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Daniel Borkmann 68de5ef4c7 Merge branch 'bpf-stackmap-build-id'
Song Liu says:

====================
This work follows up discussion at Plumbers'17 on improving addr->sym
resolution of user stack traces. The following links have more information
of the discussion:

http://www.linuxplumbersconf.org/2017/ocw/proposals/4764
https://lwn.net/Articles/734453/     Section "Stack traces and kprobes"

Currently, bpf stackmap store address for each entry in the call trace.
To map these addresses to user space files, it is necessary to maintain
the mapping from these virtual address to symbols in the binary. Usually,
the user space profiler (such as perf) has to scan /proc/pid/maps at the
beginning of profiling, and monitor mmap2() calls afterwards. Given the
cost of maintaining the address map, this solution is not practical for
system wide profiling that is always on.

This patch tries to address this with a variation to stackmap. Instead
of storing addresses, the variation stores ELF file build_id + offset.
After profiling, a user space tool will look up these functions with
build_id (to find the binary or shared library) and the offset.

I also updated bcc/cc library for the stackmap (no python/lua support yet).
You can find the work at:

  https://github.com/liu-song-6/bcc/commits/bpf_get_stackid_v02

Changes v5 -> v6:

1. When kernel stack is added to stackmap with build_id, use fallback
   mechanism to store ip (status == BPF_STACK_BUILD_ID_IP).

Changes v4 -> v5:

1. Only allow build_id lookup in non-nmi context. Added comment and
   commit message to highlight this limitation.
2. Minor fix reported by kbuild test robot.

Changes v3 -> v4:

1. Add fallback when build_id lookup failed. In this case, status is set
   to BPF_STACK_BUILD_ID_IP, and ip of this entry is saved.
2. Handle cases where vma is only part of the file (vma->vm_pgoff != 0).
   Thanks to Teng for helping me identify this issue!
3. Address feedbacks for previous versions.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-03-15 01:14:16 +01:00
Documentation dt-bindings: net: dsa: marvell: describe compatibility string 2018-03-07 12:18:50 -05:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-03-06 01:20:46 -05:00
block for-linus-20180302 2018-03-02 09:35:36 -08:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto X.509: fix NULL dereference when restricting key with unsupported_sig 2018-02-22 14:38:34 +00:00
drivers cxgb3: remove VLA usage 2018-03-07 15:55:50 -05:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-03-06 01:20:46 -05:00
include bpf: extend stackmap to save binary_build_id+offset instead of address 2018-03-15 01:09:28 +01:00
init jump_label: Explicitly disable jump labels in __init code 2018-02-21 16:54:05 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel bpf: extend stackmap to save binary_build_id+offset instead of address 2018-03-15 01:09:28 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-03-06 01:20:46 -05:00
mm mm: don't defer struct page initialization for Xen pv guests 2018-02-21 15:35:43 -08:00
net ip6mr: remove synchronize_rcu() in favor of SOCK_RCU_FREE 2018-03-07 18:13:41 -05:00
samples samples/bpf: add example to test reading address 2018-03-08 02:22:34 +01:00
scripts Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
security net: Convert smack_net_ops 2018-02-27 11:01:39 -05:00
sound ALSA: x86: Fix potential crash at error path 2018-02-28 08:46:00 +01:00
tools bpf: add selftest for stackmap with BPF_F_STACK_BUILD_ID 2018-03-15 01:10:02 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: mmu: Fix overlap between public and private memslots 2018-02-24 01:43:36 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: ignore ASN.1 auto generated files 2018-02-14 21:05:38 +01:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS lan743x: Update MAINTAINERS to include lan743x driver 2018-03-07 11:44:42 -05:00
Makefile Linux 4.16-rc4 2018-03-04 14:54:11 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.