linux.git/kernel/bpf, branch v6.9-rc2

Merge tag 'kbuild-fixes-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-03-31T18:23:51+00:00

Pull Kbuild fixes from Masahiro Yamada:

 - Deduplicate Kconfig entries for CONFIG_CXL_PMU

 - Fix unselectable choice entry in MIPS Kconfig, and forbid this
   structure

 - Remove unused include/asm-generic/export.h

 - Fix a NULL pointer dereference bug in modpost

 - Enable -Woverride-init warning consistently with W=1

 - Drop KCSAN flags from *.mod.c files

* tag 'kbuild-fixes-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: Fix typo HEIGTH to HEIGHT
  Documentation/llvm: Note s390 LLVM=1 support with LLVM 18.1.0 and newer
  kbuild: Disable KCSAN for autogenerated *.mod.c intermediaries
  kbuild: make -Woverride-init warnings more consistent
  modpost: do not make find_tosym() return NULL
  export.h: remove include/asm-generic/export.h
  kconfig: do not reparent the menu inside a choice block
  MIPS: move unselectable FIT_IMAGE_FDT_EPM5 out of the "System type" choice
  cxl: remove CONFIG_CXL_PMU entry in drivers/cxl/Kconfig

kbuild: make -Woverride-init warnings more consistent

2024-03-31T02:32:26+00:00

The -Woverride-init warn about code that may be intentional or not,
but the inintentional ones tend to be real bugs, so there is a bit of
disagreement on whether this warning option should be enabled by default
and we have multiple settings in scripts/Makefile.extrawarn as well as
individual subsystems.

Older versions of clang only supported -Wno-initializer-overrides with
the same meaning as gcc's -Woverride-init, though all supported versions
now work with both. Because of this difference, an earlier cleanup of
mine accidentally turned the clang warning off for W=1 builds and only
left it on for W=2, while it's still enabled for gcc with W=1.

There is also one driver that only turns the warning off for newer
versions of gcc but not other compilers, and some but not all the
Makefiles still use a cc-disable-warning conditional that is no
longer needed with supported compilers here.

Address all of the above by removing the special cases for clang
and always turning the warning off unconditionally where it got
in the way, using the syntax that is supported by both compilers.

Fixes: 2cd3271b7a31 ("kbuild: avoid duplicate warning options")
Signed-off-by: Arnd Bergmann 
Acked-by: Hamza Mahfooz 
Acked-by: Jani Nikula 
Acked-by: Andrew Jeffery 
Signed-off-by: Jani Nikula 
Reviewed-by: Linus Walleij 
Signed-off-by: Masahiro Yamada

bpf: Protect against int overflow for stack access size

2024-03-27T16:56:36+00:00

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 a833a17aeac7.

Fixes: a833a17aeac7 ("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 
Signed-off-by: Andrei Matei 
Link: https://lore.kernel.org/r/20240327024245.318299-3-andreimatei1@gmail.com
Signed-off-by: Alexei Starovoitov

bpf: Check bloom filter map value size

2024-03-27T16:56:17+00:00

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 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20240327024245.318299-2-andreimatei1@gmail.com
Signed-off-by: Alexei Starovoitov

bpf: fix warning for crash_kexec

2024-03-27T15:52:24+00:00

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 
Fixes: 02aff8480533 ("crash: split crash dumping code out from kexec_core.c")
Acked-by: Jiri Olsa 
Acked-by: Stanislav Fomichev 
Signed-off-by: Hari Bathini 
Link: https://lore.kernel.org/r/20240319080152.36987-1-hbathini@linux.ibm.com
Signed-off-by: Alexei Starovoitov

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2024-03-26T11:55:18+00:00

Daniel Borkmann says:

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

The following pull-request contains BPF updates for your *net* tree.

We've added 17 non-merge commits during the last 12 day(s) which contain
a total of 19 files changed, 184 insertions(+), 61 deletions(-).

The main changes are:

1) Fix an arm64 BPF JIT bug in BPF_LDX_MEMSX implementation's offset handling
   found via test_bpf module, from Puranjay Mohan.

2) Various fixups to the BPF arena code in particular in the BPF verifier and
   around BPF selftests to match latest corresponding LLVM implementation,
   from Puranjay Mohan and Alexei Starovoitov.

3) Fix xsk to not assume that metadata is always requested in TX completion,
   from Stanislav Fomichev.

4) Fix riscv BPF JIT's kfunc parameter incompatibility between BPF and the riscv
   ABI which requires sign-extension on int/uint, from Pu Lehui.

5) Fix s390x BPF JIT's bpf_plt pointer arithmetic which triggered a crash when
   testing struct_ops, from Ilya Leoshkevich.

6) Fix libbpf's arena mmap handling which had incorrect u64-to-pointer cast on
   32-bit architectures, from Andrii Nakryiko.

7) Fix libbpf to define MFD_CLOEXEC when not available, from Arnaldo Carvalho de Melo.

8) Fix arm64 BPF JIT implementation for 32bit unconditional bswap which
   resulted in an incorrect swap as indicated by test_bpf, from Artem Savkov.

9) Fix BPF man page build script to use silent mode, from Hangbin Liu.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  riscv, bpf: Fix kfunc parameters incompatibility between bpf and riscv abi
  bpf: verifier: reject addr_space_cast insn without arena
  selftests/bpf: verifier_arena: fix mmap address for arm64
  bpf: verifier: fix addr_space_cast from as(1) to as(0)
  libbpf: Define MFD_CLOEXEC if not available
  arm64: bpf: fix 32bit unconditional bswap
  bpf, arm64: fix bug in BPF_LDX_MEMSX
  libbpf: fix u64-to-pointer cast on 32-bit arches
  s390/bpf: Fix bpf_plt pointer arithmetic
  xsk: Don't assume metadata is always requested in TX completion
  selftests/bpf: Add arena test case for 4Gbyte corner case
  selftests/bpf: Remove hard coded PAGE_SIZE macro.
  libbpf, selftests/bpf: Adjust libbpf, bpftool, selftests to match LLVM
  bpf: Clarify bpf_arena comments.
  MAINTAINERS: Update email address for Quentin Monnet
  scripts/bpf_doc: Use silent mode when exec make cmd
  bpf: Temporarily disable atomic operations in BPF arena
====================

Link: https://lore.kernel.org/r/20240325213520.26688-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni

bpf: verifier: reject addr_space_cast insn without arena

2024-03-23T03:44:09+00:00

The verifier allows using the addr_space_cast instruction in a program
that doesn't have an associated arena. This was caught in the form an
invalid memory access in do_misc_fixups() when while converting
addr_space_cast to a normal 32-bit mov, env->prog->aux->arena was
dereferenced to check for BPF_F_NO_USER_CONV flag.

Reject programs that include the addr_space_cast instruction but don't
have an associated arena.

root@rv-tester:~# ./reproducer
 Unable to handle kernel access to user memory without uaccess routines at virtual address 0000000000000030
 Oops [#1]
 [] do_misc_fixups+0x43c/0x1168
 [] bpf_check+0xda8/0x22b6
 [] bpf_prog_load+0x486/0x8dc
 [] __sys_bpf+0xbd8/0x214e
 [] __riscv_sys_bpf+0x22/0x2a
 [] do_trap_ecall_u+0x102/0x17c
 [] ret_from_exception+0x0/0x64

Fixes: 6082b6c328b5 ("bpf: Recognize addr_space_cast instruction in the verifier.")
Reported-by: xingwei lee 
Reported-by: yue sun 
Closes: https://lore.kernel.org/bpf/CABOYnLz09O1+2gGVJuCxd_24a-7UueXzV-Ff+Fr+h5EKFDiYCQ@mail.gmail.com/
Signed-off-by: Puranjay Mohan 
Link: https://lore.kernel.org/r/20240322153518.11555-1-puranjay12@gmail.com
Signed-off-by: Alexei Starovoitov

bpf: verifier: fix addr_space_cast from as(1) to as(0)

2024-03-23T03:36:36+00:00

The verifier currently converts addr_space_cast from as(1) to as(0) that
is: BPF_ALU64 | BPF_MOV | BPF_X with off=1 and imm=1
to
BPF_ALU | BPF_MOV | BPF_X with imm=1 (32-bit mov)

Because of this imm=1, the JITs that have bpf_jit_needs_zext() == true,
interpret the converted instruction as BPF_ZEXT_REG(DST) which is a
special form of mov32, used for doing explicit zero extension on dst.
These JITs will just zero extend the dst reg and will not move the src to
dst before the zext.

Fix do_misc_fixups() to set imm=0 when converting addr_space_cast to a
normal mov32.

The JITs that have bpf_jit_needs_zext() == true rely on the verifier to
emit zext instructions. Mark dst_reg as subreg when doing cast from
as(1) to as(0) so the verifier emits a zext instruction after the mov.

Fixes: 6082b6c328b5 ("bpf: Recognize addr_space_cast instruction in the verifier.")
Signed-off-by: Puranjay Mohan 
Link: https://lore.kernel.org/r/20240321153939.113996-1-puranjay12@gmail.com
Signed-off-by: Alexei Starovoitov

bpf: report RCU QS in cpumap kthread

2024-03-21T04:05:43+00:00

When there are heavy load, cpumap kernel threads can be busy polling
packets from redirect queues and block out RCU tasks from reaching
quiescent states. It is insufficient to just call cond_resched() in such
context. Periodically raise a consolidated RCU QS before cond_resched
fixes the problem.

Fixes: 6710e1126934 ("bpf: introduce new bpf cpu map type BPF_MAP_TYPE_CPUMAP")
Reviewed-by: Jesper Dangaard Brouer 
Signed-off-by: Yan Zhai 
Acked-by: Paul E. McKenney 
Acked-by: Jesper Dangaard Brouer 
Link: https://lore.kernel.org/r/c17b9f1517e19d813da3ede5ed33ee18496bb5d8.1710877680.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski

bpf: Clarify bpf_arena comments.

2024-03-15T21:23:45+00:00

Clarify two bpf_arena comments, use existing SZ_4G #define,
improve page_cnt check.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Andrii Nakryiko 
Acked-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20240315021834.62988-2-alexei.starovoitov@gmail.com