linux-stable.git/tools/lib/bpf, branch v5.7.9

libbpf: Support pre-initializing .bss global variables

2020-06-24T15:49:11+00:00

[ Upstream commit caf62492f479585296e9d636c798d5ac256b7b04 ]

Remove invalid assumption in libbpf that .bss map doesn't have to be updated
in kernel. With addition of skeleton and memory-mapped initialization image,
.bss doesn't have to be all zeroes when BPF map is created, because user-code
might have initialized those variables from user-space.

Fixes: eba9c5f498a1 ("libbpf: Refactor global data map initialization")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200612194504.557844-1-andriin@fb.com
Signed-off-by: Sasha Levin

libbpf: Handle GCC noreturn-turned-volatile quirk

2020-06-24T15:49:09+00:00

[ Upstream commit 32022fd97ed34f6812802bf1288db27c313576f4 ]

Handle a GCC quirk of emitting extra volatile modifier in DWARF (and
subsequently preserved in BTF by pahole) for function pointers marked as
__attribute__((noreturn)). This was the way to mark such functions before GCC
2.5 added noreturn attribute. Drop such func_proto modifiers, similarly to how
it's done for array (also to handle GCC quirk/bug).

Such volatile attribute is emitted by GCC only, so existing selftests can't
express such test. Simple repro is like this (compiled with GCC + BTF
generated by pahole):

  struct my_struct {
      void __attribute__((noreturn)) (*fn)(int);
  };
  struct my_struct a;

Without this fix, output will be:

struct my_struct {
    voidvolatile  (*fn)(int);
};

With the fix:

struct my_struct {
    void (*fn)(int);
};

Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: Jean-Philippe Brucker 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Tested-by: Jean-Philippe Brucker 
Link: https://lore.kernel.org/bpf/20200610052335.2862559-1-andriin@fb.com
Signed-off-by: Sasha Levin

libbpf: Fix perf_buffer__free() API for sparse allocs

2020-06-22T07:32:53+00:00

[ Upstream commit 601b05ca6edb0422bf6ce313fbfd55ec7bbbc0fd ]

In case the cpu_bufs are sparsely allocated they are not all
free'ed. These changes will fix this.

Fixes: fb84b8224655 ("libbpf: add perf buffer API")
Signed-off-by: Eelco Chaudron 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/159056888305.330763.9684536967379110349.stgit@ebuild
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

libbpf: Fix huge memory leak in libbpf_find_vmlinux_btf_id()

2020-06-22T07:32:34+00:00

[ Upstream commit 3521ffa2ee9a48c3236c93f54ae11c074490ebce ]

BTF object wasn't freed.

Fixes: a6ed02cac690 ("libbpf: Load btf_vmlinux only once per object.")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Cc: KP Singh 
Link: https://lore.kernel.org/bpf/20200429012111.277390-9-andriin@fb.com
Signed-off-by: Sasha Levin

libbpf: Refactor map creation logic and fix cleanup leak

2020-06-22T07:32:33+00:00

[ Upstream commit 2d39d7c56f115148b05d1d8c6b8698a5730c8b53 ]

Factor out map creation and destruction logic to simplify code and especially
error handling. Also fix map FD leak in case of partially successful map
creation during bpf_object load operation.

Fixes: 57a00f41644f ("libbpf: Add auto-pinning of maps when loading BPF objects")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20200429002739.48006-3-andriin@fb.com
Signed-off-by: Sasha Levin

libbpf: Fix memory leak and possible double-free in hashmap__clear

2020-06-22T07:32:19+00:00

[ Upstream commit 229bf8bf4d910510bc1a2fd0b89bd467cd71050d ]

Fix memory leak in hashmap_clear() not freeing hashmap_entry structs for each
of the remaining entries. Also NULL-out bucket list to prevent possible
double-free between hashmap__clear() and hashmap__free().

Running test_progs-asan flavor clearly showed this problem.

Reported-by: Alston Tang 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200429012111.277390-5-andriin@fb.com
Signed-off-by: Sasha Levin

libbpf: Fix register naming in PT_REGS s390 macros

2020-05-14T19:44:17+00:00

Fix register naming in PT_REGS s390 macros

Fixes: b8ebce86ffe6 ("libbpf: Provide CO-RE variants of PT_REGS macros")
Signed-off-by: Sumanth Korikkar 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Julian Wiedmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200513154414.29972-1-sumanthk@linux.ibm.com

libbpf: Only check mode flags in get_xdp_id

2020-04-23T05:07:22+00:00

The commit in the Fixes tag changed get_xdp_id to only return prog_id
if flags is 0, but there are other XDP flags than the modes - e.g.,
XDP_FLAGS_UPDATE_IF_NOEXIST. Since the intention was only to look at
MODE flags, clear other ones before checking if flags is 0.

Fixes: f07cbad29741 ("libbpf: Fix bpf_get_link_xdp_id flags handling")
Signed-off-by: David Ahern 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrey Ignatov

libbpf: Fix type of old_fd in bpf_xdp_set_link_opts

2020-04-15T11:26:08+00:00

The 'old_fd' parameter used for atomic replacement of XDP programs is
supposed to be an FD, but was left as a u32 from an earlier iteration of
the patch that added it. It was converted to an int when read, so things
worked correctly even with negative values, but better change the
definition to correctly reflect the intention.

Fixes: bd5ca3ef93cd ("libbpf: Add function to set link XDP fd while specifying old program")
Reported-by: David Ahern 
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Daniel Borkmann 
Acked-by: David Ahern 
Acked-by: Song Liu 
Link: https://lore.kernel.org/bpf/20200414145025.182163-1-toke@redhat.com

libbpf: Always specify expected_attach_type on program load if supported

2020-04-15T11:22:43+00:00

For some types of BPF programs that utilize expected_attach_type, libbpf won't
set load_attr.expected_attach_type, even if expected_attach_type is known from
section definition. This was done to preserve backwards compatibility with old
kernels that didn't recognize expected_attach_type attribute yet (which was
added in 5e43f899b03a ("bpf: Check attach type at prog load time"). But this
is problematic for some BPF programs that utilize newer features that require
kernel to know specific expected_attach_type (e.g., extended set of return
codes for cgroup_skb/egress programs).

This patch makes libbpf specify expected_attach_type by default, but also
detect support for this field in kernel and not set it during program load.
This allows to have a good metadata for bpf_program
(e.g., bpf_program__get_extected_attach_type()), but still work with old
kernels (for cases where it can work at all).

Additionally, due to expected_attach_type being always set for recognized
program types, bpf_program__attach_cgroup doesn't have to do extra checks to
determine correct attach type, so remove that additional logic.

Also adjust section_names selftest to account for this change.

More detailed discussion can be found in [0].

  [0] https://lore.kernel.org/bpf/20200412003604.GA15986@rdna-mbp.dhcp.thefacebook.com/

Fixes: 5cf1e9145630 ("bpf: cgroup inet skb programs can return 0 to 3")
Fixes: 5e43f899b03a ("bpf: Check attach type at prog load time")
Reported-by: Andrey Ignatov 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Song Liu 
Acked-by: Andrey Ignatov 
Link: https://lore.kernel.org/bpf/20200414182645.1368174-1-andriin@fb.com