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* genirq/debugfs: Fix build for !CONFIG_IRQ_DOMAINSebastian Ott2017-07-041-1/+3
| | | | | | | | | | | | | | | Fix this build error: kernel/irq/internals.h:440:20: error: inlining failed in call to always_inline 'irq_domain_debugfs_init': function body not available kernel/irq/debugfs.c:202:2: note: called from here irq_domain_debugfs_init(root_dir); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.LFD.2.20.1707041124000.1712@schleppi
* Merge branch 'ras-core-for-linus' of ↵Linus Torvalds2017-07-0318-730/+759
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RAS updates from Thomas Gleixner: "The RAS updates for the 4.13 merge window: - Cleanup of the MCE injection facility (Borsilav Petkov) - Rework of the AMD/SMCA handling (Yazen Ghannam) - Enhancements for ACPI/APEI to handle new notitication types (Shiju Jose) - atomic_t to refcount_t conversion (Elena Reshetova) - A few fixes and enhancements all over the place" * 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: RAS/CEC: Check the correct variable in the debugfs error handling x86/mce: Always save severity in machine_check_poll() x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise x86/mce: Update bootlog description to reflect behavior on AMD x86/mce: Don't disable MCA banks when offlining a CPU on AMD x86/mce/mce-inject: Preset the MCE injection struct x86/mce: Clean up include files x86/mce: Get rid of register_mce_write_callback() x86/mce: Merge mce_amd_inj into mce-inject x86/mce/AMD: Use saved threshold block info in interrupt handler x86/mce/AMD: Use msr_stat when clearing MCA_STATUS x86/mce/AMD: Carve out SMCA bank configuration x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers x86/mce: Convert threshold_bank.cpus from atomic_t to refcount_t RAS: Make local function parse_ras_param() static ACPI/APEI: Handle GSIV and GPIO notification types
| * RAS/CEC: Check the correct variable in the debugfs error handlingChristophe JAILLET2017-06-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Check the correct variable when handling a potential error from debugfs_create_file(). Most likely a copy-paste botch. [ Rewrite commit message. ] Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170623062440.6726-1-christophe.jaillet@wanadoo.fr
| * x86/mce: Always save severity in machine_check_poll()Yazen Ghannam2017-06-261-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The MCE severity gives a hint as to how to handle the error. The notifier blocks can then use the severity to decide on an action. It's not necessary for machine_check_poll() to filter errors for the notifier chain, since each block will check its own set of conditions before handling an error. Also, there isn't any urgency for machine_check_poll() to make decisions based on severity like in do_machine_check(). If we can assume that a severity is set then we can use it in more notifier blocks. For example, the CEC block could check for a "KEEP" severity rather than checking bits in the status. This isn't possible now since the severity is not set except for "DEFFRRED/UCNA" errors with a valid address. Save the severity since we have it, and let the notifier blocks decide if they want to do anything. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1498074402-98633-1-git-send-email-Yazen.Ghannam@amd.com
| * x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more preciseJuergen Gross2017-06-202-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running under Xen as dom0, /dev/mcelog is being provided by Xen instead of the normal mcelog character device of the MCE core. Convert an error message being issued by the MCE core in this case to an informative message that Xen has registered the device. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel@lists.xenproject.org Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/20170614084059.19294-1-jgross@suse.com
| * x86/mce: Update bootlog description to reflect behavior on AMDYazen Ghannam2017-06-142-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The bootlog option is only disabled by default on AMD Fam10h and older systems. Update bootlog description to say this. Change the family value to hex to avoid confusion. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/20170613162835.30750-9-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce: Don't disable MCA banks when offlining a CPU on AMDYazen Ghannam2017-06-141-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | AMD systems have non-core, shared MCA banks within a die. These banks are controlled by a master CPU per die. If this CPU is offlined then all the shared banks are disabled in addition to the CPU's core banks. Also, Fam17h systems may have SMT enabled. The MCA_CTL register is shared between SMT thread siblings. If a CPU is offlined then all its sibling's MCA banks are also disabled. Extend the existing vendor check to AMD too. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> [ Fix up comment. ] Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/20170613162835.30750-8-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce/mce-inject: Preset the MCE injection structBorislav Petkov2017-06-141-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Populate the MCE injection struct before doing initial injection so that values which don't change have sane defaults. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-7-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce: Clean up include filesBorislav Petkov2017-06-141-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Not really needed. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-6-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce: Get rid of register_mce_write_callback()Borislav Petkov2017-06-144-62/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make the mcelog call a notifier which lands in the injector module and does the injection. This allows for mce-inject to be a normal kernel module now. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-5-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce: Merge mce_amd_inj into mce-injectBorislav Petkov2017-06-147-524/+532
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reuse mce_amd_inj's debugfs interface so that mce-inject can benefit from it too. The old functionality is still preserved under CONFIG_X86_MCELOG_LEGACY. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-4-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce/AMD: Use saved threshold block info in interrupt handlerYazen Ghannam2017-06-141-31/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the amd_threshold_interrupt() handler, we loop through every possible block in each bank and rediscover the block's address and if it's valid, e.g. valid, counter present and not locked. However, we already have the address saved in the threshold blocks list for each CPU and bank. The list only contains blocks that have passed all the valid checks. Besides the redundancy, there's also a smp_call_function* in get_block_address() which causes a warning when servicing the interrupt: WARNING: CPU: 0 PID: 0 at kernel/smp.c:281 smp_call_function_single+0xdd/0xf0 ... Call Trace: <IRQ> rdmsr_safe_on_cpu() get_block_address.isra.2() amd_threshold_interrupt() smp_threshold_interrupt() threshold_interrupt() because we do get called in an interrupt handler *with* interrupts disabled, which can result in a deadlock. Drop the redundant valid checks and move the overflow check, logging and block reset into a separate function. Check the first block then iterate over the rest. This procedure is needed since the first block is used as the head of the list. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/20170613162835.30750-3-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * x86/mce/AMD: Use msr_stat when clearing MCA_STATUSYazen Ghannam2017-06-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The value of MCA_STATUS is used as the MSR when clearing MCA_STATUS. This may cause the following warning: unchecked MSR access error: WRMSR to 0x11b (tried to write 0x0000000000000000) Call Trace: <IRQ> smp_threshold_interrupt() threshold_interrupt() Use msr_stat instead which has the MSR address. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Fixes: 37d43acfd79f ("x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers") Link: http://lkml.kernel.org/r/20170613162835.30750-2-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Merge tag 'v4.12-rc5' into ras/core, to pick up fixesIngo Molnar2017-06-14868-5343/+9848
| |\ | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | x86/mce/AMD: Carve out SMCA bank configurationYazen Ghannam2017-05-211-38/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Scalable MCA systems have a new MCA_CONFIG register that we use to configure each bank. We currently use this when we set up thresholding. However, this is logically separate. Group all SMCA-related initialization into a single function. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/1493147772-2721-2-git-send-email-Yazen.Ghannam@amd.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | x86/mce/AMD: Redo error logging from APIC LVT interrupt handlersYazen Ghannam2017-05-211-73/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have support for the new SMCA MCA_DE{STAT,ADDR} registers in Linux. So we've used these registers in place of MCA_{STATUS,ADDR} on SMCA systems. However, the guidance for current SMCA implementations of is to continue using MCA_{STATUS,ADDR} and to use MCA_DE{STAT,ADDR} only if a Deferred error was not found in the former registers. If we logged a Deferred error in MCA_STATUS then we should also clear MCA_DESTAT. This also means we shouldn't clear MCA_CONFIG[LogDeferredInMcaStat]. Rework __log_error() to only log an error and add helpers for the different error types being logged from the corresponding interrupt handlers. Boris: carve out common functionality into a _log_error_bank(). Cleanup comments, check MCi_STATUS bits before reading MSRs. Streamline flow. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/1493147772-2721-1-git-send-email-Yazen.Ghannam@amd.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | x86/mce: Convert threshold_bank.cpus from atomic_t to refcount_tElena Reshetova2017-05-212-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: David Windsor <dwindsor@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yazen Ghannam <Yazen.Ghannam@amd.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/1492695536-5947-1-git-send-email-elena.reshetova@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | RAS: Make local function parse_ras_param() staticWei Yongjun2017-05-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make parse_ras_param() static as it is used locally only. Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20170516161034.2973-1-weiyj.lk@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | ACPI/APEI: Handle GSIV and GPIO notification typesShiju Jose2017-05-211-14/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | System Controller Interrupts are received by ACPI's error device, which in turn notifies the GHES code. The same is true of APEI's GSIV and GPIO notification types. Add support for GSIV and GPIO sharing the SCI register/unregister/notifier code. Rename the list and notifier to show this is no longer just SCI, but anything from the Hardware Error Device. Signed-off-by: Shiju Jose <shiju.jose@huawei.com> [ Rewrite commit log. ] Signed-off-by: James Morse <james.morse@arm.com> [ Some small cleanups ontop. ] Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Tyler Baicar <tbaicar@codeaurora.org> Reviewed-by: James Morse <james.morse@arm.com> Link: http://lkml.kernel.org/r/86258A5CC0A3704780874CF6004BA8A62E695201@FRAEML521-MBX.china.huawei.com Cc: "Guohanjun (Hanjun Guo)" <guohanjun@huawei.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: "Zhengqiang (turing)" <zhengqiang10@huawei.com> Cc: "fu.wei@linaro.org" <fu.wei@linaro.org> Cc: "xuwei (O)" <xuwei5@hisilicon.com> Cc: Gabriele Paoloni <gabriele.paoloni@huawei.com> Cc: Geliang Tang <geliangtang@gmail.com> Cc: John Garry <john.garry@huawei.com> Cc: Len Brown <lenb@kernel.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Punit Agrawal <punit.agrawal@arm.com> Cc: linux-acpi@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds2017-07-0340-375/+474
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP hotplug updates from Thomas Gleixner: "This update is primarily a cleanup of the CPU hotplug locking code. The hotplug locking mechanism is an open coded RWSEM, which allows recursive locking. The main problem with that is the recursive nature as it evades the full lockdep coverage and hides potential deadlocks. The rework replaces the open coded RWSEM with a percpu RWSEM and establishes full lockdep coverage that way. The bulk of the changes fix up recursive locking issues and address the now fully reported potential deadlocks all over the place. Some of these deadlocks have been observed in the RT tree, but on mainline the probability was low enough to hide them away." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) cpu/hotplug: Constify attribute_group structures powerpc: Only obtain cpu_hotplug_lock if called by rtasd ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init cpu/hotplug: Remove unused check_for_tasks() function perf/core: Don't release cred_guard_mutex if not taken cpuhotplug: Link lock stacks for hotplug callbacks acpi/processor: Prevent cpu hotplug deadlock sched: Provide is_percpu_thread() helper cpu/hotplug: Convert hotplug locking to percpu rwsem s390: Prevent hotplug rwsem recursion arm: Prevent hotplug rwsem recursion arm64: Prevent cpu hotplug rwsem recursion kprobes: Cure hotplug lock ordering issues jump_label: Reorder hotplug lock and jump_label_lock perf/tracing/cpuhotplug: Fix locking order ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() PCI: Replace the racy recursion prevention PCI: Use cpu_hotplug_disable() instead of get_online_cpus() perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() x86/perf: Drop EXPORT of perf_check_microcode ...
| * | | cpu/hotplug: Constify attribute_group structuresArvind Yadav2017-06-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | attribute_groups are not supposed to change at runtime. All functions working with attribute_groups provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const: File size before: text data bss dec hex filename 12582 15361 20 27963 6d3b kernel/cpu.o File size After adding 'const': text data bss dec hex filename 12710 15265 20 27995 6d5b kernel/cpu.o Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: anna-maria@linutronix.de Cc: bigeasy@linutronix.de Cc: boris.ostrovsky@oracle.com Cc: rcochran@linutronix.de Link: http://lkml.kernel.org/r/f9079e94e12b36d245e7adbf67d312bc5d0250c6.1498737970.git.arvind.yadav.cs@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | powerpc: Only obtain cpu_hotplug_lock if called by rtasdThiago Jung Bauermann2017-06-233-4/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calling arch_update_cpu_topology from a CPU hotplug state machine callback hits a deadlock because the function tries to get a read lock on cpu_hotplug_lock while the state machine still holds a write lock on it. Since all callers of arch_update_cpu_topology except rtasd already hold cpu_hotplug_lock, this patch changes the function to use stop_machine_cpuslocked and creates a separate function for rtasd which still tries to obtain the lock. Michael Bringmann investigated the bug and provided a detailed analysis of the deadlock on this previous RFC for an alternate solution: Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: John Allen <jallen@linux.vnet.ibm.com> Cc: Michael Bringmann <mwb@linux.vnet.ibm.com> Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com Link: https://patchwork.ozlabs.org/patch/771293/
| * | | ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_initTony Lindgren2017-06-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recent change to use cpuhp_setup_state_cpuslocked() with commit fe2a5cd8aa03 ("ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()") missed to change the related paired cpuhp_remove_state_nocalls_cpuslocked(). Now if arch_hw_breakpoint_init() fails, we get "WARNING: possible recursive locking detected" on the exit path. Fixes: fe2a5cd8aa03 ("ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()") Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-omap@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <linux@armlinux.org.uk> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170616082238.15553-1-tony@atomide.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | cpu/hotplug: Remove unused check_for_tasks() functionArnd Bergmann2017-06-121-24/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | clang -Wunused-function found one remaining function that was apparently meant to be removed in a recent code cleanup: kernel/cpu.c:565:20: warning: unused function 'check_for_tasks' [-Wunused-function] Sebastian explained: The function became unused unintentionally, but there is already a failure check, when a task cannot be removed from the outgoing cpu in the scheduler code, so bringing it back is not really giving any extra value. Fixes: 530e9b76ae8f ("cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Link: http://lkml.kernel.org/r/20170608085544.2257132-1-arnd@arndb.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | perf/core: Don't release cred_guard_mutex if not takenAlexander Levin2017-06-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we failed to acquire task's cred_guard_mutex we shouldn't proceed to release it in the error path. Fixes: a63fbed776c ("perf/tracing/cpuhotplug: Fix locking order") Signed-off-by: Alexander Levin <alexander.levin@verizon.com> Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: mhiramat@kernel.org Cc: paulmck@linux.vnet.ibm.com Cc: bigeasy@linutronix.de Link: http://lkml.kernel.org/r/20170603033903.12056-1-alexander.levin@verizon.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | cpuhotplug: Link lock stacks for hotplug callbacksThomas Gleixner2017-05-261-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CPU hotplug callbacks are not covered by lockdep versus the cpu hotplug rwsem. CPU0 CPU1 cpuhp_setup_state(STATE, startup, teardown); cpus_read_lock(); invoke_callback_on_ap(); kick_hotplug_thread(ap); wait_for_completion(); hotplug_thread_fn() lock(m); do_stuff(); unlock(m); Lockdep does not know about this dependency and will not trigger on the following code sequence: lock(m); cpus_read_lock(); Add a lockdep map and connect the initiators lock chain with the hotplug thread lock chain, so potential deadlocks can be detected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081549.709375845@linutronix.de
| * | | acpi/processor: Prevent cpu hotplug deadlockThomas Gleixner2017-05-261-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the enhanced CPU hotplug lockdep coverage the following lockdep splat happens: ====================================================== WARNING: possible circular locking dependency detected 4.12.0-rc2+ #84 Tainted: G W ------------------------------------------------------ cpuhp/1/15 is trying to acquire lock: flush_work+0x39/0x2f0 but task is already holding lock: cpuhp_thread_fun+0x30/0x160 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (cpuhp_state){+.+.+.}: lock_acquire+0xb4/0x200 cpuhp_kick_ap_work+0x72/0x330 _cpu_down+0x8b/0x100 do_cpu_down+0x3e/0x60 cpu_down+0x10/0x20 cpu_subsys_offline+0x14/0x20 device_offline+0x88/0xb0 online_store+0x4c/0xa0 dev_attr_store+0x18/0x30 sysfs_kf_write+0x45/0x60 kernfs_fop_write+0x156/0x1e0 __vfs_write+0x37/0x160 vfs_write+0xca/0x1c0 SyS_write+0x58/0xc0 entry_SYSCALL_64_fastpath+0x23/0xc2 -> #1 (cpu_hotplug_lock.rw_sem){++++++}: lock_acquire+0xb4/0x200 cpus_read_lock+0x3d/0xb0 apply_workqueue_attrs+0x17/0x50 __alloc_workqueue_key+0x1e1/0x530 scsi_host_alloc+0x373/0x480 [scsi_mod] ata_scsi_add_hosts+0xcb/0x130 [libata] ata_host_register+0x11a/0x2c0 [libata] ata_host_activate+0xf0/0x150 [libata] ahci_host_activate+0x13e/0x170 [libahci] ahci_init_one+0xa3a/0xd3f [ahci] local_pci_probe+0x45/0xa0 work_for_cpu_fn+0x14/0x20 process_one_work+0x1f9/0x690 worker_thread+0x200/0x3d0 kthread+0x138/0x170 ret_from_fork+0x31/0x40 -> #0 ((&wfc.work)){+.+.+.}: __lock_acquire+0x11e1/0x13e0 lock_acquire+0xb4/0x200 flush_work+0x5c/0x2f0 work_on_cpu+0xa1/0xd0 acpi_processor_get_throttling+0x3d/0x50 acpi_processor_reevaluate_tstate+0x2c/0x50 acpi_soft_cpu_online+0x69/0xd0 cpuhp_invoke_callback+0xb4/0x8b0 cpuhp_up_callbacks+0x36/0xc0 cpuhp_thread_fun+0x14e/0x160 smpboot_thread_fn+0x1e8/0x300 kthread+0x138/0x170 ret_from_fork+0x31/0x40 other info that might help us debug this: Chain exists of: (&wfc.work) --> cpu_hotplug_lock.rw_sem --> cpuhp_state Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpuhp_state); lock(cpu_hotplug_lock.rw_sem); lock(cpuhp_state); lock((&wfc.work)); *** DEADLOCK *** 1 lock held by cpuhp/1/15: cpuhp_thread_fun+0x30/0x160 stack backtrace: CPU: 1 PID: 15 Comm: cpuhp/1 Tainted: G W 4.12.0-rc2+ #84 Hardware name: Supermicro SYS-4048B-TR4FT/X10QBi, BIOS 1.1a 07/29/2015 Call Trace: dump_stack+0x85/0xc4 print_circular_bug+0x209/0x217 __lock_acquire+0x11e1/0x13e0 lock_acquire+0xb4/0x200 ? lock_acquire+0xb4/0x200 ? flush_work+0x39/0x2f0 ? acpi_processor_start+0x50/0x50 flush_work+0x5c/0x2f0 ? flush_work+0x39/0x2f0 ? acpi_processor_start+0x50/0x50 ? mark_held_locks+0x6d/0x90 ? queue_work_on+0x56/0x90 ? trace_hardirqs_on_caller+0x154/0x1c0 ? trace_hardirqs_on+0xd/0x10 ? acpi_processor_start+0x50/0x50 work_on_cpu+0xa1/0xd0 ? find_worker_executing_work+0x50/0x50 ? acpi_processor_power_exit+0x70/0x70 acpi_processor_get_throttling+0x3d/0x50 acpi_processor_reevaluate_tstate+0x2c/0x50 acpi_soft_cpu_online+0x69/0xd0 cpuhp_invoke_callback+0xb4/0x8b0 ? lock_acquire+0xb4/0x200 ? padata_replace+0x120/0x120 cpuhp_up_callbacks+0x36/0xc0 cpuhp_thread_fun+0x14e/0x160 smpboot_thread_fn+0x1e8/0x300 kthread+0x138/0x170 ? sort_range+0x30/0x30 ? kthread_create_on_node+0x70/0x70 ret_from_fork+0x31/0x40 The problem is that the work is scheduled on the current CPU from the hotplug thread associated with that CPU. It's not required to invoke these functions via the workqueue because the hotplug thread runs on the target CPU already. Check whether current is a per cpu thread pinned on the target CPU and invoke the function directly to avoid the workqueue. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-acpi@vger.kernel.org Cc: Len Brown <lenb@kernel.org> Link: http://lkml.kernel.org/r/20170524081549.620489733@linutronix.de
| * | | sched: Provide is_percpu_thread() helperThomas Gleixner2017-05-261-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a helper function for checking whether current task is a per cpu thread. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081549.541649540@linutronix.de
| * | | cpu/hotplug: Convert hotplug locking to percpu rwsemThomas Gleixner2017-05-262-95/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are no more (known) nested calls to get_online_cpus() and all observed lock ordering problems have been addressed. Replace the magic nested 'rwsem' hackery with a percpu-rwsem. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081549.447014063@linutronix.de
| * | | s390: Prevent hotplug rwsem recursionThomas Gleixner2017-05-262-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The text patching functions which are invoked from jump_label and kprobes code are protected against cpu hotplug at the call sites. Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any unprotected callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/20170524081549.354513406@linutronix.de
| * | | arm: Prevent hotplug rwsem recursionThomas Gleixner2017-05-262-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The text patching functions which are invoked from jump_label and kprobes code are protected against cpu hotplug at the call sites. Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any unprotected callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <linux@armlinux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081549.275871311@linutronix.de
| * | | arm64: Prevent cpu hotplug rwsem recursionThomas Gleixner2017-05-262-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The text patching functions which are invoked from jump_label and kprobes code are protected against cpu hotplug at the call sites. Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any unprotected callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081549.197070135@linutronix.de
| * | | kprobes: Cure hotplug lock ordering issuesThomas Gleixner2017-05-261-27/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Converting the cpu hotplug locking to a percpu rwsem unearthed hidden lock ordering problems. There is a wide range of locks involved in this: kprobe_mutex, jump_label_mutex, ftrace_lock, text_mutex, event_mutex, module_mutex, func_hash->regex_lock and a gazillion of lock order permutations with nested get_online_cpus() calls. Some of those permutations are potential deadlocks even with the current nesting hotplug locking scheme, but they can't be discovered by lockdep. The conversion of the hotplug locking to a percpu rwsem requires to prevent nested locking, so it's required to take the hotplug rwsem early in the call chain and establish a proper lock order. After quite some analysis and going down the wrong road severa times the following lock order has been chosen: kprobe_mutex -> cpus_rwsem -> jump_label_mutex -> text_mutex For kprobes which hook on an ftrace function trace point, it's required to drop cpus_rwsem before calling into the ftrace code to avoid a deadlock on the func_hash->regex_lock. [ Steven: Ftrace interaction fixes ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20170524081549.104864779@linutronix.de
| * | | jump_label: Reorder hotplug lock and jump_label_lockThomas Gleixner2017-05-265-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The conversion of the hotplug locking to a percpu rwsem unearthed lock ordering issues all over the place. The jump_label code has two issues: 1) Nested get_online_cpus() invocations 2) Ordering problems vs. the cpus rwsem and the jump_label_mutex To cure these, the following lock order has been established; cpus_rwsem -> jump_label_lock -> text_mutex Even if not all architectures need protection against CPU hotplug, taking cpus_rwsem before jump_label_lock is now mandatory in code pathes which actually modify code and therefor need text_mutex protection. Move the get_online_cpus() invocations into the core jump label code and establish the proper lock order where required. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Ralf Baechle <ralf@linux-mips.org> Link: http://lkml.kernel.org/r/20170524081549.025830817@linutronix.de
| * | | perf/tracing/cpuhotplug: Fix locking orderThomas Gleixner2017-05-262-30/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf, tracing, kprobes and jump_labels have a gazillion of ways to create dependency lock chains. Some of those involve nested invocations of get_online_cpus(). The conversion of the hotplug locking to a percpu rwsem requires to avoid such nested calls. sys_perf_event_open() protects most of the syscall logic against cpu hotplug. This causes nested calls and lock inversions versus ftrace and kprobes in various interesting ways. It's impossible to move the hotplug locking to the outer end of all call chains in the involved facilities, so the hotplug protection in sys_perf_event_open() needs to be solved differently. Introduce 'pmus_mutex' which protects a perf private online cpumask. This mutex is taken when the mask is updated in the cpu hotplug callbacks and can be taken in sys_perf_event_open() to protect the swhash setup/teardown code and when the final judgement about a valid event has to be made. [ tglx: Produced changelog and fixed the swhash interaction ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Link: http://lkml.kernel.org/r/20170524081548.930941109@linutronix.de
| * | | ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()Thomas Gleixner2017-05-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Converting the hotplug locking, i.e. get_online_cpus(), to a percpu rwsem unearthed a circular lock dependency which was hidden from lockdep due to the lockdep annotation of get_online_cpus() which prevents lockdep from creating full dependency chains. CPU0 CPU1 ---- ---- lock((&wfc.work)); lock(cpu_hotplug_lock.rw_sem); lock((&wfc.work)); lock(cpu_hotplug_lock.rw_sem); This dependency is established via acpi_processor_start() which calls into the work queue code. And the work queue code establishes the reverse dependency. This is not a problem of get_online_cpus() recursion, it's a possible deadlock undetected by lockdep so far. The cure is to use cpu_hotplug_disable() instead of get_online_cpus() to protect the probing from acpi_processor_start(). There is a side effect to this: cpu_hotplug_disable() makes a concurrent cpu hotplug attempt via the sysfs interfaces fail with -EBUSY, but that probing usually happens during the boot process where no interaction is possible. Any later invocations are infrequent enough and concurrent hotplug attempts are so unlikely that the danger of user space visible regressions is very close to zero. Anyway, thats preferrable over a real deadlock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-acpi@vger.kernel.org Cc: Len Brown <lenb@kernel.org> Link: http://lkml.kernel.org/r/20170524081548.851588594@linutronix.de
| * | | PCI: Replace the racy recursion preventionThomas Gleixner2017-05-262-22/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pci_call_probe() can called recursively when a physcial function is probed and the probing creates virtual functions, which are populated via pci_bus_add_device() which in turn can end up calling pci_call_probe() again. The code has an interesting way to prevent recursing into the workqueue code. That's accomplished by a check whether the current task runs already on the numa node which is associated with the device. While that works to prevent the recursion into the workqueue code, it's racy versus normal execution as there is no guarantee that the node does not vanish after the check. There is another issue with this code. It dereferences cpumask_of_node() unconditionally without checking whether the node is available. Make the detection reliable by: - Mark a probed device as 'is_probed' in pci_call_probe() - Check in pci_call_probe for a virtual function. If it's a virtual function and the associated physical function device is marked 'is_probed' then this is a recursive call, so the call can be invoked in the calling context. - Add a check whether the node is online before dereferencing it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-pci@vger.kernel.org Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081548.771457199@linutronix.de
| * | | PCI: Use cpu_hotplug_disable() instead of get_online_cpus()Thomas Gleixner2017-05-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Converting the hotplug locking, i.e. get_online_cpus(), to a percpu rwsem unearthed a circular lock dependency which was hidden from lockdep due to the lockdep annotation of get_online_cpus() which prevents lockdep from creating full dependency chains. There are several variants of this. And example is: Chain exists of: cpu_hotplug_lock.rw_sem --> drm_global_mutex --> &item->mutex CPU0 CPU1 ---- ---- lock(&item->mutex); lock(drm_global_mutex); lock(&item->mutex); lock(cpu_hotplug_lock.rw_sem); because there are dependencies through workqueues. The call chain is: get_online_cpus apply_workqueue_attrs __alloc_workqueue_key ttm_mem_global_init ast_ttm_mem_global_init drm_global_item_ref ast_mm_init ast_driver_load drm_dev_register drm_get_pci_dev ast_pci_probe local_pci_probe work_for_cpu_fn process_one_work worker_thread This is not a problem of get_online_cpus() recursion, it's a possible deadlock undetected by lockdep so far. The cure is to use cpu_hotplug_disable() instead of get_online_cpus() to protect the PCI probing. There is a side effect to this: cpu_hotplug_disable() makes a concurrent cpu hotplug attempt via the sysfs interfaces fail with -EBUSY, but PCI probing usually happens during the boot process where no interaction is possible. Any later invocations are infrequent enough and concurrent hotplug attempts are so unlikely that the danger of user space visible regressions is very close to zero. Anyway, thats preferrable over a real deadlock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-pci@vger.kernel.org Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081548.691198590@linutronix.de
| * | | perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()Sebastian Andrzej Siewior2017-05-261-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If intel_snb_check_microcode() is invoked via microcode_init -> perf_check_microcode -> intel_snb_check_microcode then get_online_cpus() is invoked nested. This works with the current implementation of get_online_cpus() but prevents converting it to a percpu rwsem. intel_snb_check_microcode() is also invoked from intel_sandybridge_quirk() unprotected. Drop get_online_cpus() from intel_snb_check_microcode() and add it to intel_sandybridge_quirk() so both call sites are protected. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20170524081548.594862191@linutronix.de
| * | | x86/perf: Drop EXPORT of perf_check_microcodeThomas Gleixner2017-05-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only caller is the microcode update, which cannot be modular. Drop the export. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20170524081548.515204988@linutronix.de
| * | | cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu()Sebastian Andrzej Siewior2017-05-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | takedown_cpu() is a cpu hotplug function invoking stop_machine(). The cpu hotplug machinery holds the hotplug lock for write. stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081548.423292433@linutronix.de
| * | | powerpc/powernv: Use stop_machine_cpuslocked()Sebastian Andrzej Siewior2017-05-261-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | set_subcores_per_core() holds get_online_cpus() while invoking stop_machine(). stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170524081548.331016542@linutronix.de
| * | | s390/kernel: Use stop_machine_cpuslocked()Sebastian Andrzej Siewior2017-05-261-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | stp_work_fn() holds get_online_cpus() while invoking stop_machine(). stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/20170524081548.250203087@linutronix.de
| * | | ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()Sebastian Andrzej Siewior2017-05-261-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | arch_hw_breakpoint_init() holds get_online_cpus() while registerring the hotplug callbacks. cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <linux@armlinux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081548.170940729@linutronix.de
| * | | perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked()Sebastian Andrzej Siewior2017-05-261-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | intel_cqm_init() holds get_online_cpus() while registerring the hotplug callbacks. cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081548.075604046@linutronix.de
| * | | hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()Sebastian Andrzej Siewior2017-05-261-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | etm_probe4() holds get_online_cpus() while invoking cpuhp_setup_state_nocalls(). cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081547.983493849@linutronix.de
| * | | hwtracing/coresight-etm3x: Use cpuhp_setup_state_nocalls_cpuslocked()Sebastian Andrzej Siewior2017-05-261-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | etm_probe() holds get_online_cpus() while invoking cpuhp_setup_state_nocalls(). cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081547.889092478@linutronix.de
| * | | KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls_cpuslocked()Sebastian Andrzej Siewior2017-05-261-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking cpuhp_setup_state_nocalls(). cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: kvm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: kvm-ppc@vger.kernel.org Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Alexander Graf <agraf@suse.com> Link: http://lkml.kernel.org/r/20170524081547.809616236@linutronix.de
| * | | cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked()Sebastian Andrzej Siewior2017-05-261-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpufreq holds get_online_cpus() while invoking cpuhp_setup_state_nocalls() to make subsys_interface_register() and the registration of hotplug calls atomic versus cpu hotplug. cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup/remove_state_nocalls_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081547.731628408@linutronix.de
| * | | x86/mtrr: Remove get_online_cpus() from mtrr_save_state()Sebastian Andrzej Siewior2017-05-261-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mtrr_save_state() is invoked from native_cpu_up() which is in the context of a CPU hotplug operation and therefor calling get_online_cpus() is pointless. While this works in the current get_online_cpus() implementation it prevents from converting the hotplug locking to percpu rwsems. Remove it. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081547.651378834@linutronix.de
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