Enabling of large number of functions by echoing in a large subset of the
functions in available_filter_functions can take a very long time. The
process requires testing all functions registered by the function tracer
(which is in the 10s of thousands), and doing a kallsyms lookup to convert
the ip address into a name, then comparing that name with the string passed
in.
When a function causes the function tracer to crash the system, a binary
bisect of the available_filter_functions can be done to find the culprit.
But this requires passing in half of the functions in
available_filter_functions over and over again, which makes it basically a
O(n^2) operation. With 40,000 functions, that ends up bing 1,600,000,000
opertions! And enabling this can take over 20 minutes.
As a quick speed up, if a number is passed into one of the filter files,
instead of doing a search, it just enables the function at the corresponding
line of the available_filter_functions file. That is:
# echo 50 > set_ftrace_filter
# cat set_ftrace_filter
x86_pmu_commit_txn
# head -50 available_filter_functions | tail -1
x86_pmu_commit_txn
This allows setting of half the available_filter_functions to take place in
less than a second!
# time seq 20000 > set_ftrace_filter
real 0m0.042s
user 0m0.005s
sys 0m0.015s
# wc -l set_ftrace_filter
20000 set_ftrace_filter
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As the predicat_parse() code is rather complex, commenting subtleties is
important. The switch case statement should be commented to describe that it
is only looking for two '&' or '|' together, which is why the fall through
to an error is after the check.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
There is a plan to build the kernel with -Wimplicit-fallthrough and
this place in the code produced a warning (W=1).
This commit remove the following warning:
kernel/trace/trace_events_filter.c:494:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
Link: http://lkml.kernel.org/r/20190114203039.16535-2-malat@debian.org
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
There is a plan to build the kernel with -Wimplicit-fallthrough and
this place in the code produced a warning (W=1).
This commit remove the following warning:
kernel/trace/trace_probe.c:302:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
Link: http://lkml.kernel.org/r/20190114203039.16535-1-malat@debian.org
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull x86 fixes from Thomas Gleixner:
"A few updates for x86:
- Fix an unintended sign extension issue in the fault handling code
- Rename the new resource control config switch so it's less
confusing
- Avoid setting up EFI info in kexec when the EFI runtime is
disabled.
- Fix the microcode version check in the AMD microcode loader so it
only loads higher version numbers and never downgrades
- Set EFER.LME in the 32bit trampoline before returning to long mode
to handle older AMD/KVM behaviour properly.
- Add Darren and Andy as x86/platform reviewers"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Avoid confusion over the new X86_RESCTRL config
x86/kexec: Don't setup EFI info if EFI runtime is not enabled
x86/microcode/amd: Don't falsely trick the late loading mechanism
MAINTAINERS: Add Andy and Darren as arch/x86/platform/ reviewers
x86/fault: Fix sign-extend unintended sign extension
x86/boot/compressed/64: Set EFER.LME=1 in 32-bit trampoline before returning to long mode
x86/cpu: Add Atom Tremont (Jacobsville)
Pull cpu hotplug fixes from Thomas Gleixner:
"Two fixes for the cpu hotplug machinery:
- Replace the overly clever 'SMT disabled by BIOS' detection logic as
it breaks KVM scenarios and prevents speculation control updates
when the Hyperthreads are brought online late after boot.
- Remove a redundant invocation of the speculation control update
function"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
x86/speculation: Remove redundant arch_smt_update() invocation
Pull perf fixes from Thomas Gleixner:
"A pile of perf updates:
- Fix broken sanity check in the /proc/sys/kernel/perf_cpu_time_max_percent
write handler
- Cure a perf script crash which caused by an unitinialized data
structure
- Highlight the hottest instruction in perf top and not a random one
- Cure yet another clang issue when building perf python
- Handle topology entries with no CPU correctly in the tools
- Handle perf data which contains both tracepoints and performance
counter entries correctly.
- Add a missing NULL pointer check in perf ordered_events_free()"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf script: Fix crash when processing recorded stat data
perf top: Fix wrong hottest instruction highlighted
perf tools: Handle TOPOLOGY headers with no CPU
perf python: Remove -fstack-clash-protection when building with some clang versions
perf core: Fix perf_proc_update_handler() bug
perf script: Fix crash with printing mixed trace point and other events
perf ordered_events: Fix crash in ordered_events__free
Pull EFI fix from Thomas Gleixner:
"The dump info for the efi page table debugging lacks a terminator
which causes the kernel to crash when the debugfile is read"
* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/arm64: Fix debugfs crash by adding a terminator for ptdump marker
Pull btrfs fixes from David Sterba:
- regression fix: transaction commit can run away due to delayed ref
waiting heuristic, this is not necessary now because of the proper
reservation mechanism introduced in 5.0
- regression fix: potential crash due to use-before-check of an ERR_PTR
return value
- fix for transaction abort during transaction commit that needs to
properly clean up pending block groups
- fix deadlock during b-tree node/leaf splitting, when this happens on
some of the fundamental trees, we must prevent new tree block
allocation to re-enter indirectly via the block group flushing path
- potential memory leak after errors during mount
* tag 'for-5.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: On error always free subvol_name in btrfs_mount
btrfs: clean up pending block groups when transaction commit aborts
btrfs: fix potential oops in device_list_add
btrfs: don't end the transaction for delayed refs in throttle
Btrfs: fix deadlock when allocating tree block during leaf/node split
Pull Devicetree fix from Rob Herring:
"A single fix for building DT bindings in-tree"
* tag 'devicetree-fixes-for-5.0-3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
dt-bindings: Fix dt_binding_check target for in tree builds
Pull RISC-V fixes from Palmer Dabbelt:
"This contains a handful of mostly-independent patches:
- make our port respect TIF_NEED_RESCHED, which fixes
CONFIG_PREEMPT=y kernels
- fix double-put of OF nodes
- fix a misspelling of target in our Kconfig
- generic PCIe is enabled in our defconfig
- fix our SBI early console to properly handle line
endings
- fix max_low_pfn being counted in PFNs
- a change to TASK_UNMAPPED_BASE to match what other
arches do
This has passed my standard 'boot Fedora' flow"
* tag 'riscv-for-linus-5.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
riscv: Adjust mmap base address at a third of task size
riscv: fixup max_low_pfn with PFN_DOWN.
tty/serial: use uart_console_write in the RISC-V SBL early console
RISC-V: defconfig: Add CRYPTO_DEV_VIRTIO=y
RISC-V: defconfig: Enable Generic PCIE by default
RISC-V: defconfig: Move CONFIG_PCI{,E_XILINX}
RISC-V: Kconfig: fix spelling mistake "traget" -> "target"
RISC-V: asm/page.h: fix spelling mistake "CONFIG_64BITS" -> "CONFIG_64BIT"
RISC-V: fix bad use of of_node_put
RISC-V: Add _TIF_NEED_RESCHED check for kernel thread when CONFIG_PREEMPT=y
Pull block fixes from Jens Axboe:
"A few fixes that should go into this release. This contains:
- MD pull request from Song, fixing a recovery OOM issue (Alexei)
- Fix for a sync related stall (Jianchao)
- Dummy callback for timeouts (Tetsuo)
- IDE atapi sense ordering fix (me)"
* tag 'for-linus-20190202' of git://git.kernel.dk/linux-block:
ide: ensure atapi sense request aren't preempted
blk-mq: fix a hung issue when fsync
block: pass no-op callback to INIT_WORK().
md/raid5: fix 'out of memory' during raid cache recovery
Pull SCSI fixes from James Bottomley:
"Five minor bug fixes.
The libfc one is a tiny memory leak, the zfcp one is an incorrect user
visible parameter and the rest are on error legs or obscure features"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: 53c700: pass correct "dev" to dma_alloc_attrs()
scsi: bnx2fc: Fix error handling in probe()
scsi: scsi_debug: fix write_same with virtual_gb problem
scsi: libfc: free skb when receiving invalid flogi resp
scsi: zfcp: fix sysfs block queue limit output for max_segment_size
Merge misc fixes from Andrew Morton:
"24 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (24 commits)
autofs: fix error return in autofs_fill_super()
autofs: drop dentry reference only when it is never used
fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()
mm: migrate: don't rely on __PageMovable() of newpage after unlocking it
psi: clarify the Kconfig text for the default-disable option
mm, memory_hotplug: __offline_pages fix wrong locking
mm: hwpoison: use do_send_sig_info() instead of force_sig()
kasan: mark file common so ftrace doesn't trace it
init/Kconfig: fix grammar by moving a closing parenthesis
lib/test_kmod.c: potential double free in error handling
mm, oom: fix use-after-free in oom_kill_process
mm/hotplug: invalid PFNs from pfn_to_online_page()
mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages
psi: fix aggregation idle shut-off
mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone
mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone
oom, oom_reaper: do not enqueue same task twice
mm: migrate: make buffer_migrate_page_norefs() actually succeed
kernel/exit.c: release ptraced tasks before zap_pid_ns_processes
x86_64: increase stack size for KASAN_EXTRA
...
Pull xtensa fixes from Max Filippov:
- fix ccount_timer_shutdown for secondary CPUs
- fix secondary CPU initialization
- fix secondary CPU reset vector clash with double exception vector
- fix present CPUs when booting with 'maxcpus' parameter
- limit possible CPUs by configured NR_CPUS
- issue a warning if xtensa PIC is asked to retrigger anything other
than software IRQ
- fix masking/unmasking of the first two IRQs on xtensa MX PIC
- fix typo in Kconfig description for user space unaligned access
feature
- fix Kconfig warning for selecting BUILTIN_DTB
* tag 'xtensa-20190201' of git://github.com/jcmvbkbc/linux-xtensa:
xtensa: SMP: limit number of possible CPUs by NR_CPUS
xtensa: rename BUILTIN_DTB to BUILTIN_DTB_SOURCE
xtensa: Fix typo use space=>user space
drivers/irqchip: xtensa-mx: fix mask and unmask
drivers/irqchip: xtensa: add warning to irq_retrigger
xtensa: SMP: mark each possible CPU as present
xtensa: smp_lx200_defconfig: fix vectors clash
xtensa: SMP: fix secondary CPU initialization
xtensa: SMP: fix ccount_timer_shutdown
