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Dave Marchevsky ca34ce29fc bpf: Improve docstring for BPF_F_USER_BUILD_ID flag
Most tools which use bpf_get_stack or bpf_get_stackid symbolicate the
stack - meaning the stack of addresses in the target process' address
space is transformed into meaningful symbol names. The
BPF_F_USER_BUILD_ID flag eases this process by finding the build_id of
the file-backed vma which the address falls in and translating the
address to an offset within the backing file.

To be more specific, the offset is a "file offset" from the beginning of
the backing file. The symbols in ET_DYN ELF objects have a st_value
which is also described as an "offset" - but an offset in the process
address space, relative to the base address of the object.

It's necessary to translate between the "file offset" and "virtual
address offset" during symbolication before they can be directly
compared. Failure to do so can lead to confusing bugs, so this patch
clarifies language in the documentation in an attempt to keep this from
happening.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220808164723.3107500-1-davemarchevsky@fb.com
2022-08-08 15:15:05 -07:00
arch Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
block iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto This update includes the following changes: 2022-08-02 17:45:14 -07:00
Documentation Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
drivers Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
fs zonefs changes for 5.20-rc1 2022-08-03 15:21:53 -07:00
include bpf: Improve docstring for BPF_F_USER_BUILD_ID flag 2022-08-08 15:15:05 -07:00
init Several core optimizations: 2022-08-03 09:45:08 -07:00
io_uring iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel bpf: Verifier cleanups 2022-08-08 17:54:06 +02:00
lib Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm for-5.20-tag 2022-08-03 14:54:52 -07:00
net Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
samples Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-07-22 16:55:44 -07:00
scripts Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
security linux-kselftest-kunit-5.20-rc1 2022-08-02 19:34:45 -07:00
sound ASoC: Drop Rockchip BCLK management for v5.19 2022-07-15 12:31:07 +02:00
tools bpf: Improve docstring for BPF_F_USER_BUILD_ID flag 2022-08-08 15:15:05 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking changes for 6.0. 2022-08-03 16:29:08 -07:00
Makefile linux-kselftest-next-5.20-rc1 2022-08-02 19:44:56 -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.