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Reinette Chatre 93e2d845f2 x86/intel_rdt: Fix potential deadlock during resctrl unmount ... [ Upstream commit 36b6f9fcb8 ] Lockdep warns about a potential deadlock: [ 66.782842] ====================================================== [ 66.782888] WARNING: possible circular locking dependency detected [ 66.782937] 4.14.0-rc2-test-test+ #48 Not tainted [ 66.782983] ------------------------------------------------------ [ 66.783052] umount/336 is trying to acquire lock: [ 66.783117] (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff81032395>] rdt_kill_sb+0x215/0x390 [ 66.783193] but task is already holding lock: [ 66.783244] (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 [ 66.783305] which lock already depends on the new lock. [ 66.783364] the existing dependency chain (in reverse order) is: [ 66.783419] -> #3 (rdtgroup_mutex){+.+.}: [ 66.783467] __lock_acquire+0x1293/0x13f0 [ 66.783509] lock_acquire+0xaf/0x220 [ 66.783543] __mutex_lock+0x71/0x9b0 [ 66.783575] mutex_lock_nested+0x1b/0x20 [ 66.783610] intel_rdt_online_cpu+0x3b/0x430 [ 66.783649] cpuhp_invoke_callback+0xab/0x8e0 [ 66.783687] cpuhp_thread_fun+0x7a/0x150 [ 66.783722] smpboot_thread_fn+0x1cc/0x270 [ 66.783764] kthread+0x16e/0x190 [ 66.783794] ret_from_fork+0x27/0x40 [ 66.783825] -> #2 (cpuhp_state){+.+.}: [ 66.783870] __lock_acquire+0x1293/0x13f0 [ 66.783906] lock_acquire+0xaf/0x220 [ 66.783938] cpuhp_issue_call+0x102/0x170 [ 66.783974] __cpuhp_setup_state_cpuslocked+0x154/0x2a0 [ 66.784023] __cpuhp_setup_state+0xc7/0x170 [ 66.784061] page_writeback_init+0x43/0x67 [ 66.784097] pagecache_init+0x43/0x4a [ 66.784131] start_kernel+0x3ad/0x3f7 [ 66.784165] x86_64_start_reservations+0x2a/0x2c [ 66.784204] x86_64_start_kernel+0x72/0x75 [ 66.784241] verify_cpu+0x0/0xfb [ 66.784270] -> #1 (cpuhp_state_mutex){+.+.}: [ 66.784319] __lock_acquire+0x1293/0x13f0 [ 66.784355] lock_acquire+0xaf/0x220 [ 66.784387] __mutex_lock+0x71/0x9b0 [ 66.784419] mutex_lock_nested+0x1b/0x20 [ 66.784454] __cpuhp_setup_state_cpuslocked+0x52/0x2a0 [ 66.784497] __cpuhp_setup_state+0xc7/0x170 [ 66.784535] page_alloc_init+0x28/0x30 [ 66.784569] start_kernel+0x148/0x3f7 [ 66.784602] x86_64_start_reservations+0x2a/0x2c [ 66.784642] x86_64_start_kernel+0x72/0x75 [ 66.784678] verify_cpu+0x0/0xfb [ 66.784707] -> #0 (cpu_hotplug_lock.rw_sem){++++}: [ 66.784759] check_prev_add+0x32f/0x6e0 [ 66.784794] __lock_acquire+0x1293/0x13f0 [ 66.784830] lock_acquire+0xaf/0x220 [ 66.784863] cpus_read_lock+0x3d/0xb0 [ 66.784896] rdt_kill_sb+0x215/0x390 [ 66.784930] deactivate_locked_super+0x3e/0x70 [ 66.784968] deactivate_super+0x40/0x60 [ 66.785003] cleanup_mnt+0x3f/0x80 [ 66.785034] __cleanup_mnt+0x12/0x20 [ 66.785070] task_work_run+0x8b/0xc0 [ 66.785103] exit_to_usermode_loop+0x94/0xa0 [ 66.786804] syscall_return_slowpath+0xe8/0x150 [ 66.788502] entry_SYSCALL_64_fastpath+0xab/0xad [ 66.790194] other info that might help us debug this: [ 66.795139] Chain exists of: cpu_hotplug_lock.rw_sem --> cpuhp_state --> rdtgroup_mutex [ 66.800035] Possible unsafe locking scenario: [ 66.803267] CPU0 CPU1 [ 66.804867] ---- ---- [ 66.806443] lock(rdtgroup_mutex); [ 66.808002] lock(cpuhp_state); [ 66.809565] lock(rdtgroup_mutex); [ 66.811110] lock(cpu_hotplug_lock.rw_sem); [ 66.812608] *** DEADLOCK *** [ 66.816983] 2 locks held by umount/336: [ 66.818418] #0: (&type->s_umount_key#35){+.+.}, at: [<ffffffff81229738>] deactivate_super+0x38/0x60 [ 66.819922] #1: (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 When the resctrl filesystem is unmounted the locks should be obtain in the locks in the same order as was done when the cpus came online: cpu_hotplug_lock before rdtgroup_mutex. This also requires to switch the static_branch_disable() calls to the _cpulocked variant because now cpu hotplug lock is held already. [ tglx: Switched to cpus_read_[un]lock ] Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Acked-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Acked-by: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/cc292e76be073f7260604651711c47b09fd0dc81.1508490116.git.reinette.chatre@intel.com Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2017-12-17 15:08:01 +01:00
..
boot	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
configs	Merge branch 'x86/urgent' into x86/asm, to pick up fixes	2017-08-10 13:14:15 +02:00
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2017-11-06 09:05:03 -08:00
entry	Revert "x86/entry/64: Add missing irqflags tracing to native_load_gs_index()"	2017-12-05 11:26:38 +01:00
events	perf/x86/intel: Hide TSX events when RTM is not supported	2017-11-30 08:40:40 +00:00
hyperv	x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing	2017-10-10 12:54:56 +02:00
ia32	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
include	fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscall	2017-12-17 15:07:59 +01:00
kernel	x86/intel_rdt: Fix potential deadlock during resctrl unmount	2017-12-17 15:08:01 +01:00
kvm	KVM: VMX: remove I/O port 0x80 bypass on Intel hosts	2017-12-14 09:53:01 +01:00
lib	x86/decoder: Add new TEST instruction pattern	2017-11-30 08:40:39 +00:00
math-emu	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
mm	locking/refcounts: Do not force refcount_t usage as GPL-only export	2017-12-10 13:40:45 +01:00
net	bpf: fix bpf_tail_call() x64 JIT	2017-10-03 16:04:44 -07:00
oprofile	x86/oprofile/ppro: Do not use __this_cpu*() in preemptible context	2017-11-08 13:01:54 +01:00
pci	x86/PCI: Make broadcom_postcore_init() check acpi_disabled	2017-12-14 09:52:53 +01:00
platform	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
power	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
purgatory	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
ras	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
realmode	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
tools	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
um	x86/entry: Use SYSCALL_DEFINE() macros for sys_modify_ldt()	2017-12-10 13:40:41 +01:00
video	x86/video: Don't assume all FB devices are PCI devices	2016-03-15 11:08:26 +01:00
xen	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
.gitignore	x86/build: Add arch/x86/purgatory/ make generated files to gitignore	2014-10-09 09:29:46 +02:00
Kbuild	Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-09-07 09:25:15 -07:00
Kconfig	locking/refcounts, x86/asm: Enable CONFIG_ARCH_HAS_REFCOUNT	2017-12-10 13:40:43 +01:00
Kconfig.cpu	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Kconfig.debug	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Makefile.um	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Makefile_32.cpu	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00