Before this patch, a simple 'perf record' could fail if kptr_restrict is
set to 1 (for normal user) or 2 (for root):
# perf record ls
WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted,
check /proc/sys/kernel/kptr_restrict.
Samples in kernel functions may not be resolved if a suitable vmlinux
file is not found in the buildid cache or in the vmlinux path.
Samples in kernel modules won't be resolved at all.
If some relocation was applied (e.g. kexec) symbols may be misresolved
even with a suitable vmlinux or kallsyms file.
Segmentation fault (core dumped)
This patch skips perf_event__synthesize_kernel_mmap() when kptr is not
available.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fixes: 45e9005690 ("perf machine: Do not bail out if not managing to read ref reloc symbol")
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464081688-167940-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvements from Arnaldo Carvalho de Melo:
User visible changes:
- Add "srcline_from" and "srcline_to" branch sort keys to 'perf top' and
'perf report' (Andi Kleen)
Infrastructure changes:
- Make 'perf trace' auto-attach fd->name and ptr->name beautifiers based
on the name of syscall arguments, this way new syscalls that have
'const char * (path,pathname,filename)' will use the fd->name beautifier
(vfs_getname perf probe, if in place) and the 'fd->name' (vfs_getname
or via /proc/PID/fd/) (Arnaldo Carvalho de Melo)
- Infrastructure to read from a ring buffer in backward write mode (Wang Nan)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
record__mmap_read() writes data from ring buffer into perf.data. 'head'
is maintained by the kernel, points to the last written record.
'old' is maintained by perf, points to the record read in previous
round. record__mmap_read() saves data from 'old' to 'head' to
perf.data.
The names of these variables are not very intutive. In addition,
when dealing with backward writing ring buffer, the md->prev pointer
should point to 'head' instead of the last byte it got.
Add 'start' and 'end' pointer to make code clear and set md->prev to
'head' instead of the moved 'old' pointer. This patch doesn't change
behavior since:
buf = &data[old & md->mask];
size = head - old;
old += size; <--- Here, old == head
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1463987628-163563-4-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
User visible changes:
- We should not use the current value of the kernel.perf_event_max_stack as the
default value for --max-stack in tools that can process perf.data files, they
will only match if that sysctl wasn't changed from its default value at the
time the perf.data file was recorded, fix it.
This fixes a bug where a 'perf record -a --call-graph dwarf ; perf report'
produces a glibc invalid free backtrace (Arnaldo Carvalho de Melo)
- Provide a better warning when running 'perf trace' on a system where the
kernel.kptr_restrict is set to 1, similar to the one produced by 'perf record',
noticed on ubuntu 16.04 where this is the default kptr_restrict setting.
(Arnaldo Carvalho de Melo)
- Fix ordering of instructions in the annotation code, noticed when annotating
ARM binaries, now that table is auto-ordered at first use, to avoid more such
problems (Chris Ryder)
- Set buildid dir under symfs when --symfs is provided (He Kuang)
- Fix the 'exit_group()' syscall output in 'perf trace' (Arnaldo Carvalho de Melo)
- Only auto set call-graph to "dwarf" in 'perf trace' when syscalls are being
traced (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This means the user can't access /proc/kallsyms, for instance, because
/proc/sys/kernel/kptr_restrict is set to 1.
Instead leave the ref_reloc_sym as NULL and code using it will cope.
This allows 'perf trace' to work on such systems for !root, the only
issue would be when trying to resolve kernel symbols, which happens,
for instance, in some libtracevent plugins. A warning for that case
will be provided in the next patch in this series.
Noticed in Ubuntu 16.04, that comes with kptr_restrict=1.
Reported-by: Milian Wolff <milian.wolff@kdab.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-knpu3z4iyp2dxpdfm798fac4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
User visible changes:
- Honour the kernel.perf_event_max_stack knob more precisely by not counting
PERF_CONTEXT_{KERNEL,USER} when deciding when to stop adding entries to
the perf_sample->ip_callchain[] array (Arnaldo Carvalho de Melo)
- Fix identation of 'stalled-backend-cycles' in 'perf stat' (Namhyung Kim)
- Update runtime using 'cpu-clock' event in 'perf stat' (Namhyung Kim)
- Use 'cpu-clock' for cpu targets in 'perf stat' (Namhyung Kim)
- Avoid fractional digits for integer scales in 'perf stat' (Andi Kleen)
- Store vdso buildid unconditionally, as it appears in callchains and
we're not checking those when creating the build-id table, so we
end up not being able to resolve VDSO symbols when doing analysis
on a different machine than the one where recording was done, possibly
of a different arch even (arm -> x86_64) (He Kuang)
Infrastructure changes:
- Generalize max_stack sysctl handler, will be used for configuring
multiple kernel knobs related to callchains (Arnaldo Carvalho de Melo)
Cleanups:
- Introduce DSO__NAME_KALLSYMS and DSO__NAME_KCORE, to stop using
open coded strings (Masami Hiramatsu)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When booting with nr_cpus=1, uncore_pci_probe tries to init the PCI/uncore
also for the other packages and fails with warning when they are not found.
The warning is bogus because it's correct to fail here for packages which are
not initialized. Remove it and return silently.
Fixes: cf6d445f68 "perf/x86/uncore: Track packages, not per CPU data"
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We will use it to count how many addresses are in the entry->ip[] array,
excluding PERF_CONTEXT_{KERNEL,USER,etc} entries, so that we can really
return the number of entries specified by the user via the relevant
sysctl, kernel.perf_event_max_contexts, or via the per event
perf_event_attr.sample_max_stack knob.
This way we keep the perf_sample->ip_callchain->nr meaning, that is the
number of entries, be it real addresses or PERF_CONTEXT_ entries, while
honouring the max_stack knobs, i.e. the end result will be max_stack
entries if we have at least that many entries in a given stack trace.
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-s8teto51tdqvlfhefndtat9r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently only the task-clock event updates the runtime_nsec so it
cannot show the metric when using cpu-clock events. However cpu clock
works basically same as task-clock, so no need to not update the runtime
IMHO.
Before:
# perf stat -a -e cpu-clock,context-switches,page-faults,cycles sleep 0.1
Performance counter stats for 'system wide':
1217.759506 cpu-clock (msec)
93 context-switches
61 page-faults
18,958,022 cycles
0.101393794 seconds time elapsed
After:
Performance counter stats for 'system wide':
1220.471884 cpu-clock (msec) # 12.013 CPUs utilized
118 context-switches # 0.097 K/sec
59 page-faults # 0.048 K/sec
17,941,247 cycles # 0.015 GHz
0.101594777 seconds time elapsed
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1463119263-5569-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull x86 platform updates from Ingo Molnar:
"The main change is the addition of SGI/UV4 support"
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
x86/platform/UV: Fix incorrect nodes and pnodes for cpuless and memoryless nodes
x86/platform/UV: Remove Obsolete GRU MMR address translation
x86/platform/UV: Update physical address conversions for UV4
x86/platform/UV: Build GAM reference tables
x86/platform/UV: Support UV4 socket address changes
x86/platform/UV: Add obtaining GAM Range Table from UV BIOS
x86/platform/UV: Add UV4 addressing discovery function
x86/platform/UV: Fold blade info into per node hub info structs
x86/platform/UV: Allocate common per node hub info structs on local node
x86/platform/UV: Move blade local processor ID to the per cpu info struct
x86/platform/UV: Move scir info to the per cpu info struct
x86/platform/UV: Create per cpu info structs to replace per hub info structs
x86/platform/UV: Update MMIOH setup function to work for both UV3 and UV4
x86/platform/UV: Clean up redunduncies after merge of UV4 MMR definitions
x86/platform/UV: Add UV4 Specific MMR definitions
x86/platform/UV: Prep for UV4 MMR updates
x86/platform/UV: Add UV MMR Illegal Access Function
x86/platform/UV: Add UV4 Specific Defines
x86/platform/UV: Add UV Architecture Defines
x86/platform/UV: Add Initial UV4 definitions
...
Pull x86 debug cleanup from Ingo Molnar:
"A printk() output simplification"
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/dumpstack: Combine some printk()s
Pull x86 boot updates from Ingo Molnar:
"The biggest changes in this cycle were:
- prepare for more KASLR related changes, by restructuring, cleaning
up and fixing the existing boot code. (Kees Cook, Baoquan He,
Yinghai Lu)
- simplifly/concentrate subarch handling code, eliminate
paravirt_enabled() usage. (Luis R Rodriguez)"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
x86/KASLR: Clarify purpose of each get_random_long()
x86/KASLR: Add virtual address choosing function
x86/KASLR: Return earliest overlap when avoiding regions
x86/KASLR: Add 'struct slot_area' to manage random_addr slots
x86/boot: Add missing file header comments
x86/KASLR: Initialize mapping_info every time
x86/boot: Comment what finalize_identity_maps() does
x86/KASLR: Build identity mappings on demand
x86/boot: Split out kernel_ident_mapping_init()
x86/boot: Clean up indenting for asm/boot.h
x86/KASLR: Improve comments around the mem_avoid[] logic
x86/boot: Simplify pointer casting in choose_random_location()
x86/KASLR: Consolidate mem_avoid[] entries
x86/boot: Clean up pointer casting
x86/boot: Warn on future overlapping memcpy() use
x86/boot: Extract error reporting functions
x86/boot: Correctly bounds-check relocations
x86/KASLR: Clean up unused code from old 'run_size' and rename it to 'kernel_total_size'
x86/boot: Fix "run_size" calculation
x86/boot: Calculate decompression size during boot not build
...
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- MSR access API fixes and enhancements (Andy Lutomirski)
- early exception handling improvements (Andy Lutomirski)
- user-space FS/GS prctl usage fixes and improvements (Andy
Lutomirski)
- Remove the cpu_has_*() APIs and replace them with equivalents
(Borislav Petkov)
- task switch micro-optimization (Brian Gerst)
- 32-bit entry code simplification (Denys Vlasenko)
- enhance PAT handling in enumated CPUs (Toshi Kani)
... and lots of other cleanups/fixlets"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS
x86/entry/32: Remove asmlinkage_protect()
x86/entry/32: Remove GET_THREAD_INFO() from entry code
x86/entry, sched/x86: Don't save/restore EFLAGS on task switch
x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs
selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment
x86/tls: Synchronize segment registers in set_thread_area()
x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase
x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization
x86/segments/64: When load_gs_index fails, clear the base
x86/segments/64: When loadsegment(fs, ...) fails, clear the base
x86/asm: Make asm/alternative.h safe from assembly
x86/asm: Stop depending on ptrace.h in alternative.h
x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()
x86/asm: Make sure verify_cpu() has a good stack
x86/extable: Add a comment about early exception handlers
x86/msr: Set the return value to zero when native_rdmsr_safe() fails
x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y
x86/paravirt: Add paravirt_{read,write}_msr()
x86/msr: Carry on after a non-"safe" MSR access fails
...
