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Filename Latest commit message Latest commit date
Stanislav Fomichev 54e9c9d4b5 bpf: remove __rcu annotations from bpf_prog_array
Drop __rcu annotations and rcu read sections from bpf_prog_array
helper functions. They are not needed since all existing callers
call those helpers from the rcu update side while holding a mutex.
This guarantees that use-after-free could not happen.

In the next patches I'll fix the callers with missing
rcu_dereference_protected to make sparse/lockdep happy, the proper
way to use these helpers is:

	struct bpf_prog_array __rcu *progs = ...;
	struct bpf_prog_array *p;

	mutex_lock(&mtx);
	p = rcu_dereference_protected(progs, lockdep_is_held(&mtx));
	bpf_prog_array_length(p);
	bpf_prog_array_copy_to_user(p, ...);
	bpf_prog_array_delete_safe(p, ...);
	bpf_prog_array_copy_info(p, ...);
	bpf_prog_array_copy(p, ...);
	bpf_prog_array_free(p);
	mutex_unlock(&mtx);

No functional changes! rcu_dereference_protected with lockdep_is_held
should catch any cases where we update prog array without a mutex
(I've looked at existing call sites and I think we hold a mutex
everywhere).

Motivation is to fix sparse warnings:
kernel/bpf/core.c:1803:9: warning: incorrect type in argument 1 (different address spaces)
kernel/bpf/core.c:1803:9:    expected struct callback_head *head
kernel/bpf/core.c:1803:9:    got struct callback_head [noderef] <asn:4> *
kernel/bpf/core.c:1877:44: warning: incorrect type in initializer (different address spaces)
kernel/bpf/core.c:1877:44:    expected struct bpf_prog_array_item *item
kernel/bpf/core.c:1877:44:    got struct bpf_prog_array_item [noderef] <asn:4> *
kernel/bpf/core.c:1901:26: warning: incorrect type in assignment (different address spaces)
kernel/bpf/core.c:1901:26:    expected struct bpf_prog_array_item *existing
kernel/bpf/core.c:1901:26:    got struct bpf_prog_array_item [noderef] <asn:4> *
kernel/bpf/core.c:1935:26: warning: incorrect type in assignment (different address spaces)
kernel/bpf/core.c:1935:26:    expected struct bpf_prog_array_item *[assigned] existing
kernel/bpf/core.c:1935:26:    got struct bpf_prog_array_item [noderef] <asn:4> *

v2:
* remove comment about potential race; that can't happen
  because all callers are in rcu-update section

Cc: Roman Gushchin <guro@fb.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-29 15:17:35 +02:00
arch riscv: bpf: eliminate zero extension code-gen 2019-05-24 18:58:38 -07:00
block for-5.2/block-post-20190516 2019-05-16 19:08:15 -07:00
certs
crypto SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
Documentation dt-bindings: phy: dp83867: Add documentation for disabling clock output 2019-05-22 17:40:17 -07:00
drivers nfp: bpf: eliminate zero extension code-gen 2019-05-24 18:58:38 -07:00
fs Fix a gfs2 sign extension bug introduced in v4.3. 2019-05-22 08:31:09 -07:00
include bpf: remove __rcu annotations from bpf_prog_array 2019-05-29 15:17:35 +02:00
init treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel bpf: remove __rcu annotations from bpf_prog_array 2019-05-29 15:17:35 +02:00
lib SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
net hv_sock: perf: loop in send() to maximize bandwidth 2019-05-22 18:00:36 -07:00
samples selftests/bpf: convert test_cgrp2_attach2 example into kselftest 2019-05-28 09:30:02 -07:00
scripts SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
security selinux/stable-5.2 PR 20190521 2019-05-21 12:51:20 -07:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
tools selftests/bpf: fix compilation error for flow_dissector.c 2019-05-29 15:15:07 +02:00
usr
virt treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-20 08:21:07 -07:00
Makefile Linux 5.2-rc1 2019-05-19 15:47:09 -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.