Reinette Chatre 6c5faa4456 x86/intel_rdt: Fix potential deadlock during resctrl mount ... [ Upstream commit 87943db7df ] Sai reported a warning during some MBA tests: [ 236.755559] ====================================================== [ 236.762443] WARNING: possible circular locking dependency detected [ 236.769328] 4.14.0-rc4-yocto-standard #8 Not tainted [ 236.774857] ------------------------------------------------------ [ 236.781738] mount/10091 is trying to acquire lock: [ 236.787071] (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff8117f892>] static_key_enable+0x12/0x30 [ 236.797058] but task is already holding lock: [ 236.803552] (&type->s_umount_key#37/1){+.+.}, at: [<ffffffff81208b2f>] sget_userns+0x32f/0x520 [ 236.813247] which lock already depends on the new lock. [ 236.822353] the existing dependency chain (in reverse order) is: [ 236.830686] -> #4 (&type->s_umount_key#37/1){+.+.}: [ 236.837756] __lock_acquire+0x1100/0x11a0 [ 236.842799] lock_acquire+0xdf/0x1d0 [ 236.847363] down_write_nested+0x46/0x80 [ 236.852310] sget_userns+0x32f/0x520 [ 236.856873] kernfs_mount_ns+0x7e/0x1f0 [ 236.861728] rdt_mount+0x30c/0x440 [ 236.866096] mount_fs+0x38/0x150 [ 236.870262] vfs_kern_mount+0x67/0x150 [ 236.875015] do_mount+0x1df/0xd50 [ 236.879286] SyS_mount+0x95/0xe0 [ 236.883464] entry_SYSCALL_64_fastpath+0x18/0xad [ 236.889183] -> #3 (rdtgroup_mutex){+.+.}: [ 236.895292] __lock_acquire+0x1100/0x11a0 [ 236.900337] lock_acquire+0xdf/0x1d0 [ 236.904899] __mutex_lock+0x80/0x8f0 [ 236.909459] mutex_lock_nested+0x1b/0x20 [ 236.914407] intel_rdt_online_cpu+0x3b/0x4a0 [ 236.919745] cpuhp_invoke_callback+0xce/0xb80 [ 236.925177] cpuhp_thread_fun+0x1c5/0x230 [ 236.930222] smpboot_thread_fn+0x11a/0x1e0 [ 236.935362] kthread+0x152/0x190 [ 236.939536] ret_from_fork+0x27/0x40 [ 236.944097] -> #2 (cpuhp_state-up){+.+.}: [ 236.950199] __lock_acquire+0x1100/0x11a0 [ 236.955241] lock_acquire+0xdf/0x1d0 [ 236.959800] cpuhp_issue_call+0x12e/0x1c0 [ 236.964845] __cpuhp_setup_state_cpuslocked+0x13b/0x2f0 [ 236.971242] __cpuhp_setup_state+0xa7/0x120 [ 236.976483] page_writeback_init+0x43/0x67 [ 236.981623] pagecache_init+0x38/0x3b [ 236.986281] start_kernel+0x3c6/0x41a [ 236.990931] x86_64_start_reservations+0x2a/0x2c [ 236.996650] x86_64_start_kernel+0x72/0x75 [ 237.001793] verify_cpu+0x0/0xfb [ 237.005966] -> #1 (cpuhp_state_mutex){+.+.}: [ 237.012364] __lock_acquire+0x1100/0x11a0 [ 237.017408] lock_acquire+0xdf/0x1d0 [ 237.021969] __mutex_lock+0x80/0x8f0 [ 237.026527] mutex_lock_nested+0x1b/0x20 [ 237.031475] __cpuhp_setup_state_cpuslocked+0x54/0x2f0 [ 237.037777] __cpuhp_setup_state+0xa7/0x120 [ 237.043013] page_alloc_init+0x28/0x30 [ 237.047769] start_kernel+0x148/0x41a [ 237.052425] x86_64_start_reservations+0x2a/0x2c [ 237.058145] x86_64_start_kernel+0x72/0x75 [ 237.063284] verify_cpu+0x0/0xfb [ 237.067456] -> #0 (cpu_hotplug_lock.rw_sem){++++}: [ 237.074436] check_prev_add+0x401/0x800 [ 237.079286] __lock_acquire+0x1100/0x11a0 [ 237.084330] lock_acquire+0xdf/0x1d0 [ 237.088890] cpus_read_lock+0x42/0x90 [ 237.093548] static_key_enable+0x12/0x30 [ 237.098496] rdt_mount+0x406/0x440 [ 237.102862] mount_fs+0x38/0x150 [ 237.107035] vfs_kern_mount+0x67/0x150 [ 237.111787] do_mount+0x1df/0xd50 [ 237.116058] SyS_mount+0x95/0xe0 [ 237.120233] entry_SYSCALL_64_fastpath+0x18/0xad [ 237.125952] other info that might help us debug this: [ 237.134867] Chain exists of: cpu_hotplug_lock.rw_sem --> rdtgroup_mutex --> &type->s_umount_key#37/1 [ 237.148425] Possible unsafe locking scenario: [ 237.155015] CPU0 CPU1 [ 237.160057] ---- ---- [ 237.165100] lock(&type->s_umount_key#37/1); [ 237.169952] lock(rdtgroup_mutex); [ 237.176641] lock(&type->s_umount_key#37/1); [ 237.184287] lock(cpu_hotplug_lock.rw_sem); [ 237.189041] *** DEADLOCK *** When the resctrl filesystem is mounted the locks must be acquired 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_enable() calls to the _cpulocked variant because now cpu hotplug lock is held already. [ tglx: Switched to cpus_read_[un]lock ] Reported-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Acked-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Link: https://lkml.kernel.org/r/9c41b91bc2f47d9e95b62b213ecdb45623c47a9f.1508490116.git.reinette.chatre@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-12-10 13:40:40 +01:00
..
alpha	License cleanup: add SPDX license identifiers to some files	2017-11-02 10:04:46 -07:00
arc	License cleanup: add SPDX license identifiers to some files	2017-11-02 10:04:46 -07:00
arm	ARM: 8721/1: mm: dump: check hardware RO bit for LPAE	2017-11-30 08:40:40 +00:00
arm64	arm64: ftrace: emit ftrace-mod.o contents through code	2017-12-05 11:26:31 +01:00
blackfin	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
c6x	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
cris	License cleanup: add SPDX license identifier to uapi header files with no license	2017-11-02 11:19:54 +01:00
frv	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
h8300	License cleanup: add SPDX license identifier to uapi header files with no license	2017-11-02 11:19:54 +01:00
hexagon	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
ia64	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-05 12:14:50 -08:00
m32r	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
m68k	m68k: fix ColdFire node shift size calculation	2017-12-10 13:40:39 +01:00
metag	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
microblaze	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
mips	MIPS: Add custom serial.h with BASE_BAUD override for generic kernel	2017-12-10 13:40:38 +01:00
mn10300	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
nios2	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
openrisc	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
parisc	parisc: Fix validity check of pointer size argument in new CAS implementation	2017-11-30 08:40:56 +00:00
powerpc	powerpc/kexec: Fix kexec/kdump in P9 guest kernels	2017-12-05 11:26:31 +01:00
s390	s390/pci: do not require AIS facility	2017-12-10 13:40:38 +01:00
score	License cleanup: add SPDX license identifier to uapi header files with no license	2017-11-02 11:19:54 +01:00
sh	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
sparc	sparc64: Fix page table walk for PUD hugepages	2017-11-21 09:49:25 +01:00
tile	Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile	2017-11-03 10:36:43 -07:00
um	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
unicore32	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
x86	x86/intel_rdt: Fix potential deadlock during resctrl mount	2017-12-10 13:40:40 +01:00
xtensa	License cleanup: add SPDX license identifier to uapi header files with a license	2017-11-02 11:20:11 +01:00
.gitignore	…
Kconfig	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00