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Filename Latest commit message Latest commit date
Adrian Hunter 97860b483c perf thread-stack: Fix thread stack return from kernel for kernel-only case
Commit f08046cb30 ("perf thread-stack: Represent jmps to the start of a
different symbol") had the side-effect of introducing more stack entries
before return from kernel space.

When user space is also traced, those entries are popped before entry to
user space, but when user space is not traced, they get stuck at the
bottom of the stack, making the stack grow progressively larger.

Fix by detecting a return-from-kernel branch type, and popping kernel
addresses from the stack then.

Note, the problem and fix affect the exported Call Graph / Tree but not
the callindent option used by "perf script --call-trace".

Example:

  perf-with-kcore record example -e intel_pt//k -- ls
  perf-with-kcore script example --itrace=bep -s ~/libexec/perf-core/scripts/python/export-to-sqlite.py example.db branches calls
  ~/libexec/perf-core/scripts/python/exported-sql-viewer.py example.db

  Menu option: Reports -> Context-Sensitive Call Graph

  Before: (showing Call Path column only)

    Call Path
    ▶ perf
    ▼ ls
      ▼ 12111:12111
        ▶ setup_new_exec
        ▶ __task_pid_nr_ns
        ▶ perf_event_pid_type
        ▶ perf_event_comm_output
        ▶ perf_iterate_ctx
        ▶ perf_iterate_sb
        ▶ perf_event_comm
        ▶ __set_task_comm
        ▶ load_elf_binary
        ▶ search_binary_handler
        ▶ __do_execve_file.isra.41
        ▶ __x64_sys_execve
        ▶ do_syscall_64
        ▼ entry_SYSCALL_64_after_hwframe
          ▼ swapgs_restore_regs_and_return_to_usermode
            ▼ native_iret
              ▶ error_entry
              ▶ do_page_fault
              ▼ error_exit
                ▼ retint_user
                  ▶ prepare_exit_to_usermode
                  ▼ native_iret
                    ▶ error_entry
                    ▶ do_page_fault
                    ▼ error_exit
                      ▼ retint_user
                        ▶ prepare_exit_to_usermode
                        ▼ native_iret
                          ▶ error_entry
                          ▶ do_page_fault
                          ▼ error_exit
                            ▼ retint_user
                              ▶ prepare_exit_to_usermode
                              ▶ native_iret

  After: (showing Call Path column only)

    Call Path
    ▶ perf
    ▼ ls
      ▼ 12111:12111
        ▶ setup_new_exec
        ▶ __task_pid_nr_ns
        ▶ perf_event_pid_type
        ▶ perf_event_comm_output
        ▶ perf_iterate_ctx
        ▶ perf_iterate_sb
        ▶ perf_event_comm
        ▶ __set_task_comm
        ▶ load_elf_binary
        ▶ search_binary_handler
        ▶ __do_execve_file.isra.41
        ▶ __x64_sys_execve
        ▶ do_syscall_64
        ▶ entry_SYSCALL_64_after_hwframe
        ▶ page_fault
        ▼ entry_SYSCALL_64
          ▼ do_syscall_64
            ▶ __x64_sys_brk
            ▶ __x64_sys_access
            ▶ __x64_sys_openat
            ▶ __x64_sys_newfstat
            ▶ __x64_sys_mmap
            ▶ __x64_sys_close
            ▶ __x64_sys_read
            ▶ __x64_sys_mprotect
            ▶ __x64_sys_arch_prctl
            ▶ __x64_sys_munmap
            ▶ exit_to_usermode_loop
            ▶ __x64_sys_set_tid_address
            ▶ __x64_sys_set_robust_list
            ▶ __x64_sys_rt_sigaction
            ▶ __x64_sys_rt_sigprocmask
            ▶ __x64_sys_prlimit64
            ▶ __x64_sys_statfs
            ▶ __x64_sys_ioctl
            ▶ __x64_sys_getdents64
            ▶ __x64_sys_write
            ▶ __x64_sys_exit_group

Committer notes:

The first arg to the perf-with-kcore needs to be the same for the
'record' and 'script' lines, otherwise we'll record the perf.data file
and kcore_dir/ files in one directory ('example') to then try to use it
from the 'bep' directory, fix the instructions above it so that both use
'example'.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Fixes: f08046cb30 ("perf thread-stack: Represent jmps to the start of a different symbol")
Link: http://lkml.kernel.org/r/20190619064429.14940-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-06-25 08:47:10 -03:00
arch perf/x86/rapl: Get quirk state from new probe framework 2019-06-24 19:28:36 +02:00
block
certs
crypto
Documentation Merge branch 'x86/cpu' into perf/core, to pick up dependent patches 2019-06-24 19:26:39 +02:00
drivers Merge branch 'x86/cpu' into perf/core, to pick up dependent patches 2019-06-24 19:26:39 +02:00
fs Linux 5.2-rc6 2019-06-24 19:25:52 +02:00
include perf/cgroups: Don't rotate events for cgroups unnecessarily 2019-06-24 19:30:04 +02:00
init
ipc
kernel perf/cgroups: Don't rotate events for cgroups unnecessarily 2019-06-24 19:30:04 +02:00
lib SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
LICENSES
mm
net Bluetooth: Fix regression with minimum encryption key size alignment 2019-06-22 09:07:39 -07:00
samples SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
scripts treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
security SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
sound
tools perf thread-stack: Fix thread stack return from kernel for kernel-only case 2019-06-25 08:47:10 -03:00
usr
virt SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge branch 'x86/cpu' into perf/core, to pick up dependent patches 2019-06-24 19:26:39 +02:00
Makefile Linux 5.2-rc6 2019-06-22 16:01:36 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.