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246dfe3dc1
The comparison function cmp_profile_data() violates the C standard's requirements for qsort() comparison functions, which mandate symmetry and transitivity: * Symmetry: If x < y, then y > x. * Transitivity: If x < y and y < z, then x < z. When v1 and v2 are equal, the function incorrectly returns 1, breaking symmetry and transitivity. This causes undefined behavior, which can lead to memory corruption in certain versions of glibc [1]. Fix the issue by returning 0 when v1 and v2 are equal, ensuring compliance with the C standard and preventing undefined behavior. Link: https://www.qualys.com/2024/01/30/qsort.txt [1] Fixes:0f223813ed("perf ftrace: Add 'profile' command") Fixes:74ae366c37("perf ftrace profile: Add -s/--sort option") Cc: stable@vger.kernel.org Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: jserv@ccns.ncku.edu.tw Cc: chuang@cs.nycu.edu.tw Link: https://lore.kernel.org/r/20241209134226.1939163-1-visitorckw@gmail.com Signed-off-by: Namhyung Kim <namhyung@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 reStructuredText 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.