| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
kvm_arch_prepare_memory_region
In kvm_arch_prepare_memory_region, arm kvm regards the memory region as
writable if the flag has no KVM_MEM_READONLY, and the vm is readonly if
!VM_WRITE.
But there is common usage for setting kvm memory region as follows:
e.g. qemu side (see the PROT_NONE flag)
1. mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
memory_region_init_ram_ptr()
2. re mmap the above area with read/write authority.
Such example is used in virtio-fs qemu codes which hasn't been upstreamed
[1]. But seems we can't forbid this example.
Without this patch, it will cause an EPERM during kvm_set_memory_region()
and cause qemu boot crash.
As told by Ard, "the underlying assumption is incorrect, i.e., that the
value of vm_flags at this point in time defines how the VMA is used
during its lifetime. There may be other cases where a VMA is created
with VM_READ vm_flags that are changed to VM_READ|VM_WRITE later, and
we are currently rejecting this use case as well."
[1] https://gitlab.com/virtio-fs/qemu/blob/5a356e/hw/virtio/vhost-user-fs.c#L488
Suggested-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Jia He <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
We don't intend to support IMPLEMENATION DEFINED system registers, but
have to trap them (and emulate them as UNDEFINED). These traps aren't
interesting to the system administrator or to the KVM developers, so
let's not bother logging when we do so.
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
Currently kvm_pr_unimpl() is ratelimited, so print_sys_reg_instr() won't
spam the console. However, someof its callers try to print some
contextual information with kvm_err(), which is not ratelimited. This
means that in some cases the context may be printed without the sysreg
encoding, which isn't all that useful.
Let's ensure that both are consistently printed together and
ratelimited, by refactoring print_sys_reg_instr() so that some callers
can provide it with an arbitrary format string.
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
kvm_vgic_create()
Use wrapper function lock_all_vcpus()/unlock_all_vcpus()
in kvm_vgic_create() to remove duplicated code dealing
with locking and unlocking all vcpus in a vm.
Signed-off-by: Miaohe Lin <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Reviewed-by: Steven Price <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
__kvm_vgic_destroy()
In kvm_vgic_dist_init() called from kvm_vgic_map_resources(), if
dist->vgic_model is invalid, dist->spis will be freed without set
dist->spis = NULL. And in vgicv2 resources clean up path,
__kvm_vgic_destroy() will be called to free allocated resources.
And dist->spis will be freed again in clean up chain because we
forget to set dist->spis = NULL in kvm_vgic_dist_init() failed
path. So double free would happen.
Signed-off-by: Miaohe Lin <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
As arg dummy is not really needed, there's no need to pass
NULL when calling cpu_init_hyp_mode(). So clean it up.
Fixes: 67f691976662 ("arm64: kvm: allows kvm cpu hotplug")
Reviewed-by: Steven Price <[email protected]>
Signed-off-by: Miaohe Lin <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
|
|
injection
Just like we do for WFE trapping, it can be useful to turn off
WFI trapping when the physical CPU is not oversubscribed (that
is, the vcpu is the only runnable process on this CPU) *and*
that we're using direct injection of interrupts.
The conditions are reevaluated on each vcpu_load(), ensuring that
we don't switch to this mode on a busy system.
On a GICv4 system, this has the effect of reducing the generation
of doorbell interrupts to zero when the right conditions are
met, which is a huge improvement over the current situation
(where the doorbells are screaming if the CPU ever hits a
blocking WFI).
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Zenghui Yu <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
In order to find out whether a vcpu is likely to be the target of
VLPIs (and to further optimize the way we deal with those), let's
track the number of VLPIs a vcpu can receive.
This gets implemented with an atomic variable that gets incremented
or decremented on map, unmap and move of a VLPI.
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Zenghui Yu <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
The timers are canceled from an preempt-notifier which is invoked with
disabled preemption which is not allowed on PREEMPT_RT.
The timer callback is short so in could be invoked in hard-IRQ context
on -RT.
Let the timer expire on hard-IRQ context even on -RT.
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Tested-by: Julien Grall <[email protected]>
Acked-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
It's possible that two LPIs locate in the same "byte_offset" but target
two different vcpus, where their pending status are indicated by two
different pending tables. In such a scenario, using last_byte_offset
optimization will lead KVM relying on the wrong pending table entry.
Let us use last_ptr instead, which can be treated as a byte index into
a pending table and also, can be vcpu specific.
Fixes: 280771252c1b ("KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES")
Cc: [email protected]
Signed-off-by: Zenghui Yu <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Acked-by: Eric Auger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
Fix various comments, including wrong function names, grammar mistakes
and specification references.
Signed-off-by: Zenghui Yu <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
The callsite of kvm_send_userspace_msi() is currently arch agnostic.
There seems no reason to keep an extra declaration of it in arm_vgic.h
(we already have one in include/linux/kvm_host.h).
Remove it.
Signed-off-by: Zenghui Yu <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
When the VHE code was reworked, a lot of the vgic stuff was moved around,
but the GICv4 residency code did stay untouched, meaning that we come
in and out of residency on each flush/sync, which is obviously suboptimal.
To address this, let's move things around a bit:
- Residency entry (flush) moves to vcpu_load
- Residency exit (sync) moves to vcpu_put
- On blocking (entry to WFI), we "put"
- On unblocking (exit from WFI), we "load"
Because these can nest (load/block/put/load/unblock/put, for example),
we now have per-VPE tracking of the residency state.
Additionally, vgic_v4_put gains a "need doorbell" parameter, which only
gets set to true when blocking because of a WFI. This allows a finer
control of the doorbell, which now also gets disabled as soon as
it gets signaled.
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
On CPUs that support S2FWB (Armv8.4+), KVM configures the stage 2 page
tables to override the memory attributes of memory accesses, regardless
of the stage 1 page table configurations, and also when the stage 1 MMU
is turned off. This results in all memory accesses to RAM being
cacheable, including during early boot of the guest.
On CPUs without this feature, memory accesses were non-cacheable during
boot until the guest turned on the stage 1 MMU, and we had to detect
when the guest turned on the MMU, such that we could invalidate all cache
entries and ensure a consistent view of memory with the MMU turned on.
When the guest turned on the caches, we would call stage2_flush_vm()
from kvm_toggle_cache().
However, stage2_flush_vm() walks all the stage 2 tables, and calls
__kvm_flush-dcache_pte, which on a system with S2FWB does ... absolutely
nothing.
We can avoid that whole song and dance, and simply not set TVM when
creating a VM on a system that has S2FWB.
Signed-off-by: Christoffer Dall <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Mark Rutland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
ARM/ARM64 has counters halt_successful_poll, halt_attempted_poll,
halt_poll_invalid, and halt_wakeup but never exposed those in debugfs.
Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
|
|
kvmarm-master/next
|
|
SCHEDSTATS requires DEBUG_KERNEL (and PROC_FS) and therefore isn't a
good choice for enabling the scheduling statistics required for stolen
time.
Instead match the x86 configuration and select TASK_DELAY_ACCT and
TASKSTATS. This adds the dependencies of NET && MULTIUSER for arm64 KVM.
Suggested-by: Marc Zyngier <[email protected]>
Fixes: 8564d6372a7d ("KVM: arm64: Support stolen time reporting via shared structure")
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Enable paravirtualization features when running under a hypervisor
supporting the PV_TIME_ST hypercall.
For each (v)CPU, we ask the hypervisor for the location of a shared
page which the hypervisor will use to report stolen time to us. We set
pv_time_ops to the stolen time function which simply reads the stolen
value from the shared page for a VCPU. We guarantee single-copy
atomicity using READ_ONCE which means we can also read the stolen
time for another VCPU than the currently running one while it is
potentially being updated by the hypervisor.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Rather than directly choosing which function to use based on
psci_ops.conduit, use the new arm_smccc_1_1 wrapper instead.
In some cases we still need to do some operations based on the
conduit, but the code duplication is removed.
No functional change.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
SMCCC 1.1 calls may use either HVC or SMC depending on the PSCI
conduit. Rather than coding this in every call site, provide a macro
which uses the correct instruction. The macro also handles the case
where no conduit is configured/available returning a not supported error
in res, along with returning the conduit used for the call.
This allow us to remove some duplicated code and will be useful later
when adding paravirtualized time hypervisor calls.
Signed-off-by: Steven Price <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Allow user space to inform the KVM host where in the physical memory
map the paravirtualized time structures should be located.
User space can set an attribute on the VCPU providing the IPA base
address of the stolen time structure for that VCPU. This must be
repeated for every VCPU in the VM.
The address is given in terms of the physical address visible to
the guest and must be 64 byte aligned. The guest will discover the
address via a hypercall.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Currently a kvm_device_ops structure cannot be const without triggering
compiler warnings. However the structure doesn't need to be written to
and, by marking it const, it can be read-only in memory. Add some more
const keywords to allow this.
Reviewed-by: Andrew Jones <[email protected]>
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Implement the service call for configuring a shared structure between a
VCPU and the hypervisor in which the hypervisor can write the time
stolen from the VCPU's execution time by other tasks on the host.
User space allocates memory which is placed at an IPA also chosen by user
space. The hypervisor then updates the shared structure using
kvm_put_guest() to ensure single copy atomicity of the 64-bit value
reporting the stolen time in nanoseconds.
Whenever stolen time is enabled by the guest, the stolen time counter is
reset.
The stolen time itself is retrieved from the sched_info structure
maintained by the Linux scheduler code. We enable SCHEDSTATS when
selecting KVM Kconfig to ensure this value is meaningful.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
kvm_put_guest() is analogous to put_user() - it writes a single value to
the guest physical address. The implementation is built upon put_user()
and so it has the same single copy atomic properties.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
This provides a mechanism for querying which paravirtualized time
features are available in this hypervisor.
Also add the header file which defines the ABI for the paravirtualized
time features we're about to add.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
We currently intertwine the KVM PSCI implementation with the general
dispatch of hypercall handling, which makes perfect sense because PSCI
is the only category of hypercalls we support.
However, as we are about to support additional hypercalls, factor out
this functionality into a separate hypercall handler file.
Signed-off-by: Christoffer Dall <[email protected]>
[[email protected]: rebased]
Reviewed-by: Andrew Jones <[email protected]>
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Introduce a paravirtualization interface for KVM/arm64 based on the
"Arm Paravirtualized Time for Arm-Base Systems" specification DEN 0057A.
This only adds the details about "Stolen Time" as the details of "Live
Physical Time" have not been fully agreed.
User space can specify a reserved area of memory for the guest and
inform KVM to populate the memory with information on time that the host
kernel has stolen from the guest.
A hypercall interface is provided for the guest to interrogate the
hypervisor's support for this interface and the location of the shared
memory structures.
Signed-off-by: Steven Price <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
kvm-arm64/stolen-time
|
|
In some scenarios, such as buggy guest or incorrect configuration of the
VMM and firmware description data, userspace will detect a memory access
to a portion of the IPA, which is not mapped to any MMIO region.
For this purpose, the appropriate action is to inject an external abort
to the guest. The kernel already has functionality to inject an
external abort, but we need to wire up a signal from user space that
lets user space tell the kernel to do this.
It turns out, we already have the set event functionality which we can
perfectly reuse for this.
Signed-off-by: Christoffer Dall <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
For a long time, if a guest accessed memory outside of a memslot using
any of the load/store instructions in the architecture which doesn't
supply decoding information in the ESR_EL2 (the ISV bit is not set), the
kernel would print the following message and terminate the VM as a
result of returning -ENOSYS to userspace:
load/store instruction decoding not implemented
The reason behind this message is that KVM assumes that all accesses
outside a memslot is an MMIO access which should be handled by
userspace, and we originally expected to eventually implement some sort
of decoding of load/store instructions where the ISV bit was not set.
However, it turns out that many of the instructions which don't provide
decoding information on abort are not safe to use for MMIO accesses, and
the remaining few that would potentially make sense to use on MMIO
accesses, such as those with register writeback, are not used in
practice. It also turns out that fetching an instruction from guest
memory can be a pretty horrible affair, involving stopping all CPUs on
SMP systems, handling multiple corner cases of address translation in
software, and more. It doesn't appear likely that we'll ever implement
this in the kernel.
What is much more common is that a user has misconfigured his/her guest
and is actually not accessing an MMIO region, but just hitting some
random hole in the IPA space. In this scenario, the error message above
is almost misleading and has led to a great deal of confusion over the
years.
It is, nevertheless, ABI to userspace, and we therefore need to
introduce a new capability that userspace explicitly enables to change
behavior.
This patch introduces KVM_CAP_ARM_NISV_TO_USER (NISV meaning Non-ISV)
which does exactly that, and introduces a new exit reason to report the
event to userspace. User space can then emulate an exception to the
guest, restart the guest, suspend the guest, or take any other
appropriate action as per the policy of the running system.
Reported-by: Heinrich Schuchardt <[email protected]>
Signed-off-by: Christoffer Dall <[email protected]>
Reviewed-by: Alexander Graf <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
|
|
Now that we have common definitions for SMCCC conduits, move the SDEI
code over to them, and remove the SDEI-specific definitions.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <[email protected]>
Acked-by: Lorenzo Pieralisi <[email protected]>
Acked-by: James Morse <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
|
|
Now that we have common SMCCC_CONDUIT_* definitions, migrate the PSCI
code over to them, and kill off the old PSCI_CONDUIT_* definitions.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <[email protected]>
Acked-by: Lorenzo Pieralisi <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
|
|
Now that we have arm_smccc_1_1_get_conduit(), we can hide the PSCI
implementation details from the arm spectre-v2 code, so let's do so.
As arm_smccc_1_1_get_conduit() implicitly checks that the SMCCC version
is at least SMCCC_VERSION_1_1, we no longer need to check this
explicitly where switch statements have a default case.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Russell King <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
|
|
Now that we have arm_smccc_1_1_get_conduit(), we can hide the PSCI
implementation details from the arm64 cpu errata code, so let's do so.
As arm_smccc_1_1_get_conduit() implicitly checks that the SMCCC version
is at least SMCCC_VERSION_1_1, we no longer need to check this
explicitly where switch statements have a default case, e.g. in
has_ssbd_mitigation().
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
|
|
SMCCC callers are currently amassing a collection of enums for the SMCCC
conduit, and are having to dig into the PSCI driver's internals in order
to figure out what to do.
Let's clean this up, with common SMCCC_CONDUIT_* definitions, and an
arm_smccc_1_1_get_conduit() helper that abstracts the PSCI driver's
internal state.
We can kill off the PSCI_CONDUIT_* definitions once we've migrated users
over to the new interface.
Signed-off-by: Mark Rutland <[email protected]>
Acked-by: Lorenzo Pieralisi <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
|
|
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"A few tracing fixes:
- Remove lockdown from tracefs itself and moved it to the trace
directory. Have the open functions there do the lockdown checks.
- Fix a few races with opening an instance file and the instance
being deleted (Discovered during the lockdown updates). Kept
separate from the clean up code such that they can be backported to
stable easier.
- Clean up and consolidated the checks done when opening a trace
file, as there were multiple checks that need to be done, and it
did not make sense having them done in each open instance.
- Fix a regression in the record mcount code.
- Small hw_lat detector tracer fixes.
- A trace_pipe read fix due to not initializing trace_seq"
* tag 'trace-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Initialize iter->seq after zeroing in tracing_read_pipe()
tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
tracing/hwlat: Report total time spent in all NMIs during the sample
recordmcount: Fix nop_mcount() function
tracing: Do not create tracefs files if tracefs lockdown is in effect
tracing: Add locked_down checks to the open calls of files created for tracefs
tracing: Add tracing_check_open_get_tr()
tracing: Have trace events system open call tracing_open_generic_tr()
tracing: Get trace_array reference for available_tracers files
ftrace: Get a reference counter for the trace_array on filter files
tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down")
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon fixes from Guenter Roeck:
- Update/fix inspur-ipsps1 and k10temp Documentation
- Fix nct7904 driver
- Fix HWMON_P_MIN_ALARM mask in hwmon core
* tag 'hwmon-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: docs: Extend inspur-ipsps1 title underline
hwmon: (nct7904) Add array fan_alarm and vsen_alarm to store the alarms in nct7904_data struct.
docs: hwmon: Include 'inspur-ipsps1.rst' into docs
hwmon: Fix HWMON_P_MIN_ALARM mask
hwmon: (k10temp) Update documentation and add temp2_input info
hwmon: (nct7904) Fix the incorrect value of vsen_mask in nct7904_data struct
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux
Pull MTD fixes from Richard Weinberger:
"Two fixes for MTD:
- spi-nor: Fix for a regression in write_sr()
- rawnand: Regression fix for the au1550nd driver"
* tag 'fixes-for-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
mtd: rawnand: au1550nd: Fix au_read_buf16() prototype
mtd: spi-nor: Fix direction of the write_sr() transfer
|
|
Pull io_uring fix from Jens Axboe:
"Single small fix for a regression in the sequence logic for linked
commands"
* tag 'for-linus-20191012' of git://git.kernel.dk/linux-block:
io_uring: fix sequence logic for timeout requests
|
|
A customer reported the following softlockup:
[899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464]
[899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] Kernel panic - not syncing: softlockup: hung tasks
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12
[899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000
[899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00
[899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
[899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8
[899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000
[899688.160002] tracing_read_pipe+0x336/0x3c0
[899688.160002] __vfs_read+0x26/0x140
[899688.160002] vfs_read+0x87/0x130
[899688.160002] SyS_read+0x42/0x90
[899688.160002] do_syscall_64+0x74/0x160
It caught the process in the middle of trace_access_unlock(). There is
no loop. So, it must be looping in the caller tracing_read_pipe()
via the "waitagain" label.
Crashdump analyze uncovered that iter->seq was completely zeroed
at this point, including iter->seq.seq.size. It means that
print_trace_line() was never able to print anything and
there was no forward progress.
The culprit seems to be in the code:
/* reset all but tr, trace, and overruns */
memset(&iter->seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
It was added by the commit 53d0aa773053ab182877 ("ftrace:
add logic to record overruns"). It was v2.6.27-rc1.
It was the time when iter->seq looked like:
struct trace_seq {
unsigned char buffer[PAGE_SIZE];
unsigned int len;
};
There was no "size" variable and zeroing was perfectly fine.
The solution is to reinitialize the structure after or without
zeroing.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.
Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu
Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer")
Cc: [email protected]
Signed-off-by: Srivatsa S. Bhat (VMware) <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.
Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu
Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector")
Cc: [email protected]
Signed-off-by: Srivatsa S. Bhat (VMware) <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
The removal of the longjmp code in recordmcount.c mistakenly made the return
of make_nop() being negative an exit of nop_mcount(). It should not exit the
routine, but instead just not process that part of the code. By exiting with
an error code, it would cause the update of recordmcount to fail some files
which would fail the build if ftrace function tracing was enabled.
Link: http://lkml.kernel.org/r/[email protected]
Reported-by: Uwe Kleine-König <[email protected]>
Tested-by: Uwe Kleine-König <[email protected]>
Fixes: 3f1df12019f3 ("recordmcount: Rewrite error/success handling")
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
If on boot up, lockdown is activated for tracefs, don't even bother creating
the files. This can also prevent instances from being created if lockdown is
in effect.
Link: http://lkml.kernel.org/r/CAHk-=whC6Ji=fWnjh2+eS4b15TnbsS4VPVtvBOwCy1jjEG_JHQ@mail.gmail.com
Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
Added various checks on open tracefs calls to see if tracefs is in lockdown
mode, and if so, to return -EPERM.
Note, the event format files (which are basically standard on all machines)
as well as the enabled_functions file (which shows what is currently being
traced) are not lockde down. Perhaps they should be, but it seems counter
intuitive to lockdown information to help you know if the system has been
modified.
Link: http://lkml.kernel.org/r/CAHk-=wj7fGPKUspr579Cii-w_y60PtRaiDgKuxVtBAMK0VNNkA@mail.gmail.com
Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
Currently, most files in the tracefs directory test if tracing_disabled is
set. If so, it should return -ENODEV. The tracing_disabled is called when
tracing is found to be broken. Originally it was done in case the ring
buffer was found to be corrupted, and we wanted to prevent reading it from
crashing the kernel. But it's also called if a tracing selftest fails on
boot. It's a one way switch. That is, once it is triggered, tracing is
disabled until reboot.
As most tracefs files can also be used by instances in the tracefs
directory, they need to be carefully done. Each instance has a trace_array
associated to it, and when the instance is removed, the trace_array is
freed. But if an instance is opened with a reference to the trace_array,
then it requires looking up the trace_array to get its ref counter (as there
could be a race with it being deleted and the open itself). Once it is
found, a reference is added to prevent the instance from being removed (and
the trace_array associated with it freed).
Combine the two checks (tracing_disabled and trace_array_get()) into a
single helper function. This will also make it easier to add lockdown to
tracefs later.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
Instead of having the trace events system open call open code the taking of
the trace_array descriptor (with trace_array_get()) and then calling
trace_open_generic(), have it use the tracing_open_generic_tr() that does
the combination of the two. This requires making tracing_open_generic_tr()
global.
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|
|
As instances may have different tracers available, we need to look at the
trace_array descriptor that shows the list of the available tracers for the
instance. But there's a race between opening the file and an admin
deleting the instance. The trace_array_get() needs to be called before
accessing the trace_array.
Cc: [email protected]
Fixes: 607e2ea167e56 ("tracing: Set up infrastructure to allow tracers for instances")
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
|