linux-stable.git/include/linux/bpf.h, branch v5.11.8

bpf: Declare __bpf_free_used_maps() unconditionally

2021-03-04T11:13:59+00:00

[ Upstream commit 936f8946bdb48239f4292812d4d2e26c6d328c95 ]

__bpf_free_used_maps() is always defined in kernel/bpf/core.c, while
include/linux/bpf.h is guarding it behind CONFIG_BPF_SYSCALL. Move it out of
that guard region and fix compiler warning.

Fixes: a2ea07465c8d ("bpf: Fix missing prog untrack in release_maps")
Reported-by: kernel test robot 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20210112075520.4103414-4-andrii@kernel.org
Signed-off-by: Sasha Levin

bpf: Add bpf_patch_call_args prototype to include/linux/bpf.h

2021-03-04T11:13:40+00:00

[ Upstream commit a643bff752dcf72a07e1b2ab2f8587e4f51118be ]

Add bpf_patch_call_args() prototype. This function is called from BPF verifier
and only if CONFIG_BPF_JIT_ALWAYS_ON is not defined. This fixes compiler
warning about missing prototype in some kernel configurations.

Fixes: 1ea47e01ad6e ("bpf: add support for bpf_call to interpreter")
Reported-by: kernel test robot 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20210112075520.4103414-2-andrii@kernel.org
Signed-off-by: Sasha Levin

bpf: Only provide bpf_sock_from_file with CONFIG_NET

2020-12-09T02:23:36+00:00

This moves the bpf_sock_from_file definition into net/core/filter.c
which only gets compiled with CONFIG_NET and also moves the helper proto
usage next to other tracing helpers that are conditional on CONFIG_NET.

This avoids
  ld: kernel/trace/bpf_trace.o: in function `bpf_sock_from_file':
  bpf_trace.c:(.text+0xe23): undefined reference to `sock_from_file'
When compiling a kernel with BPF and without NET.

Reported-by: kernel test robot 
Reported-by: Randy Dunlap 
Signed-off-by: Florent Revest 
Signed-off-by: Alexei Starovoitov 
Acked-by: Randy Dunlap 
Acked-by: Martin KaFai Lau 
Acked-by: KP Singh 
Link: https://lore.kernel.org/bpf/20201208173623.1136863-1-revest@chromium.org

bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier

2020-12-04T01:38:21+00:00

Remove a permeating assumption thoughout BPF verifier of vmlinux BTF. Instead,
wherever BTF type IDs are involved, also track the instance of struct btf that
goes along with the type ID. This allows to gradually add support for kernel
module BTFs and using/tracking module types across BPF helper calls and
registers.

This patch also renames btf_id() function to btf_obj_id() to minimize naming
clash with using btf_id to denote BTF *type* ID, rather than BTF *object*'s ID.

Also, altough btf_vmlinux can't get destructed and thus doesn't need
refcounting, module BTFs need that, so apply BTF refcounting universally when
BPF program is using BTF-powered attachment (tp_btf, fentry/fexit, etc). This
makes for simpler clean up code.

Now that BTF type ID is not enough to uniquely identify a BTF type, extend BPF
trampoline key to include BTF object ID. To differentiate that from target
program BPF ID, set 31st bit of type ID. BTF type IDs (at least currently) are
not allowed to take full 32 bits, so there is no danger of confusing that bit
with a valid BTF type ID.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20201203204634.1325171-10-andrii@kernel.org

bpf: Eliminate rlimit-based memory accounting for bpf progs

2020-12-03T02:32:47+00:00

Do not use rlimit-based memory accounting for bpf progs. It has been
replaced with memcg-based memory accounting.

Signed-off-by: Roman Gushchin 
Signed-off-by: Alexei Starovoitov 
Acked-by: Song Liu 
Link: https://lore.kernel.org/bpf/20201201215900.3569844-34-guro@fb.com

bpf: Eliminate rlimit-based memory accounting infra for bpf maps

2020-12-03T02:32:47+00:00

Remove rlimit-based accounting infrastructure code, which is not used
anymore.

To provide a backward compatibility, use an approximation of the
bpf map memory footprint as a "memlock" value, available to a user
via map info. The approximation is based on the maximal number of
elements and key and value sizes.

Signed-off-by: Roman Gushchin 
Signed-off-by: Alexei Starovoitov 
Acked-by: Song Liu 
Link: https://lore.kernel.org/bpf/20201201215900.3569844-33-guro@fb.com

bpf: Prepare for memcg-based memory accounting for bpf maps

2020-12-03T02:32:34+00:00

Bpf maps can be updated from an interrupt context and in such
case there is no process which can be charged. It makes the memory
accounting of bpf maps non-trivial.

Fortunately, after commit 4127c6504f25 ("mm: kmem: enable kernel
memcg accounting from interrupt contexts") and commit b87d8cefe43c
("mm, memcg: rework remote charging API to support nesting")
it's finally possible.

To make the ownership model simple and consistent, when the map
is created, the memory cgroup of the current process is recorded.
All subsequent allocations related to the bpf map are charged to
the same memory cgroup. It includes allocations made by any processes
(even if they do belong to a different cgroup) and from interrupts.

This commit introduces 3 new helpers, which will be used by following
commits to enable the accounting of bpf maps memory:
  - bpf_map_kmalloc_node()
  - bpf_map_kzalloc()
  - bpf_map_alloc_percpu()

They are wrapping popular memory allocation functions. They set
the active memory cgroup to the map's memory cgroup and add
__GFP_ACCOUNT to the passed gfp flags. Then they call into
the corresponding memory allocation function and restore
the original active memory cgroup.

These helpers are supposed to use everywhere except the map creation
path. During the map creation when the map structure is allocated by
itself, it cannot be passed to those helpers. In those cases default
memory allocation function will be used with the __GFP_ACCOUNT flag.

Signed-off-by: Roman Gushchin 
Acked-by: Daniel Borkmann 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20201201215900.3569844-7-guro@fb.com

bpf: Add bpf_ktime_get_coarse_ns helper

2020-11-18T22:25:32+00:00

The helper uses CLOCK_MONOTONIC_COARSE source of time that is less
accurate but more performant.

We have a BPF CGROUP_SKB firewall that supports event logging through
bpf_perf_event_output(). Each event has a timestamp and currently we use
bpf_ktime_get_ns() for it. Use of bpf_ktime_get_coarse_ns() saves ~15-20
ns in time required for event logging.

bpf_ktime_get_ns():
EgressLogByRemoteEndpoint                              113.82ns    8.79M

bpf_ktime_get_coarse_ns():
EgressLogByRemoteEndpoint                               95.40ns   10.48M

Signed-off-by: Dmitrii Banshchikov 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20201117184549.257280-1-me@ubique.spb.ru

bpf: Load and verify kernel module BTFs

2020-11-10T23:25:53+00:00

Add kernel module listener that will load/validate and unload module BTF.
Module BTFs gets ID generated for them, which makes it possible to iterate
them with existing BTF iteration API. They are given their respective module's
names, which will get reported through GET_OBJ_INFO API. They are also marked
as in-kernel BTFs for tooling to distinguish them from user-provided BTFs.

Also, similarly to vmlinux BTF, kernel module BTFs are exposed through
sysfs as /sys/kernel/btf/. This is convenient for user-space
tools to inspect module BTF contents and dump their types with existing tools:

[vmuser@archvm bpf]$ ls -la /sys/kernel/btf
total 0
drwxr-xr-x  2 root root       0 Nov  4 19:46 .
drwxr-xr-x 13 root root       0 Nov  4 19:46 ..

...

-r--r--r--  1 root root     888 Nov  4 19:46 irqbypass
-r--r--r--  1 root root  100225 Nov  4 19:46 kvm
-r--r--r--  1 root root   35401 Nov  4 19:46 kvm_intel
-r--r--r--  1 root root     120 Nov  4 19:46 pcspkr
-r--r--r--  1 root root     399 Nov  4 19:46 serio_raw
-r--r--r--  1 root root 4094095 Nov  4 19:46 vmlinux

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/bpf/20201110011932.3201430-5-andrii@kernel.org

bpf: Implement get_current_task_btf and RET_PTR_TO_BTF_ID

2020-11-06T16:08:37+00:00

The currently available bpf_get_current_task returns an unsigned integer
which can be used along with BPF_CORE_READ to read data from
the task_struct but still cannot be used as an input argument to a
helper that accepts an ARG_PTR_TO_BTF_ID of type task_struct.

In order to implement this helper a new return type, RET_PTR_TO_BTF_ID,
is added. This is similar to RET_PTR_TO_BTF_ID_OR_NULL but does not
require checking the nullness of returned pointer.

Signed-off-by: KP Singh 
Signed-off-by: Alexei Starovoitov 
Acked-by: Song Liu 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20201106103747.2780972-6-kpsingh@chromium.org