c8f6d28582
commit 2a0992829ea3864939d917a5c7b48be6629c6217 upstream.
It turns out that .branches > 0 in is_state_visited() is not a
sufficient condition to identify if two verifier states form a loop
when iterators convergence is computed. This commit adds logic to
distinguish situations like below:
(I) initial (II) initial
| |
V V
.---------> hdr ..
| | |
| V V
| .------... .------..
| | | | |
| V V V V
| ... ... .-> hdr ..
| | | | | |
| V V | V V
| succ <- cur | succ <- cur
| | | |
| V | V
| ... | ...
| | | |
'----' '----'
For both (I) and (II) successor 'succ' of the current state 'cur' was
previously explored and has branches count at 0. However, loop entry
'hdr' corresponding to 'succ' might be a part of current DFS path.
If that is the case 'succ' and 'cur' are members of the same loop
and have to be compared exactly.
Co-developed-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Co-developed-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Reviewed-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231024000917.12153-6-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.