Alexei Starovoitov says:

====================
pull-request: bpf-next 2022-03-21 v2

We've added 137 non-merge commits during the last 17 day(s) which contain
a total of 143 files changed, 7123 insertions(+), 1092 deletions(-).

The main changes are:

1) Custom SEC() handling in libbpf, from Andrii.

2) subskeleton support, from Delyan.

3) Use btf_tag to recognize __percpu pointers in the verifier, from Hao.

4) Fix net.core.bpf_jit_harden race, from Hou.

5) Fix bpf_sk_lookup remote_port on big-endian, from Jakub.

6) Introduce fprobe (multi kprobe) _without_ arch bits, from Masami.
The arch specific bits will come later.

7) Introduce multi_kprobe bpf programs on top of fprobe, from Jiri.

8) Enable non-atomic allocations in local storage, from Joanne.

9) Various var_off ptr_to_btf_id fixed, from Kumar.

10) bpf_ima_file_hash helper, from Roberto.

11) Add "live packet" mode for XDP in BPF_PROG_RUN, from Toke.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (137 commits)
  selftests/bpf: Fix kprobe_multi test.
  Revert "rethook: x86: Add rethook x86 implementation"
  Revert "arm64: rethook: Add arm64 rethook implementation"
  Revert "powerpc: Add rethook support"
  Revert "ARM: rethook: Add rethook arm implementation"
  bpftool: Fix a bug in subskeleton code generation
  bpf: Fix bpf_prog_pack when PMU_SIZE is not defined
  bpf: Fix bpf_prog_pack for multi-node setup
  bpf: Fix warning for cast from restricted gfp_t in verifier
  bpf, arm: Fix various typos in comments
  libbpf: Close fd in bpf_object__reuse_map
  bpftool: Fix print error when show bpf map
  bpf: Fix kprobe_multi return probe backtrace
  Revert "bpf: Add support to inline bpf_get_func_ip helper on x86"
  bpf: Simplify check in btf_parse_hdr()
  selftests/bpf/test_lirc_mode2.sh: Exit with proper code
  bpf: Check for NULL return from bpf_get_btf_vmlinux
  selftests/bpf: Test skipping stacktrace
  bpf: Adjust BPF stack helper functions to accommodate skip > 0
  bpf: Select proper size for bpf_prog_pack
  ...
====================

Link: https://lore.kernel.org/r/20220322050159.5507-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/dsa/dsa2.c
  commit afb3cc1a397d ("net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails")
  commit e83d56537859 ("net: dsa: replay master state events in dsa_tree_{setup,teardown}_master")
https://lore.kernel.org/all/20220307101436.7ae87da0@canb.auug.org.au/

drivers/net/ethernet/intel/ice/ice.h
  commit 97b0129146b1 ("ice: Fix error with handling of bonding MTU")
  commit 43113ff73453 ("ice: add TTY for GNSS module for E810T device")
https://lore.kernel.org/all/20220310112843.3233bcf1@canb.auug.org.au/

drivers/staging/gdm724x/gdm_lte.c
  commit fc7f750dc9d1 ("staging: gdm724x: fix use after free in gdm_lte_rx()")
  commit 4bcc4249b4cf ("staging: Use netif_rx().")
https://lore.kernel.org/all/20220308111043.1018a59d@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull x86 spectre fixes from Borislav Petkov:

 - Mitigate Spectre v2-type Branch History Buffer attacks on machines
   which support eIBRS, i.e., the hardware-assisted speculation
   restriction after it has been shown that such machines are vulnerable
   even with the hardware mitigation.

 - Do not use the default LFENCE-based Spectre v2 mitigation on AMD as
   it is insufficient to mitigate such attacks. Instead, switch to
   retpolines on all AMD by default.

 - Update the docs and add some warnings for the obviously vulnerable
   cmdline configurations.

* tag 'x86_bugs_for_v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
  x86/speculation: Warn about Spectre v2 LFENCE mitigation
  x86/speculation: Update link to AMD speculation whitepaper
  x86/speculation: Use generic retpoline by default on AMD
  x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
  Documentation/hw-vuln: Update spectre doc
  x86/speculation: Add eIBRS + Retpoline options
  x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE

With the introduction of the btf_type_tag "percpu", we can add a
MEM_PERCPU to identify those pointers that point to percpu memory.
The ability of differetiating percpu pointers from regular memory
pointers have two benefits:

 1. It forbids unexpected use of percpu pointers, such as direct loads.
    In kernel, there are special functions used for accessing percpu
    memory. Directly loading percpu memory is meaningless. We already
    have BPF helpers like bpf_per_cpu_ptr() and bpf_this_cpu_ptr() that
    wrap the kernel percpu functions. So we can now convert percpu
    pointers into regular pointers in a safe way.

 2. Previously, bpf_per_cpu_ptr() and bpf_this_cpu_ptr() only work on
    PTR_TO_PERCPU_BTF_ID, a special reg_type which describes static
    percpu variables in kernel (we rely on pahole to encode them into
    vmlinux BTF). Now, since we can identify __percpu tagged pointers,
    we can also identify dynamically allocated percpu memory as well.
    It means we can use bpf_xxx_cpu_ptr() on dynamic percpu memory.
    This would be very convenient when accessing fields like
    "cgroup->rstat_cpu".

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-4-haoluo@google.com

With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable
to Spectre v2 BHB-based attacks.

When both are enabled, print a warning message and report it in the
'spectre_v2' sysfs vulnerabilities file.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Fast path bpf marge for some -next work.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The patch in [1] intends to fix a bpf_timer related issue,
but the fix caused existing 'timer' selftest to fail with
hang or some random errors. After some debug, I found
an issue with check_and_init_map_value() in the hashtab.c.
More specifically, in hashtab.c, we have code
  l_new = bpf_map_kmalloc_node(&htab->map, ...)
  check_and_init_map_value(&htab->map, l_new...)
Note that bpf_map_kmalloc_node() does not do initialization
so l_new contains random value.

The function check_and_init_map_value() intends to zero the
bpf_spin_lock and bpf_timer if they exist in the map.
But I found bpf_spin_lock is zero'ed but bpf_timer is not zero'ed.
With [1], later copy_map_value() skips copying of
bpf_spin_lock and bpf_timer. The non-zero bpf_timer caused
random failures for 'timer' selftest.
Without [1], for both bpf_spin_lock and bpf_timer case,
bpf_timer will be zero'ed, so 'timer' self test is okay.

For check_and_init_map_value(), why bpf_spin_lock is zero'ed
properly while bpf_timer not. In bpf uapi header, we have
  struct bpf_spin_lock {
        __u32   val;
  };
  struct bpf_timer {
        __u64 :64;
        __u64 :64;
  } __attribute__((aligned(8)));

The initialization code:
  *(struct bpf_spin_lock *)(dst + map->spin_lock_off) =
      (struct bpf_spin_lock){};
  *(struct bpf_timer *)(dst + map->timer_off) =
      (struct bpf_timer){};
It appears the compiler has no obligation to initialize anonymous fields.
For example, let us use clang with bpf target as below:
  $ cat t.c
  struct bpf_timer {
        unsigned long long :64;
  };
  struct bpf_timer2 {
        unsigned long long a;
  };

  void test(struct bpf_timer *t) {
    *t = (struct bpf_timer){};
  }
  void test2(struct bpf_timer2 *t) {
    *t = (struct bpf_timer2){};
  }
  $ clang -target bpf -O2 -c -g t.c
  $ llvm-objdump -d t.o
   ...
   0000000000000000 <test>:
       0:       95 00 00 00 00 00 00 00 exit
   0000000000000008 <test2>:
       1:       b7 02 00 00 00 00 00 00 r2 = 0
       2:       7b 21 00 00 00 00 00 00 *(u64 *)(r1 + 0) = r2
       3:       95 00 00 00 00 00 00 00 exit

gcc11.2 does not have the above issue. But from
  INTERNATIONAL STANDARD ©ISO/IEC ISO/IEC 9899:201x
  Programming languages — C
  http://www.open-std.org/Jtc1/sc22/wg14/www/docs/n1547.pdf
  page 157:
  Except where explicitly stated otherwise, for the purposes of
  this subclause unnamed members of objects of structure and union
  type do not participate in initialization. Unnamed members of
  structure objects have indeterminate value even after initialization.

To fix the problem, let use memset for bpf_timer case in
check_and_init_map_value(). For consistency, memset is also
used for bpf_spin_lock case.

  [1] https://lore.kernel.org/bpf/20220209070324.1093182-2-memxor@gmail.com/

Fixes: 68134668c17f3 ("bpf: Add map side support for bpf timers.")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220211194953.3142152-1-yhs@fb.com

When both bpf_spin_lock and bpf_timer are present in a BPF map value,
copy_map_value needs to skirt both objects when copying a value into and
out of the map. However, the current code does not set both s_off and
t_off in copy_map_value, which leads to a crash when e.g. bpf_spin_lock
is placed in map value with bpf_timer, as bpf_map_update_elem call will
be able to overwrite the other timer object.

When the issue is not fixed, an overwriting can produce the following
splat:

[root@(none) bpf]# ./test_progs -t timer_crash
[   15.930339] bpf_testmod: loading out-of-tree module taints kernel.
[   16.037849] ==================================================================
[   16.038458] BUG: KASAN: user-memory-access in __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.038944] Write of size 8 at addr 0000000000043ec0 by task test_progs/325
[   16.039399]
[   16.039514] CPU: 0 PID: 325 Comm: test_progs Tainted: G           OE     5.16.0+ #278
[   16.039983] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.15.0-1 04/01/2014
[   16.040485] Call Trace:
[   16.040645]  <TASK>
[   16.040805]  dump_stack_lvl+0x59/0x73
[   16.041069]  ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.041427]  kasan_report.cold+0x116/0x11b
[   16.041673]  ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.042040]  __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.042328]  ? memcpy+0x39/0x60
[   16.042552]  ? pv_hash+0xd0/0xd0
[   16.042785]  ? lockdep_hardirqs_off+0x95/0xd0
[   16.043079]  __bpf_spin_lock_irqsave+0xdf/0xf0
[   16.043366]  ? bpf_get_current_comm+0x50/0x50
[   16.043608]  ? jhash+0x11a/0x270
[   16.043848]  bpf_timer_cancel+0x34/0xe0
[   16.044119]  bpf_prog_c4ea1c0f7449940d_sys_enter+0x7c/0x81
[   16.044500]  bpf_trampoline_6442477838_0+0x36/0x1000
[   16.044836]  __x64_sys_nanosleep+0x5/0x140
[   16.045119]  do_syscall_64+0x59/0x80
[   16.045377]  ? lock_is_held_type+0xe4/0x140
[   16.045670]  ? irqentry_exit_to_user_mode+0xa/0x40
[   16.046001]  ? mark_held_locks+0x24/0x90
[   16.046287]  ? asm_exc_page_fault+0x1e/0x30
[   16.046569]  ? asm_exc_page_fault+0x8/0x30
[   16.046851]  ? lockdep_hardirqs_on+0x7e/0x100
[   16.047137]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   16.047405] RIP: 0033:0x7f9e4831718d
[   16.047602] Code: b4 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b3 6c 0c 00 f7 d8 64 89 01 48
[   16.048764] RSP: 002b:00007fff488086b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000023
[   16.049275] RAX: ffffffffffffffda RBX: 00007f9e48683740 RCX: 00007f9e4831718d
[   16.049747] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fff488086d0
[   16.050225] RBP: 00007fff488086f0 R08: 00007fff488085d7 R09: 00007f9e4cb594a0
[   16.050648] R10: 0000000000000000 R11: 0000000000000206 R12: 00007f9e484cde30
[   16.051124] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   16.051608]  </TASK>
[   16.051762] ==================================================================

Fixes: 68134668c17f ("bpf: Add map side support for bpf timers.")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220209070324.1093182-2-memxor@gmail.com

This is the jit binary allocator built on top of bpf_prog_pack.

bpf_prog_pack allocates RO memory, which cannot be used directly by the
JIT engine. Therefore, a temporary rw buffer is allocated for the JIT
engine. Once JIT is done, bpf_jit_binary_pack_finalize is used to copy
the program to the RO memory.

bpf_jit_binary_pack_alloc reserves 16 bytes of extra space for illegal
instructions, which is small than the 128 bytes space reserved by
bpf_jit_binary_alloc. This change is necessary for bpf_jit_binary_hdr
to find the correct header. Also, flag use_bpf_prog_pack is added to
differentiate a program allocated by bpf_jit_binary_pack_alloc.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-9-song@kernel.org

This will be used to copy JITed text to RO protected module memory. On
x86, bpf_arch_text_copy is implemented with text_poke_copy.

bpf_arch_text_copy returns pointer to dst on success, and ERR_PTR(errno)
on errors.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-7-song@kernel.org