4f81c16f50
When open code iterators, bpf_loop or may_goto are used the following two states are equivalent and safe to prune the search: cur state: fp-8_w=scalar(id=3,smin=umin=smin32=umin32=2,smax=umax=smax32=umax32=11,var_off=(0x0; 0xf)) old state: fp-8_rw=scalar(id=2,smin=umin=smin32=umin32=1,smax=umax=smax32=umax32=11,var_off=(0x0; 0xf)) In other words "exact" state match should ignore liveness and precision marks, since open coded iterator logic didn't complete their propagation, reg_old->type == NOT_INIT && reg_cur->type != NOT_INIT is also not safe to prune while looping, but range_within logic that applies to scalars, ptr_to_mem, map_value, pkt_ptr is safe to rely on. Avoid doing such comparison when regular infinite loop detection logic is used, otherwise bounded loop logic will declare such "infinite loop" as false positive. Such example is in progs/verifier_loops1.c not_an_inifinite_loop(). Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Tested-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240306031929.42666-3-alexei.starovoitov@gmail.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.