Commit Graph

44311 Commits

Author SHA1 Message Date
Benjamin Tissoires
8e83da9732 bpf: add bpf_wq_start
again, copy/paste from bpf_timer_start().

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-15-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 19:46:57 -07:00
Benjamin Tissoires
81f1d7a583 bpf: wq: add bpf_wq_set_callback_impl
To support sleepable async callbacks, we need to tell push_async_cb()
whether the cb is sleepable or not.

The verifier now detects that we are in bpf_wq_set_callback_impl and
can allow a sleepable callback to happen.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-13-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 19:46:57 -07:00
Benjamin Tissoires
eb48f6cd41 bpf: wq: add bpf_wq_init
We need to teach the verifier about the second argument which is declared
as void * but which is of type KF_ARG_PTR_TO_MAP. We could have dropped
this extra case if we declared the second argument as struct bpf_map *,
but that means users will have to do extra casting to have their program
compile.

We also need to duplicate the timer code for the checking if the map
argument is matching the provided workqueue.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-11-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 19:46:57 -07:00
Benjamin Tissoires
246331e3f1 bpf: allow struct bpf_wq to be embedded in arraymaps and hashmaps
Currently bpf_wq_cancel_and_free() is just a placeholder as there is
no memory allocation for bpf_wq just yet.

Again, duplication of the bpf_timer approach

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-9-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:25 -07:00
Benjamin Tissoires
d940c9b94d bpf: add support for KF_ARG_PTR_TO_WORKQUEUE
Introduce support for KF_ARG_PTR_TO_WORKQUEUE. The kfuncs will use bpf_wq
as argument and that will be recognized as workqueue argument by verifier.
bpf_wq_kern casting can happen inside kfunc, but using bpf_wq in
argument makes life easier for users who work with non-kern type in BPF
progs.

Duplicate process_timer_func into process_wq_func.
meta argument is only needed to ensure bpf_wq_init's workqueue and map
arguments are coming from the same map (map_uid logic is necessary for
correct inner-map handling), so also amend check_kfunc_args() to
match what helpers functions check is doing.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-8-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:25 -07:00
Benjamin Tissoires
ad2c03e691 bpf: verifier: bail out if the argument is not a map
When a kfunc is declared with a KF_ARG_PTR_TO_MAP, we should have
reg->map_ptr set to a non NULL value, otherwise, that means that the
underlying type is not a map.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-7-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Benjamin Tissoires
d56b63cf0c bpf: add support for bpf_wq user type
Mostly a copy/paste from the bpf_timer API, without the initialization
and free, as they will be done in a separate patch.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-5-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Benjamin Tissoires
fc22d9495f bpf: replace bpf_timer_cancel_and_free with a generic helper
Same reason than most bpf_timer* functions, we need almost the same for
workqueues.
So extract the generic part out of it so bpf_wq_cancel_and_free can reuse
it.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-4-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Benjamin Tissoires
073f11b026 bpf: replace bpf_timer_set_callback with a generic helper
In the same way we have a generic __bpf_async_init(), we also need
to share code between timer and workqueue for the set_callback call.

We just add an unused flags parameter, as it will be used for workqueues.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-3-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Benjamin Tissoires
56b4a177ae bpf: replace bpf_timer_init with a generic helper
No code change except for the new flags argument being stored in the
local data struct.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-2-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Benjamin Tissoires
be2749beff bpf: make timer data struct more generic
To be able to add workqueues and reuse most of the timer code, we need
to make bpf_hrtimer more generic.

There is no code change except that the new struct gets a new u64 flags
attribute. We are still below 2 cache lines, so this shouldn't impact
the current running codes.

The ordering is also changed. Everything related to async callback
is now on top of bpf_hrtimer.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-1-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-23 18:31:24 -07:00
Rafael Passos
a7de265cb2 bpf: Fix typos in comments
Found the following typos in comments, and fixed them:

s/unpriviledged/unprivileged/
s/reponsible/responsible/
s/possiblities/possibilities/
s/Divison/Division/
s/precsion/precision/
s/havea/have a/
s/reponsible/responsible/
s/responsibile/responsible/
s/tigher/tighter/
s/respecitve/respective/

Signed-off-by: Rafael Passos <rafael@rcpassos.me>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/6af7deb4-bb24-49e8-b3f1-8dd410597337@smtp-relay.sendinblue.com
2024-04-22 17:48:08 +02:00
Rafael Passos
e1a7545981 bpf: Fix typo in function save_aux_ptr_type
I found this typo in the save_aux_ptr_type function.
s/allow_trust_missmatch/allow_trust_mismatch/
I did not find this anywhere else in the codebase.

Signed-off-by: Rafael Passos <rafael@rcpassos.me>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/fbe1d636-8172-4698-9a5a-5a3444b55322@smtp-relay.sendinblue.com
2024-04-22 17:12:05 +02:00
Harishankar Vishwanathan
1f586614f3 bpf: Harden and/or/xor value tracking in verifier
This patch addresses a latent unsoundness issue in the
scalar(32)_min_max_and/or/xor functions. While it is not a bugfix,
it ensures that the functions produce sound outputs for all inputs.

The issue occurs in these functions when setting signed bounds. The
following example illustrates the issue for scalar_min_max_and(),
but it applies to the other functions.

In scalar_min_max_and() the following clause is executed when ANDing
positive numbers:

  /* ANDing two positives gives a positive, so safe to
   * cast result into s64.
   */
  dst_reg->smin_value = dst_reg->umin_value;
  dst_reg->smax_value = dst_reg->umax_value;

However, if umin_value and umax_value of dst_reg cross the sign boundary
(i.e., if (s64)dst_reg->umin_value > (s64)dst_reg->umax_value), then we
will end up with smin_value > smax_value, which is unsound.

Previous works [1, 2] have discovered and reported this issue. Our tool
Agni [2, 3] consideres it a false positive. This is because, during the
verification of the abstract operator scalar_min_max_and(), Agni restricts
its inputs to those passing through reg_bounds_sync(). This mimics
real-world verifier behavior, as reg_bounds_sync() is invariably executed
at the tail of every abstract operator. Therefore, such behavior is
unlikely in an actual verifier execution.

However, it is still unsound for an abstract operator to set signed bounds
such that smin_value > smax_value. This patch fixes it, making the abstract
operator sound for all (well-formed) inputs.

It is worth noting that while the previous code updated the signed bounds
(using the output unsigned bounds) only when the *input signed* bounds
were positive, the new code updates them whenever the *output unsigned*
bounds do not cross the sign boundary.

An alternative approach to fix this latent unsoundness would be to
unconditionally set the signed bounds to unbounded [S64_MIN, S64_MAX], and
let reg_bounds_sync() refine the signed bounds using the unsigned bounds
and the tnum. We found that our approach produces more precise (tighter)
bounds.

For example, consider these inputs to BPF_AND:

  /* dst_reg */
  var_off.value: 8608032320201083347
  var_off.mask: 615339716653692460
  smin_value: 8070450532247928832
  smax_value: 8070450532247928832
  umin_value: 13206380674380886586
  umax_value: 13206380674380886586
  s32_min_value: -2110561598
  s32_max_value: -133438816
  u32_min_value: 4135055354
  u32_max_value: 4135055354

  /* src_reg */
  var_off.value: 8584102546103074815
  var_off.mask: 9862641527606476800
  smin_value: 2920655011908158522
  smax_value: 7495731535348625717
  umin_value: 7001104867969363969
  umax_value: 8584102543730304042
  s32_min_value: -2097116671
  s32_max_value: 71704632
  u32_min_value: 1047457619
  u32_max_value: 4268683090

After going through tnum_and() -> scalar32_min_max_and() ->
scalar_min_max_and() -> reg_bounds_sync(), our patch produces the following
bounds for s32:

  s32_min_value: -1263875629
  s32_max_value: -159911942

Whereas, setting the signed bounds to unbounded in scalar_min_max_and()
produces:

  s32_min_value: -1263875629
  s32_max_value: -1

As observed, our patch produces a tighter s32 bound. We also confirmed
using Agni and SMT verification that our patch always produces signed
bounds that are equal to or more precise than setting the signed bounds to
unbounded in scalar_min_max_and().

  [1] https://sanjit-bhat.github.io/assets/pdf/ebpf-verifier-range-analysis22.pdf
  [2] https://link.springer.com/chapter/10.1007/978-3-031-37709-9_12
  [3] https://github.com/bpfverif/agni

Co-developed-by: Matan Shachnai <m.shachnai@rutgers.edu>
Signed-off-by: Matan Shachnai <m.shachnai@rutgers.edu>
Co-developed-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Signed-off-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Co-developed-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240402212039.51815-1-harishankar.vishwanathan@gmail.com
Link: https://lore.kernel.org/bpf/20240416115303.331688-1-harishankar.vishwanathan@gmail.com
2024-04-16 17:55:27 +02:00
Ard Biesheuvel
fc5eb4a84e btf: Avoid weak external references
If the BTF code is enabled in the build configuration, the start/stop
BTF markers are guaranteed to exist. Only when CONFIG_DEBUG_INFO_BTF=n,
the references in btf_parse_vmlinux() will remain unsatisfied, relying
on the weak linkage of the external references to avoid breaking the
build.

Avoid GOT based relocations to these markers in the final executable by
dropping the weak attribute and instead, make btf_parse_vmlinux() return
ERR_PTR(-ENOENT) directly if CONFIG_DEBUG_INFO_BTF is not enabled to
begin with.  The compiler will drop any subsequent references to
__start_BTF and __stop_BTF in that case, allowing the link to succeed.

Note that Clang will notice that taking the address of __start_BTF can
no longer yield NULL, so testing for that condition becomes unnecessary.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240415162041.2491523-8-ardb+git@google.com
2024-04-16 16:35:13 +02:00
Yonghong Song
699c23f02c bpf: Add bpf_link support for sk_msg and sk_skb progs
Add bpf_link support for sk_msg and sk_skb programs. We have an
internal request to support bpf_link for sk_msg programs so user
space can have a uniform handling with bpf_link based libbpf
APIs. Using bpf_link based libbpf API also has a benefit which
makes system robust by decoupling prog life cycle and
attachment life cycle.

Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240410043527.3737160-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-10 19:52:25 -07:00
Alexei Starovoitov
d503a04f8b bpf: Add support for certain atomics in bpf_arena to x86 JIT
Support atomics in bpf_arena that can be JITed as a single x86 instruction.
Instructions that are JITed as loops are not supported at the moment,
since they require more complex extable and loop logic.

JITs can choose to do smarter things with bpf_jit_supports_insn().
Like arm64 may decide to support all bpf atomics instructions
when emit_lse_atomic is available and none in ll_sc mode.

bpf_jit_supports_percpu_insn(), bpf_jit_supports_ptr_xchg() and
other such callbacks can be replaced with bpf_jit_supports_insn()
in the future.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240405231134.17274-1-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2024-04-09 10:24:26 -07:00
David Vernet
a8e03b6bbb bpf: Allow invoking kfuncs from BPF_PROG_TYPE_SYSCALL progs
Currently, a set of core BPF kfuncs (e.g. bpf_task_*, bpf_cgroup_*,
bpf_cpumask_*, etc) cannot be invoked from BPF_PROG_TYPE_SYSCALL
programs. The whitelist approach taken for enabling kfuncs makes sense:
it not safe to call these kfuncs from every program type. For example,
it may not be safe to call bpf_task_acquire() in an fentry to
free_task().

BPF_PROG_TYPE_SYSCALL, on the other hand, is a perfectly safe program
type from which to invoke these kfuncs, as it's a very controlled
environment, and we should never be able to run into any of the typical
problems such as recursive invoations, acquiring references on freeing
kptrs, etc. Being able to invoke these kfuncs would be useful, as
BPF_PROG_TYPE_SYSCALL can be invoked with BPF_PROG_RUN, and would
therefore enable user space programs to synchronously call into BPF to
manipulate these kptrs.

This patch therefore enables invoking the aforementioned core kfuncs
from BPF_PROG_TYPE_SYSCALL progs.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240405143041.632519-2-void@manifault.com
2024-04-05 10:56:09 -07:00
Philo Lu
9d482da9e1 bpf: allow invoking bpf_for_each_map_elem with different maps
Taking different maps within a single bpf_for_each_map_elem call is not
allowed before, because from the second map,
bpf_insn_aux_data->map_ptr_state will be marked as *poison*. In fact
both map_ptr and state are needed to support this use case: map_ptr is
used by set_map_elem_callback_state() while poison state is needed to
determine whether to use direct call.

Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240405025536.18113-3-lulie@linux.alibaba.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-05 10:31:17 -07:00
Philo Lu
0a525621b7 bpf: store both map ptr and state in bpf_insn_aux_data
Currently, bpf_insn_aux_data->map_ptr_state is used to store either
map_ptr or its poison state (i.e., BPF_MAP_PTR_POISON). Thus
BPF_MAP_PTR_POISON must be checked before reading map_ptr. In certain
cases, we may need valid map_ptr even in case of poison state.
This will be explained in next patch with bpf_for_each_map_elem()
helper.

This patch changes map_ptr_state into a new struct including both map
pointer and its state (poison/unpriv). It's in the same union with
struct bpf_loop_inline_state, so there is no extra memory overhead.
Besides, macros BPF_MAP_PTR_UNPRIV/BPF_MAP_PTR_POISON/BPF_MAP_PTR are no
longer needed.

This patch does not change any existing functionality.

Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240405025536.18113-2-lulie@linux.alibaba.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-05 10:31:17 -07:00
Arnd Bergmann
58babe2718 bpf: fix perf_snapshot_branch_stack link failure
The newly added code to handle bpf_get_branch_snapshot fails to link when
CONFIG_PERF_EVENTS is disabled:

aarch64-linux-ld: kernel/bpf/verifier.o: in function `do_misc_fixups':
verifier.c:(.text+0x1090c): undefined reference to `__SCK__perf_snapshot_branch_stack'

Add a build-time check for that Kconfig symbol around the code to
remove the link time dependency.

Fixes: 314a53623c ("bpf: inline bpf_get_branch_snapshot() helper")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240405142637.577046-1-arnd@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-05 08:39:15 -07:00
Andrii Nakryiko
1f2a74b41e bpf: prevent r10 register from being marked as precise
r10 is a special register that is not under BPF program's control and is
always effectively precise. The rest of precision logic assumes that
only r0-r9 SCALAR registers are marked as precise, so prevent r10 from
being marked precise.

This can happen due to signed cast instruction allowing to do something
like `r0 = (s8)r10;`, which later, if r0 needs to be precise, would lead
to an attempt to mark r10 as precise.

Prevent this with an extra check during instruction backtracking.

Fixes: 8100928c88 ("bpf: Support new sign-extension mov insns")
Reported-by: syzbot+148110ee7cf72f39f33e@syzkaller.appspotmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240404214536.3551295-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-04 18:31:08 -07:00
Andrii Nakryiko
314a53623c bpf: inline bpf_get_branch_snapshot() helper
Inline bpf_get_branch_snapshot() helper using architecture-agnostic
inline BPF code which calls directly into underlying callback of
perf_snapshot_branch_stack static call. This callback is set early
during kernel initialization and is never updated or reset, so it's ok
to fetch actual implementation using static_call_query() and call
directly into it.

This change eliminates a full function call and saves one LBR entry
in PERF_SAMPLE_BRANCH_ANY LBR mode.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240404002640.1774210-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-04 13:08:01 -07:00
Andrii Nakryiko
5e6a3c1ee6 bpf: make bpf_get_branch_snapshot() architecture-agnostic
perf_snapshot_branch_stack is set up in an architecture-agnostic way, so
there is no reason for BPF subsystem to keep track of which
architectures do support LBR or not. E.g., it looks like ARM64 might soon
get support for BRBE ([0]), which (with proper integration) should be
possible to utilize using this BPF helper.

perf_snapshot_branch_stack static call will point to
__static_call_return0() by default, which just returns zero, which will
lead to -ENOENT, as expected. So no need to guard anything here.

  [0] https://lore.kernel.org/linux-arm-kernel/20240125094119.2542332-1-anshuman.khandual@arm.com/

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240404002640.1774210-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-04 13:08:01 -07:00
Alexei Starovoitov
af682b767a bpf: Optimize emit_mov_imm64().
Turned out that bpf prog callback addresses, bpf prog addresses
used in bpf_trampoline, and in other cases the 64-bit address
can be represented as sign extended 32-bit value.

According to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82339
"Skylake has 0.64c throughput for mov r64, imm64, vs. 0.25 for mov r32, imm32."
So use shorter encoding and faster instruction when possible.

Special care is needed in jit_subprogs(), since bpf_pseudo_func()
instruction cannot change its size during the last step of JIT.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/CAADnVQKFfpY-QZBrOU2CG8v2du8Lgyb7MNVmOZVK_yTyOdNbBA@mail.gmail.com
Link: https://lore.kernel.org/bpf/20240401233800.42737-1-alexei.starovoitov@gmail.com
2024-04-04 16:13:26 +02:00
Andrii Nakryiko
0b56e637f7 bpf: inline bpf_map_lookup_elem() helper for PERCPU_HASH map
Using new per-CPU BPF instruction, partially inline
bpf_map_lookup_elem() helper for per-CPU hashmap BPF map. Just like for
normal HASH map, we still generate a call into __htab_map_lookup_elem(),
but after that we resolve per-CPU element address using a new
instruction, saving on extra functions calls.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-03 10:29:56 -07:00
Andrii Nakryiko
db69718b8e bpf: inline bpf_map_lookup_elem() for PERCPU_ARRAY maps
Using new per-CPU BPF instruction implement inlining for per-CPU ARRAY
map lookup helper, if BPF JIT support is present.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-03 10:29:56 -07:00
Andrii Nakryiko
1ae6921009 bpf: inline bpf_get_smp_processor_id() helper
If BPF JIT supports per-CPU MOV instruction, inline bpf_get_smp_processor_id()
to eliminate unnecessary function calls.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-03 10:29:56 -07:00
Andrii Nakryiko
7bdbf74463 bpf: add special internal-only MOV instruction to resolve per-CPU addrs
Add a new BPF instruction for resolving absolute addresses of per-CPU
data from their per-CPU offsets. This instruction is internal-only and
users are not allowed to use them directly. They will only be used for
internal inlining optimizations for now between BPF verifier and BPF JITs.

We use a special BPF_MOV | BPF_ALU64 | BPF_X form with insn->off field
set to BPF_ADDR_PERCPU = -1. I used negative offset value to distinguish
them from positive ones used by user-exposed instructions.

Such instruction performs a resolution of a per-CPU offset stored in
a register to a valid kernel address which can be dereferenced. It is
useful in any use case where absolute address of a per-CPU data has to
be resolved (e.g., in inlining bpf_map_lookup_elem()).

BPF disassembler is also taught to recognize them to support dumping
final BPF assembly code (non-JIT'ed version).

Add arch-specific way for BPF JITs to mark support for this instructions.

This patch also adds support for these instructions in x86-64 BPF JIT.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-03 10:29:55 -07:00
Justin Stitt
2e114248e0 bpf: Replace deprecated strncpy with strscpy
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

bpf sym names get looked up and compared/cleaned with various string
apis. This suggests they need to be NUL-terminated (strncpy() suggests
this but does not guarantee it).

|	static int compare_symbol_name(const char *name, char *namebuf)
|	{
|		cleanup_symbol_name(namebuf);
|		return strcmp(name, namebuf);
|	}

|	static void cleanup_symbol_name(char *s)
|	{
|		...
|		res = strstr(s, ".llvm.");
|		...
|	}

Use strscpy() as this method guarantees NUL-termination on the
destination buffer.

This patch also replaces two uses of strncpy() used in log.c. These are
simple replacements as postfix has been zero-initialized on the stack
and has source arguments with a size less than the destination's size.

Note that this patch uses the new 2-argument version of strscpy
introduced in commit e6584c3964 ("string: Allow 2-argument strscpy()").

Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Link: https://lore.kernel.org/bpf/20240402-strncpy-kernel-bpf-core-c-v1-1-7cb07a426e78@google.com
2024-04-03 16:57:41 +02:00
Jose Fernandez
ce09cbdd98 bpf: Improve program stats run-time calculation
This patch improves the run-time calculation for program stats by
capturing the duration as soon as possible after the program returns.

Previously, the duration included u64_stats_t operations. While the
instrumentation overhead is part of the total time spent when stats are
enabled, distinguishing between the program's native execution time and
the time spent due to instrumentation is crucial for accurate
performance analysis.

By making this change, the patch facilitates more precise optimization
of BPF programs, enabling users to understand their performance in
environments without stats enabled.

I used a virtualized environment to measure the run-time over one minute
for a basic raw_tracepoint/sys_enter program, which just increments a
local counter. Although the virtualization introduced some performance
degradation that could affect the results, I observed approximately a
16% decrease in average run-time reported by stats with this change
(310 -> 260 nsec).

Signed-off-by: Jose Fernandez <josef@netflix.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240402034010.25060-1-josef@netflix.com
2024-04-02 16:51:15 +02:00
Anton Protopopov
9dc182c58b bpf: Add a verbose message if map limit is reached
When more than 64 maps are used by a program and its subprograms the
verifier returns -E2BIG. Add a verbose message which highlights the
source of the error and also print the actual limit.

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240402073347.195920-1-aspsk@isovalent.com
2024-04-02 16:12:00 +02:00
Alexei Starovoitov
59f2f84117 bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie.
syzbot reported the following lock sequence:
cpu 2:
  grabs timer_base lock
    spins on bpf_lpm lock

cpu 1:
  grab rcu krcp lock
    spins on timer_base lock

cpu 0:
  grab bpf_lpm lock
    spins on rcu krcp lock

bpf_lpm lock can be the same.
timer_base lock can also be the same due to timer migration.
but rcu krcp lock is always per-cpu, so it cannot be the same lock.
Hence it's a false positive.
To avoid lockdep complaining move kfree_rcu() after spin_unlock.

Reported-by: syzbot+1fa663a2100308ab6eab@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240329171439.37813-1-alexei.starovoitov@gmail.com
2024-03-29 11:10:41 -07:00
Martin KaFai Lau
e8742081db bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode
syzbot reported uninit memory usages during map_{lookup,delete}_elem.

==========
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
__dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
==========

The reproducer should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

    0: (18) r0 = 0x0
    2: (18) r1 = map[id:49]
    4: (b7) r8 = 16777216
    5: (7b) *(u64 *)(r10 -8) = r8
    6: (bf) r2 = r10
    7: (07) r2 += -229
            ^^^^^^^^^^

    8: (b7) r3 = 8
    9: (b7) r4 = 0
   10: (85) call dev_map_lookup_elem#1543472
   11: (95) exit

It is due to the "void *key" (r2) passed to the helper. bpf allows uninit
stack memory access for bpf prog with the right privileges. This patch
uses kmsan_unpoison_memory() to mark the stack as initialized.

This should address different syzbot reports on the uninit "void *key"
argument during map_{lookup,delete}_elem.

Reported-by: syzbot+603bcd9b0bf1d94dbb9b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000f9ce6d061494e694@google.com/
Reported-by: syzbot+eb02dc7f03dce0ef39f3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000a5c69c06147c2238@google.com/
Reported-by: syzbot+b4e65ca24fd4d0c734c3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000ac56fb06143b6cfa@google.com/
Reported-by: syzbot+d2b113dc9fea5e1d2848@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000000d69b206142d1ff7@google.com/
Reported-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000006f876b061478e878@google.com/
Tested-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Suggested-by: Yonghong Song <yonghong.song@linux.dev>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240328185801.1843078-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-28 19:00:59 -07:00
Yafang Shao
ee3bad033d bpf: Mitigate latency spikes associated with freeing non-preallocated htab
Following the recent upgrade of one of our BPF programs, we encountered
significant latency spikes affecting other applications running on the same
host. After thorough investigation, we identified that these spikes were
primarily caused by the prolonged duration required to free a
non-preallocated htab with approximately 2 million keys.

Notably, our kernel configuration lacks the presence of CONFIG_PREEMPT. In
scenarios where kernel execution extends excessively, other threads might
be starved of CPU time, resulting in latency issues across the system. To
mitigate this, we've adopted a proactive approach by incorporating
cond_resched() calls within the kernel code. This ensures that during
lengthy kernel operations, the scheduler is invoked periodically to provide
opportunities for other threads to execute.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240327032022.78391-1-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-28 18:31:40 -07:00
Andrii Nakryiko
3124591f68 bpf: add bpf_modify_return_test_tp() kfunc triggering tracepoint
Add a simple bpf_modify_return_test_tp() kfunc, available to all program
types, that is useful for various testing and benchmarking scenarios, as
it allows to trigger most tracing BPF program types from BPF side,
allowing to do complex testing and benchmarking scenarios.

It is also attachable to for fmod_ret programs, making it a good and
simple way to trigger fmod_ret program under test/benchmark.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240326162151.3981687-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-28 18:31:40 -07:00
Haiyue Wang
55fc888ded bpf,arena: Use helper sizeof_field in struct accessors
Use the well defined helper sizeof_field() to calculate the size of a
struct member, instead of doing custom calculations.

Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Link: https://lore.kernel.org/r/20240327065334.8140-1-haiyue.wang@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-28 18:31:36 -07:00
Mykyta Yatsenko
786bf0e7e2 bpf: improve error message for unsupported helper
BPF verifier emits "unknown func" message when given BPF program type
does not support BPF helper. This message may be confusing for users, as
important context that helper is unknown only to current program type is
not provided.

This patch changes message to "program of this type cannot use helper "
and aligns dependent code in libbpf and tests. Any suggestions on
improving/changing this message are welcome.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/r/20240325152210.377548-1-yatsenko@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-28 18:30:53 -07:00
Jakub Kicinski
5e47fbe5ce Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts, or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-28 17:25:57 -07:00
Linus Torvalds
50108c352d Merge tag 'net-6.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
 "Including fixes from bpf, WiFi and netfilter.

  Current release - regressions:

   - ipv6: fix address dump when IPv6 is disabled on an interface

  Current release - new code bugs:

   - bpf: temporarily disable atomic operations in BPF arena

   - nexthop: fix uninitialized variable in nla_put_nh_group_stats()

  Previous releases - regressions:

   - bpf: protect against int overflow for stack access size

   - hsr: fix the promiscuous mode in offload mode

   - wifi: don't always use FW dump trig

   - tls: adjust recv return with async crypto and failed copy to
     userspace

   - tcp: properly terminate timers for kernel sockets

   - ice: fix memory corruption bug with suspend and rebuild

   - at803x: fix kernel panic with at8031_probe

   - qeth: handle deferred cc1

  Previous releases - always broken:

   - bpf: fix bug in BPF_LDX_MEMSX

   - netfilter: reject table flag and netdev basechain updates

   - inet_defrag: prevent sk release while still in use

   - wifi: pick the version of SESSION_PROTECTION_NOTIF

   - wwan: t7xx: split 64bit accesses to fix alignment issues

   - mlxbf_gige: call request_irq() after NAPI initialized

   - hns3: fix kernel crash when devlink reload during pf
     initialization"

* tag 'net-6.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (81 commits)
  inet: inet_defrag: prevent sk release while still in use
  Octeontx2-af: fix pause frame configuration in GMP mode
  net: lan743x: Add set RFE read fifo threshold for PCI1x1x chips
  net: bcmasp: Remove phy_{suspend/resume}
  net: bcmasp: Bring up unimac after PHY link up
  net: phy: qcom: at803x: fix kernel panic with at8031_probe
  netfilter: arptables: Select NETFILTER_FAMILY_ARP when building arp_tables.c
  netfilter: nf_tables: skip netdev hook unregistration if table is dormant
  netfilter: nf_tables: reject table flag and netdev basechain updates
  netfilter: nf_tables: reject destroy command to remove basechain hooks
  bpf: update BPF LSM designated reviewer list
  bpf: Protect against int overflow for stack access size
  bpf: Check bloom filter map value size
  bpf: fix warning for crash_kexec
  selftests: netdevsim: set test timeout to 10 minutes
  net: wan: framer: Add missing static inline qualifiers
  mlxbf_gige: call request_irq() after NAPI initialized
  tls: get psock ref after taking rxlock to avoid leak
  selftests: tls: add test with a partially invalid iov
  tls: adjust recv return with async crypto and failed copy to userspace
  ...
2024-03-28 13:09:37 -07:00
Linus Torvalds
dc189b8e6a Merge tag 'mm-hotfixes-stable-2024-03-27-11-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
 "Various hotfixes. About half are cc:stable and the remainder address
  post-6.8 issues or aren't considered suitable for backporting.

  zswap figures prominently in the post-6.8 issues - folloup against the
  large amount of changes we have just made to that code.

  Apart from that, all over the map"

* tag 'mm-hotfixes-stable-2024-03-27-11-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
  crash: use macro to add crashk_res into iomem early for specific arch
  mm: zswap: fix data loss on SWP_SYNCHRONOUS_IO devices
  selftests/mm: fix ARM related issue with fork after pthread_create
  hexagon: vmlinux.lds.S: handle attributes section
  userfaultfd: fix deadlock warning when locking src and dst VMAs
  tmpfs: fix race on handling dquot rbtree
  selftests/mm: sigbus-wp test requires UFFD_FEATURE_WP_HUGETLBFS_SHMEM
  mm: zswap: fix writeback shinker GFP_NOIO/GFP_NOFS recursion
  ARM: prctl: reject PR_SET_MDWE on pre-ARMv6
  prctl: generalize PR_SET_MDWE support check to be per-arch
  MAINTAINERS: remove incorrect M: tag for dm-devel@lists.linux.dev
  mm: zswap: fix kernel BUG in sg_init_one
  selftests: mm: restore settings from only parent process
  tools/Makefile: remove cgroup target
  mm: cachestat: fix two shmem bugs
  mm: increase folio batch size
  mm,page_owner: fix recursion
  mailmap: update entry for Leonard Crestez
  init: open /initrd.image with O_LARGEFILE
  selftests/mm: Fix build with _FORTIFY_SOURCE
  ...
2024-03-27 13:30:48 -07:00
Linus Torvalds
962490525c Merge tag 'probes-fixes-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fixlet from Masami Hiramatsu:

 - tracing/probes: initialize a 'val' local variable with zero.

   This variable is read by FETCH_OP_ST_EDATA in a loop, and is
   initialized by FETCH_OP_ARG in the same loop. Since this
   initialization is not obvious, smatch warns about it.

   Explicitly initializing 'val' with zero fixes this warning.

* tag 'probes-fixes-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: probes: Fix to zero initialize a local variable
2024-03-27 10:01:24 -07:00
Andrei Matei
ecc6a21018 bpf: Protect against int overflow for stack access size
This patch re-introduces protection against the size of access to stack
memory being negative; the access size can appear negative as a result
of overflowing its signed int representation. This should not actually
happen, as there are other protections along the way, but we should
protect against it anyway. One code path was missing such protections
(fixed in the previous patch in the series), causing out-of-bounds array
accesses in check_stack_range_initialized(). This patch causes the
verification of a program with such a non-sensical access size to fail.

This check used to exist in a more indirect way, but was inadvertendly
removed in a833a17aea.

Fixes: a833a17aea ("bpf: Fix verification of indirect var-off stack access")
Reported-by: syzbot+33f4297b5f927648741a@syzkaller.appspotmail.com
Reported-by: syzbot+aafd0513053a1cbf52ef@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/CAADnVQLORV5PT0iTAhRER+iLBTkByCYNBYyvBSgjN1T31K+gOw@mail.gmail.com/
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Link: https://lore.kernel.org/r/20240327024245.318299-3-andreimatei1@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-27 09:56:36 -07:00
Andrei Matei
a8d89feba7 bpf: Check bloom filter map value size
This patch adds a missing check to bloom filter creating, rejecting
values above KMALLOC_MAX_SIZE. This brings the bloom map in line with
many other map types.

The lack of this protection can cause kernel crashes for value sizes
that overflow int's. Such a crash was caught by syzkaller. The next
patch adds more guard-rails at a lower level.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240327024245.318299-2-andreimatei1@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-27 09:56:17 -07:00
Linus Torvalds
5b4cdd9c56 Fix memory leak in posix_clock_open()
If the clk ops.open() function returns an error, we don't release the
pccontext we allocated for this clock.

Re-organize the code slightly to make it all more obvious.

Reported-by: Rohit Keshri <rkeshri@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 60c6946675 ("posix-clock: introduce posix_clock_context concept")
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linuxfoundation.org>
2024-03-27 09:03:22 -07:00
Hari Bathini
96b98a6552 bpf: fix warning for crash_kexec
With [1], crash dump specific code is moved out of CONFIG_KEXEC_CORE
and placed under CONFIG_CRASH_DUMP, where it is more appropriate.
And since CONFIG_KEXEC & !CONFIG_CRASH_DUMP build option is supported
with that, it led to the below warning:

  "WARN: resolve_btfids: unresolved symbol crash_kexec"

Fix it by using the appropriate #ifdef.

[1] https://lore.kernel.org/all/20240124051254.67105-1-bhe@redhat.com/

Acked-by: Baoquan He <bhe@redhat.com>
Fixes: 02aff84805 ("crash: split crash dumping code out from kexec_core.c")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Link: https://lore.kernel.org/r/20240319080152.36987-1-hbathini@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-27 08:52:24 -07:00
Jakub Kicinski
2a702c2e57 Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2024-03-25

We've added 38 non-merge commits during the last 13 day(s) which contain
a total of 50 files changed, 867 insertions(+), 274 deletions(-).

The main changes are:

1) Add the ability to specify and retrieve BPF cookie also for raw
   tracepoint programs in order to ease migration from classic to raw
   tracepoints, from Andrii Nakryiko.

2) Allow the use of bpf_get_{ns_,}current_pid_tgid() helper for all
   program types and add additional BPF selftests, from Yonghong Song.

3) Several improvements to bpftool and its build, for example, enabling
   libbpf logs when loading pid_iter in debug mode, from Quentin Monnet.

4) Check the return code of all BPF-related set_memory_*() functions during
   load and bail out in case they fail, from Christophe Leroy.

5) Avoid a goto in regs_refine_cond_op() such that the verifier can
   be better integrated into Agni tool which doesn't support backedges
   yet, from Harishankar Vishwanathan.

6) Add a small BPF trie perf improvement by always inlining
   longest_prefix_match, from Jesper Dangaard Brouer.

7) Small BPF selftest refactor in bpf_tcp_ca.c to utilize start_server()
   helper instead of open-coding it, from Geliang Tang.

8) Improve test_tc_tunnel.sh BPF selftest to prevent client connect
   before the server bind, from Alessandro Carminati.

9) Fix BPF selftest benchmark for older glibc and use syscall(SYS_gettid)
   instead of gettid(), from Alan Maguire.

10) Implement a backward-compatible method for struct_ops types with
    additional fields which are not present in older kernels,
    from Kui-Feng Lee.

11) Add a small helper to check if an instruction is addr_space_cast
    from as(0) to as(1) and utilize it in x86-64 JIT, from Puranjay Mohan.

12) Small cleanup to remove unnecessary error check in
    bpf_struct_ops_map_update_elem, from Martin KaFai Lau.

13) Improvements to libbpf fd validity checks for BPF map/programs,
    from Mykyta Yatsenko.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (38 commits)
  selftests/bpf: Fix flaky test btf_map_in_map/lookup_update
  bpf: implement insn_is_cast_user() helper for JITs
  bpf: Avoid get_kernel_nofault() to fetch kprobe entry IP
  selftests/bpf: Use start_server in bpf_tcp_ca
  bpf: Sync uapi bpf.h to tools directory
  libbpf: Add new sec_def "sk_skb/verdict"
  selftests/bpf: Mark uprobe trigger functions with nocf_check attribute
  selftests/bpf: Use syscall(SYS_gettid) instead of gettid() wrapper in bench
  bpf-next: Avoid goto in regs_refine_cond_op()
  bpftool: Clean up HOST_CFLAGS, HOST_LDFLAGS for bootstrap bpftool
  selftests/bpf: scale benchmark counting by using per-CPU counters
  bpftool: Remove unnecessary source files from bootstrap version
  bpftool: Enable libbpf logs when loading pid_iter in debug mode
  selftests/bpf: add raw_tp/tp_btf BPF cookie subtests
  libbpf: add support for BPF cookie for raw_tp/tp_btf programs
  bpf: support BPF cookie in raw tracepoint (raw_tp, tp_btf) programs
  bpf: pass whole link instead of prog when triggering raw tracepoint
  bpf: flatten bpf_probe_register call chain
  selftests/bpf: Prevent client connect before server bind in test_tc_tunnel.sh
  selftests/bpf: Add a sk_msg prog bpf_get_ns_current_pid_tgid() test
  ...
====================

Link: https://lore.kernel.org/r/20240325233940.7154-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-27 07:52:34 -07:00
Baoquan He
32fbe52465 crash: use macro to add crashk_res into iomem early for specific arch
There are regression reports[1][2] that crashkernel region on x86_64 can't
be added into iomem tree sometime.  This causes the later failure of kdump
loading.

This happened after commit 4a693ce65b ("kdump: defer the insertion of
crashkernel resources") was merged.

Even though, these reported issues are proved to be related to other
component, they are just exposed after above commmit applied, I still
would like to keep crashk_res and crashk_low_res being added into iomem
early as before because the early adding has been always there on x86_64
and working very well.  For safety of kdump, Let's change it back.

Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
only ARCH defining the macro can have the early adding
crashk_res/_low_res into iomem. Then define
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.

Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
handling which was mistakenly added back in commit 85fcde402d ("kexec:
split crashkernel reservation code out from crash_core.c").

[1]
[PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
https://lore.kernel.org/all/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T/#u

[2]
Question about Address Range Validation in Crash Kernel Allocation
https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u

Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv
Fixes: 4a693ce65b ("kdump: defer the insertion of crashkernel resources")
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-26 11:14:12 -07:00
Zev Weiss
d5aad4c2ca prctl: generalize PR_SET_MDWE support check to be per-arch
Patch series "ARM: prctl: Reject PR_SET_MDWE where not supported".

I noticed after a recent kernel update that my ARM926 system started
segfaulting on any execve() after calling prctl(PR_SET_MDWE).  After some
investigation it appears that ARMv5 is incapable of providing the
appropriate protections for MDWE, since any readable memory is also
implicitly executable.

The prctl_set_mdwe() function already had some special-case logic added
disabling it on PARISC (commit 793838138c, "prctl: Disable
prctl(PR_SET_MDWE) on parisc"); this patch series (1) generalizes that
check to use an arch_*() function, and (2) adds a corresponding override
for ARM to disable MDWE on pre-ARMv6 CPUs.

With the series applied, prctl(PR_SET_MDWE) is rejected on ARMv5 and
subsequent execve() calls (as well as mmap(PROT_READ|PROT_WRITE)) can
succeed instead of unconditionally failing; on ARMv6 the prctl works as it
did previously.

[0] https://lore.kernel.org/all/2023112456-linked-nape-bf19@gregkh/


This patch (of 2):

There exist systems other than PARISC where MDWE may not be feasible to
support; rather than cluttering up the generic code with additional
arch-specific logic let's add a generic function for checking MDWE support
and allow each arch to override it as needed.

Link: https://lkml.kernel.org/r/20240227013546.15769-4-zev@bewilderbeest.net
Link: https://lkml.kernel.org/r/20240227013546.15769-5-zev@bewilderbeest.net
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Acked-by: Helge Deller <deller@gmx.de>	[parisc]
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Florent Revest <revest@chromium.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sam James <sam@gentoo.org>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: <stable@vger.kernel.org>	[6.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-26 11:07:22 -07:00
Linus Torvalds
7033999ecd Merge tag 'printk-for-6.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk fix from Petr Mladek:

 - Prevent scheduling in an atomic context when printk() takes over the
   console flushing duty

* tag 'printk-for-6.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Update @console_may_schedule in console_trylock_spinning()
2024-03-26 09:25:57 -07:00