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Martin KaFai Lau c39028b333 libbpf: btf_dump_type_data_check_overflow needs to consider BTF_MEMBER_BITFIELD_SIZE 
The btf_dump/struct_data selftest is failing with:

  [...]
  test_btf_dump_struct_data:FAIL:unexpected return value dumping fs_context unexpected unexpected return value dumping fs_context: actual -7 != expected 264
  [...]

The reason is in btf_dump_type_data_check_overflow(). It does not use
BTF_MEMBER_BITFIELD_SIZE from the struct's member (btf_member). Instead,
it is using the enum size which is 4. It had been working till the recent
commit 4e04143c86 ("fs_context: drop the unused lsm_flags member")
removed an integer member which also removed the 4 bytes padding at the
end of the fs_context. Missing this 4 bytes padding exposed this bug. In
particular, when btf_dump_type_data_check_overflow() reaches the member
'phase', -E2BIG is returned.

The fix is to pass bit_sz to btf_dump_type_data_check_overflow(). In
btf_dump_type_data_check_overflow(), it does a different size check when
bit_sz is not zero.

The current fs_context:

[3600] ENUM 'fs_context_purpose' encoding=UNSIGNED size=4 vlen=3
	'FS_CONTEXT_FOR_MOUNT' val=0
	'FS_CONTEXT_FOR_SUBMOUNT' val=1
	'FS_CONTEXT_FOR_RECONFIGURE' val=2
[3601] ENUM 'fs_context_phase' encoding=UNSIGNED size=4 vlen=7
	'FS_CONTEXT_CREATE_PARAMS' val=0
	'FS_CONTEXT_CREATING' val=1
	'FS_CONTEXT_AWAITING_MOUNT' val=2
	'FS_CONTEXT_AWAITING_RECONF' val=3
	'FS_CONTEXT_RECONF_PARAMS' val=4
	'FS_CONTEXT_RECONFIGURING' val=5
	'FS_CONTEXT_FAILED' val=6
[3602] STRUCT 'fs_context' size=264 vlen=21
	'ops' type_id=3603 bits_offset=0
	'uapi_mutex' type_id=235 bits_offset=64
	'fs_type' type_id=872 bits_offset=1216
	'fs_private' type_id=21 bits_offset=1280
	'sget_key' type_id=21 bits_offset=1344
	'root' type_id=781 bits_offset=1408
	'user_ns' type_id=251 bits_offset=1472
	'net_ns' type_id=984 bits_offset=1536
	'cred' type_id=1785 bits_offset=1600
	'log' type_id=3621 bits_offset=1664
	'source' type_id=42 bits_offset=1792
	'security' type_id=21 bits_offset=1856
	's_fs_info' type_id=21 bits_offset=1920
	'sb_flags' type_id=20 bits_offset=1984
	'sb_flags_mask' type_id=20 bits_offset=2016
	's_iflags' type_id=20 bits_offset=2048
	'purpose' type_id=3600 bits_offset=2080 bitfield_size=8
	'phase' type_id=3601 bits_offset=2088 bitfield_size=8
	'need_free' type_id=67 bits_offset=2096 bitfield_size=1
	'global' type_id=67 bits_offset=2097 bitfield_size=1
	'oldapi' type_id=67 bits_offset=2098 bitfield_size=1

Fixes: 920d16af9b ("libbpf: BTF dumper support for typed data")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230428013638.1581263-1-martin.lau@linux.dev
2023-05-01 15:37:38 +02:00
arch Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
block for-6.4/block-2023-04-21 2023-04-26 12:52:58 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto This update includes the following changes: 2023-04-26 08:32:52 -07:00
Documentation docs/bpf: Add LRU internals description and graph 2023-04-27 14:20:44 +02:00
drivers igc: Add XDP hints kfuncs for RX timestamp 2023-04-27 18:42:19 +02:00
fs Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
include xsk: Use pool->dma_pages to check for DMA 2023-04-27 22:24:51 +02:00
init slab changes for 6.4 2023-04-25 13:00:41 -07:00
io_uring Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel bpf: Add bpf_dynptr_clone 2023-04-27 10:40:47 +02:00
lib Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
net xsk: Use pool->dma_pages to check for DMA 2023-04-27 22:24:51 +02:00
rust rust: allow to use INIT_STACK_ALL_ZERO 2023-04-19 19:34:43 +02:00
samples Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
scripts Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
security Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
sound iter-ubuf.2-2023-04-21 2023-04-24 10:29:28 -07:00
tools libbpf: btf_dump_type_data_check_overflow needs to consider BTF_MEMBER_BITFIELD_SIZE 2023-05-01 15:37:38 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE platform dependent 2023-03-31 11:19:05 -04:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap Networking fixes for 6.3-rc8, including fixes from netfilter and bpf 2023-04-20 11:03:51 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS qnx4: credit contributors in CREDITS 2023-03-14 12:56:30 -06:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking changes for 6.4. 2023-04-26 16:07:23 -07:00
Makefile Linux 6.3 2023-04-23 12:02:52 -07:00
README

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.