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9440c42941
With just the forward declaration of the 'struct pt_regs' in
syscall_wrapper.h, the syscall stub functions:
__[x64|ia32]_sys_*(struct pt_regs *regs)
will have different definition of 'regs' argument in BTF data
based on which object file they are defined in.
If the syscall's object includes 'struct pt_regs' definition,
the BTF argument data will point to a 'struct pt_regs' record,
like:
[226] STRUCT 'pt_regs' size=168 vlen=21
'r15' type_id=1 bits_offset=0
'r14' type_id=1 bits_offset=64
'r13' type_id=1 bits_offset=128
...
If not, it will point to a fwd declaration record:
[15439] FWD 'pt_regs' fwd_kind=struct
and make bpf tracing program hooking on those functions unable
to access fields from 'struct pt_regs'.
Include asm/ptrace.h directly in syscall_wrapper.h to make sure all
syscalls see 'struct pt_regs' definition. This then results in BTF for
'__*_sys_*(struct pt_regs *regs)' functions to point to the actual
struct, not just the forward declaration.
[ bp: No Fixes tag as this is not really a bug fix but "adjustment" so
that BTF is happy. ]
Reported-by: Akihiro HARAI <jharai0815@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: <stable@vger.kernel.org> # this is needed only for BTF so kernels >= 5.15
Link: https://lore.kernel.org/r/20221018122708.823792-1-jolsa@kernel.org
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.