0x160 Fix this by calling perf_install_in_context with event->cpu, just like perf_event_open Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Frank Li <Frank.li@nxp.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/c4ebe0503623066896d7046def4d6b1e06e0eb2e.1563972056.git.leonard.crestez@nxp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25locking/mutex: Test for initialized mutexSebastian Andrzej Siewior
An uninitialized/ zeroed mutex will go unnoticed because there is no check for it. There is a magic check in the unlock's slowpath path which might go unnoticed if the unlock happens in the fastpath. Add a ->magic check early in the mutex_lock() and mutex_trylock() path. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190703092125.lsdf4gpsh2plhavb@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25locking/lockdep: Clean up #ifdef checksArnd Bergmann
As Will Deacon points out, CONFIG_PROVE_LOCKING implies TRACE_IRQFLAGS, so the conditions I added in the previous patch, and some others in the same file can be simplified by only checking for the former. No functional change. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Yuyang Du <duyuyang@gmail.com> Fixes: 886532aee3cd ("locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING") Link: https://lkml.kernel.org/r/20190628102919.2345242-1-arnd@arndb.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25locking/lockdep: Hide unused 'class' variableArnd Bergmann
The usage is now hidden in an #ifdef, so we need to move the variable itself in there as well to avoid this warning: kernel/locking/lockdep_proc.c:203:21: error: unused variable 'class' [-Werror,-Wunused-variable] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Yuyang Du <duyuyang@gmail.com> Cc: frederic@kernel.org Fixes: 68d41d8c94a3 ("locking/lockdep: Fix lock used or unused stats error") Link: https://lkml.kernel.org/r/20190715092809.736834-1-arnd@arndb.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25locking/rwsem: Add ACQUIRE commentsPeter Zijlstra
Since we just reviewed read_slowpath for ACQUIRE correctness, add a few coments to retain our findings. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loopPeter Zijlstra
While reviewing another read_slowpath patch, both Will and I noticed another missing ACQUIRE, namely: X = 0; CPU0 CPU1 rwsem_down_read() for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); X = 1; rwsem_up_write(); rwsem_mark_wake() atomic_long_add(adjustment, &sem->count); smp_store_release(&waiter->task, NULL); if (!waiter.task) break; ... } r = X; Allows 'r == 0'. Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reported-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25locking/rwsem: Add missing ACQUIRE to read_slowpath exit when queue is emptyJan Stancek
LTP mtest06 has been observed to occasionally hit "still mapped when deleted" and following BUG_ON on arm64. The extra mapcount originated from pagefault handler, which handled pagefault for vma that has already been detached. vma is detached under mmap_sem write lock by detach_vmas_to_be_unmapped(), which also invalidates vmacache. When the pagefault handler (under mmap_sem read lock) calls find_vma(), vmacache_valid() wrongly reports vmacache as valid. After rwsem down_read() returns via 'queue empty' path (as of v5.2), it does so without an ACQUIRE on sem->count: down_read() __down_read() rwsem_down_read_failed() __rwsem_down_read_failed_common() raw_spin_lock_irq(&sem->wait_lock); if (list_empty(&sem->wait_list)) { if (atomic_long_read(&sem->count) >= 0) { raw_spin_unlock_irq(&sem->wait_lock); return sem; The problem can be reproduced by running LTP mtest06 in a loop and building the kernel (-j $NCPUS) in parallel. It does reproduces since v4.20 on arm64 HPE Apollo 70 (224 CPUs, 256GB RAM, 2 nodes). It triggers reliably in about an hour. The patched kernel ran fine for 10+ hours. Signed-off-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Will Deacon <will@kernel.org> Acked-by: Waiman Long <longman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dbueso@suse.de Fixes: 4b486b535c33 ("locking/rwsem: Exit read lock slowpath if queue empty & no writer") Link: https://lkml.kernel.org/r/50b8914e20d1d62bb2dee42d342836c2c16ebee7.1563438048.git.jstancek@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>