linux.git/kernel/bpf, branch v6.6-rc4

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2023-09-16T10:16:00+00:00

Alexei Starovoitov says:

====================

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

We've added 21 non-merge commits during the last 8 day(s) which contain
a total of 21 files changed, 450 insertions(+), 36 deletions(-).

The main changes are:

1) Adjust bpf_mem_alloc buckets to match ksize(), from Hou Tao.

2) Check whether override is allowed in kprobe mult, from Jiri Olsa.

3) Fix btf_id symbol generation with ld.lld, from Jiri and Nick.

4) Fix potential deadlock when using queue and stack maps from NMI, from Toke Høiland-Jørgensen.

Please consider pulling these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git

Thanks a lot!

Also thanks to reporters, reviewers and testers of commits in this pull-request:

Alan Maguire, Biju Das, Björn Töpel, Dan Carpenter, Daniel Borkmann,
Eduard Zingerman, Hsin-Wei Hung, Marcus Seyfarth, Nathan Chancellor,
Satya Durga Srinivasu Prabhala, Song Liu, Stephen Rothwell
====================

Signed-off-by: David S. Miller

bpf: Skip unit_size checking for global per-cpu allocator

2023-09-15T17:22:24+00:00

For global per-cpu allocator, the size of free object in free list
doesn't match with unit_size and now there is no way to get the size of
per-cpu pointer saved in free object, so just skip the checking.

Reported-by: Stephen Rothwell 
Closes: https://lore.kernel.org/bpf/20230913133436.0eeec4cb@canb.auug.org.au/
Signed-off-by: Hou Tao 
Tested-by: Biju Das 
Link: https://lore.kernel.org/r/20230913135943.3137292-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov

bpf, cgroup: fix multiple kernel-doc warnings

2023-09-12T20:19:07+00:00

Fix missing or extra function parameter kernel-doc warnings
in cgroup.c:

kernel/bpf/cgroup.c:1359: warning: Excess function parameter 'type' description in '__cgroup_bpf_run_filter_skb'
kernel/bpf/cgroup.c:1359: warning: Function parameter or member 'atype' not described in '__cgroup_bpf_run_filter_skb'
kernel/bpf/cgroup.c:1439: warning: Excess function parameter 'type' description in '__cgroup_bpf_run_filter_sk'
kernel/bpf/cgroup.c:1439: warning: Function parameter or member 'atype' not described in '__cgroup_bpf_run_filter_sk'
kernel/bpf/cgroup.c:1467: warning: Excess function parameter 'type' description in '__cgroup_bpf_run_filter_sock_addr'
kernel/bpf/cgroup.c:1467: warning: Function parameter or member 'atype' not described in '__cgroup_bpf_run_filter_sock_addr'
kernel/bpf/cgroup.c:1512: warning: Excess function parameter 'type' description in '__cgroup_bpf_run_filter_sock_ops'
kernel/bpf/cgroup.c:1512: warning: Function parameter or member 'atype' not described in '__cgroup_bpf_run_filter_sock_ops'
kernel/bpf/cgroup.c:1685: warning: Excess function parameter 'type' description in '__cgroup_bpf_run_filter_sysctl'
kernel/bpf/cgroup.c:1685: warning: Function parameter or member 'atype' not described in '__cgroup_bpf_run_filter_sysctl'
kernel/bpf/cgroup.c:795: warning: Excess function parameter 'type' description in '__cgroup_bpf_replace'
kernel/bpf/cgroup.c:795: warning: Function parameter or member 'new_prog' not described in '__cgroup_bpf_replace'

Signed-off-by: Randy Dunlap 
Cc: Martin KaFai Lau 
Cc: bpf@vger.kernel.org
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20230912060812.1715-1-rdunlap@infradead.org
Signed-off-by: Alexei Starovoitov

bpf: Fix a erroneous check after snprintf()

2023-09-12T20:15:46+00:00

snprintf() does not return negative error code on error, it returns the
number of characters which *would* be generated for the given input.

Fix the error handling check.

Fixes: 57539b1c0ac2 ("bpf: Enable annotating trusted nested pointers")
Signed-off-by: Christophe JAILLET 
Link: https://lore.kernel.org/r/393bdebc87b22563c08ace094defa7160eb7a6c0.1694190795.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Alexei Starovoitov

bpf: Avoid dummy bpf_offload_netdev in __bpf_prog_dev_bound_init

2023-09-12T05:06:06+00:00

Fix for a bug observable under the following sequence of events:
1. Create a network device that does not support XDP offload.
2. Load a device bound XDP program with BPF_F_XDP_DEV_BOUND_ONLY flag
   (such programs are not offloaded).
3. Load a device bound XDP program with zero flags
   (such programs are offloaded).

At step (2) __bpf_prog_dev_bound_init() associates with device (1)
a dummy bpf_offload_netdev struct with .offdev field set to NULL.
At step (3) __bpf_prog_dev_bound_init() would reuse dummy struct
allocated at step (2).
However, downstream usage of the bpf_offload_netdev assumes that
.offdev field can't be NULL, e.g. in bpf_prog_offload_verifier_prep().

Adjust __bpf_prog_dev_bound_init() to require bpf_offload_netdev
with non-NULL .offdev for offloaded BPF programs.

Fixes: 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs")
Reported-by: syzbot+291100dcb32190ec02a8@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000d97f3c060479c4f8@google.com/
Signed-off-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20230912005539.2248244-2-eddyz87@gmail.com
Signed-off-by: Martin KaFai Lau

bpf: Avoid deadlock when using queue and stack maps from NMI

2023-09-12T02:04:49+00:00

Sysbot discovered that the queue and stack maps can deadlock if they are
being used from a BPF program that can be called from NMI context (such as
one that is attached to a perf HW counter event). To fix this, add an
in_nmi() check and use raw_spin_trylock() in NMI context, erroring out if
grabbing the lock fails.

Fixes: f1a2e44a3aec ("bpf: add queue and stack maps")
Reported-by: Hsin-Wei Hung 
Tested-by: Hsin-Wei Hung 
Co-developed-by: Hsin-Wei Hung 
Signed-off-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/r/20230911132815.717240-1-toke@redhat.com
Signed-off-by: Alexei Starovoitov

bpf: Ensure unit_size is matched with slab cache object size

2023-09-11T19:41:37+00:00

Add extra check in bpf_mem_alloc_init() to ensure the unit_size of
bpf_mem_cache is matched with the object_size of underlying slab cache.
If these two sizes are unmatched, print a warning once and return
-EINVAL in bpf_mem_alloc_init(), so the mismatch can be found early and
the potential issue can be prevented.

Suggested-by: Alexei Starovoitov 
Signed-off-by: Hou Tao 
Link: https://lore.kernel.org/r/20230908133923.2675053-4-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov

bpf: Don't prefill for unused bpf_mem_cache

2023-09-11T19:41:37+00:00

When the unit_size of a bpf_mem_cache is unmatched with the object_size
of the underlying slab cache, the bpf_mem_cache will not be used, and
the allocation will be redirected to a bpf_mem_cache with a bigger
unit_size instead, so there is no need to prefill for these
unused bpf_mem_caches.

Signed-off-by: Hou Tao 
Link: https://lore.kernel.org/r/20230908133923.2675053-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov

bpf: Adjust size_index according to the value of KMALLOC_MIN_SIZE

2023-09-11T19:41:36+00:00

The following warning was reported when running "./test_progs -a
link_api -a linked_list" on a RISC-V QEMU VM:

  ------------[ cut here ]------------
  WARNING: CPU: 3 PID: 261 at kernel/bpf/memalloc.c:342 bpf_mem_refill
  Modules linked in: bpf_testmod(OE)
  CPU: 3 PID: 261 Comm: test_progs- ... 6.5.0-rc5-01743-gdcb152bb8328 #2
  Hardware name: riscv-virtio,qemu (DT)
  epc : bpf_mem_refill+0x1fc/0x206
   ra : irq_work_single+0x68/0x70
  epc : ffffffff801b1bc4 ra : ffffffff8015fe84 sp : ff2000000001be20
   gp : ffffffff82d26138 tp : ff6000008477a800 t0 : 0000000000046600
   t1 : ffffffff812b6ddc t2 : 0000000000000000 s0 : ff2000000001be70
   s1 : ff5ffffffffe8998 a0 : ff5ffffffffe8998 a1 : ff600003fef4b000
   a2 : 000000000000003f a3 : ffffffff80008250 a4 : 0000000000000060
   a5 : 0000000000000080 a6 : 0000000000000000 a7 : 0000000000735049
   s2 : ff5ffffffffe8998 s3 : 0000000000000022 s4 : 0000000000001000
   s5 : 0000000000000007 s6 : ff5ffffffffe8570 s7 : ffffffff82d6bd30
   s8 : 000000000000003f s9 : ffffffff82d2c5e8 s10: 000000000000ffff
   s11: ffffffff82d2c5d8 t3 : ffffffff81ea8f28 t4 : 0000000000000000
   t5 : ff6000008fd28278 t6 : 0000000000040000
  [] bpf_mem_refill+0x1fc/0x206
  [] irq_work_single+0x68/0x70
  [] irq_work_run_list+0x28/0x36
  [] irq_work_run+0x38/0x66
  [] handle_IPI+0x3a/0xb4
  [] handle_percpu_devid_irq+0xa4/0x1f8
  [] generic_handle_domain_irq+0x28/0x36
  [] ipi_mux_process+0xac/0xfa
  [] sbi_ipi_handle+0x2e/0x88
  [] generic_handle_domain_irq+0x28/0x36
  [] riscv_intc_irq+0x36/0x4e
  [] handle_riscv_irq+0x54/0x86
  [] do_irq+0x66/0x98
  ---[ end trace 0000000000000000 ]---

The warning is due to WARN_ON_ONCE(tgt->unit_size != c->unit_size) in
free_bulk(). The direct reason is that a object is allocated and
freed by bpf_mem_caches with different unit_size.

The root cause is that KMALLOC_MIN_SIZE is 64 and there is no 96-bytes
slab cache in the specific VM. When linked_list test allocates a
72-bytes object through bpf_obj_new(), bpf_global_ma will allocate it
from a bpf_mem_cache with 96-bytes unit_size, but this bpf_mem_cache is
backed by 128-bytes slab cache. When the object is freed, bpf_mem_free()
uses ksize() to choose the corresponding bpf_mem_cache. Because the
object is allocated from 128-bytes slab cache, ksize() returns 128,
bpf_mem_free() chooses a 128-bytes bpf_mem_cache to free the object and
triggers the warning.

A similar warning will also be reported when using CONFIG_SLAB instead
of CONFIG_SLUB in a x86-64 kernel. Because CONFIG_SLUB defines
KMALLOC_MIN_SIZE as 8 but CONFIG_SLAB defines KMALLOC_MIN_SIZE as 32.

An alternative fix is to use kmalloc_size_round() in bpf_mem_alloc() to
choose a bpf_mem_cache which has the same unit_size with the backing
slab cache, but it may introduce performance degradation, so fix the
warning by adjusting the indexes in size_index according to the value of
KMALLOC_MIN_SIZE just like setup_kmalloc_cache_index_table() does.

Fixes: 822fb26bdb55 ("bpf: Add a hint to allocated objects.")
Reported-by: Björn Töpel 
Closes: https://lore.kernel.org/bpf/87jztjmmy4.fsf@all.your.base.are.belong.to.us
Signed-off-by: Hou Tao 
Link: https://lore.kernel.org/r/20230908133923.2675053-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov

Merge tag 'riscv-for-linus-6.6-mw2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2023-09-09T21:25:11+00:00

Pull more RISC-V updates from Palmer Dabbelt:

 - The kernel now dynamically probes for misaligned access speed, as
   opposed to relying on a table of known implementations.

 - Support for non-coherent devices on systems using the Andes AX45MP
   core, including the RZ/Five SoCs.

 - Support for the V extension in ptrace(), again.

 - Support for KASLR.

 - Support for the BPF prog pack allocator in RISC-V.

 - A handful of bug fixes and cleanups.

* tag 'riscv-for-linus-6.6-mw2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (25 commits)
  soc: renesas: Kconfig: For ARCH_R9A07G043 select the required configs if dependencies are met
  riscv: Kconfig.errata: Add dependency for RISCV_SBI in ERRATA_ANDES config
  riscv: Kconfig.errata: Drop dependency for MMU in ERRATA_ANDES_CMO config
  riscv: Kconfig: Select DMA_DIRECT_REMAP only if MMU is enabled
  bpf, riscv: use prog pack allocator in the BPF JIT
  riscv: implement a memset like function for text
  riscv: extend patch_text_nosync() for multiple pages
  bpf: make bpf_prog_pack allocator portable
  riscv: libstub: Implement KASLR by using generic functions
  libstub: Fix compilation warning for rv32
  arm64: libstub: Move KASLR handling functions to kaslr.c
  riscv: Dump out kernel offset information on panic
  riscv: Introduce virtual kernel mapping KASLR
  RISC-V: Add ptrace support for vectors
  soc: renesas: Kconfig: Select the required configs for RZ/Five SoC
  cache: Add L2 cache management for Andes AX45MP RISC-V core
  dt-bindings: cache: andestech,ax45mp-cache: Add DT binding documentation for L2 cache controller
  riscv: mm: dma-noncoherent: nonstandard cache operations support
  riscv: errata: Add Andes alternative ports
  riscv: asm: vendorid_list: Add Andes Technology to the vendors list
  ...