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12e6196fb1
Commitafbf21dce6("bpf: Support readonly/readwrite buffers in verifier") added readonly/readwrite buffer support which is currently used by bpf_iter tracing programs. It has a bug with incorrect parameter ordering which later fixed by Commitf6dfbe31e8("bpf: Fix swapped arguments in calls to check_buffer_access"). This patch added a test case with a negative offset access which will trigger the error path. Without Commitf6dfbe31e8, running the test case in the patch, the error message looks like: R1_w=rdwr_buf(id=0,off=0,imm=0) R10=fp0 ; value_sum += *(__u32 *)(value - 4); 2: (61) r1 = *(u32 *)(r1 -4) R1 invalid (null) buffer access: off=-4, size=4 With the above commit, the error message looks like: R1_w=rdwr_buf(id=0,off=0,imm=0) R10=fp0 ; value_sum += *(__u32 *)(value - 4); 2: (61) r1 = *(u32 *)(r1 -4) R1 invalid rdwr buffer access: off=-4, size=4 Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200728221801.1090406-1-yhs@fb.com
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.