BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
1 lock held by perf/342:
#0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
irq event stamp: 62224
hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
softirqs last disabled at (0): [< (null)>] (null)
CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffffffc000089968>] dump_backtrace+0x0/0x128
[<ffffffc000089ab0>] show_stack+0x20/0x30
[<ffffffc0007030d0>] dump_stack+0x7c/0xa0
[<ffffffc0000c878c>] ___might_sleep+0x174/0x260
[<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
[<ffffffc000708db0>] rt_read_lock+0x60/0x80
[<ffffffc0000851a8>] call_break_hook+0x30/0xd0
[<ffffffc000085a70>] brk_handler+0x30/0x98
[<ffffffc000082248>] do_debug_exception+0x50/0xb8
Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
fe20: 00000000 00000000 c1594680 0000007f
fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
ff40: 928e4cc0 0000007f 91ff11e8 0000007f
call_break_hook is called in atomic context (hard irq disabled), so replace
the sleepable lock to rcu lock, replace relevant list operations to rcu
version and call synchronize_rcu() in unregister_break_hook().
And, replace write lock to spinlock in {un}register_break_hook.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Fix comment typo: s/handers/handlers/ Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
We have a couple of CPU hotplug notifiers for resetting the CPU debug state to a sane value when a CPU comes online. This patch ensures that we mask out CPU_TASKS_FROZEN so that we don't miss any online events occuring due to suspend/resume. Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
lib/list_sort.c defines a 'struct debug_el', where "el" is assumedly a a contraction of "element". This conflicts with 'enum debug_el' in our asm/debug-monitors.h header file, where "el" stands for Exception Level. The result is build failure when targetting allmodconfig, so rename our enum to 'dbg_active_el' to be slightly more explicit about what it is. Signed-off-by: Will Deacon <will.deacon@arm.com>
KVM/ARM New features for 3.17 include: - Fixes and code refactoring for stage2 kvm MMU unmap_range - Support unmapping IPAs on deleting memslots for arm and arm64 - Support MMIO mappings in stage2 faults - KVM VGIC v2 emulation on GICv3 hardware - Big-Endian support for arm/arm64 (guest and host) - Debug Architecture support for arm64 (arm32 is on Christoffer's todo list) Conflicts: virt/kvm/arm/vgic.c [last minute cherry-pick from 3.17 to 3.16]
Our break hooks are used to handle brk exceptions from kgdb (and potentially kprobes if that code ever resurfaces), so don't bother calling them if the BRK exception comes from userspace. This prevents userspace from trapping to a kdb shell on systems where kgdb is enabled and active. Cc: <stable@vger.kernel.org> Reported-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
In order to be able to use the DBG_MDSCR_* macros from the KVM code, move the relevant definitions to the obvious include file. Also move the debug_el enum to a portion of the file that is guarded by #ifndef __ASSEMBLY__ in order to use that file from assembly code. Acked-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Sending a SIGTRAP to a user task after execution of a BRK instruction at EL0 is fundamental to the way in which software breakpoints work and doesn't deserve a warning to be logged in dmesg. Whilst the warning can be justified from EL1, do_debug_exception will already do the right thing, so simply remove the code altogether. Cc: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> Reported-by: Kyrylo Tkachov <kyrylo.tkachov@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
"The purpose of this single series of commits from Srivatsa S Bhat
(with a small piece from Gautham R Shenoy) touching multiple
subsystems that use CPU hotplug notifiers is to provide a way to
register them that will not lead to deadlocks with CPU online/offline
operations as described in the changelog of commit 93ae4f978ca7f ("CPU
hotplug: Provide lockless versions of callback registration
functions").
The first three commits in the series introduce the API and document
it and the rest simply goes through the users of CPU hotplug notifiers
and converts them to using the new method"
* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
net/iucv/iucv.c: Fix CPU hotplug callback registration
net/core/flow.c: Fix CPU hotplug callback registration
mm, zswap: Fix CPU hotplug callback registration
mm, vmstat: Fix CPU hotplug callback registration
profile: Fix CPU hotplug callback registration
trace, ring-buffer: Fix CPU hotplug callback registration
xen, balloon: Fix CPU hotplug callback registration
hwmon, via-cputemp: Fix CPU hotplug callback registration
hwmon, coretemp: Fix CPU hotplug callback registration
thermal, x86-pkg-temp: Fix CPU hotplug callback registration
octeon, watchdog: Fix CPU hotplug callback registration
oprofile, nmi-timer: Fix CPU hotplug callback registration
intel-idle: Fix CPU hotplug callback registration
clocksource, dummy-timer: Fix CPU hotplug callback registration
drivers/base/topology.c: Fix CPU hotplug callback registration
acpi-cpufreq: Fix CPU hotplug callback registration
zsmalloc: Fix CPU hotplug callback registration
scsi, fcoe: Fix CPU hotplug callback registration
scsi, bnx2fc: Fix CPU hotplug callback registration
scsi, bnx2i: Fix CPU hotplug callback registration
...
Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the debug-monitors code in arm64 by using this latter form of callback registration. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Ingo Molnar <mingo@kernel.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>