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List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/3] PCI: Relaxed tail alignment should never increase min_align To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , linux-pci@vger.kernel.org, Bjorn Helgaas Cc: stable@vger.kernel.org, LKML , kernel-janitors@vger.kernel.org, =?UTF-8?Q?Christian_K=C3=B6nig?= , D Scott Phillips , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Rio Liu , Tudor Ambarus References: <20250630142641.3516-2-ilpo.jarvinen@linux.intel.com> <8e9936e5-d720-4ded-8961-b9475aeb2ac7@web.de> <21e11870-f125-e9e7-04f3-ade94d6be6b1@linux.intel.com> Content-Language: en-GB, de-DE From: Markus Elfring In-Reply-To: <21e11870-f125-e9e7-04f3-ade94d6be6b1@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:8oLA+mmkBygwao9p72ovdCNmXmySN/qmjBz+S0JFUrfxCYt7P0L SLj59PjlMgn2lXSeSPZBYarYEVpxN+GIz3FuF1znX13ezZgXmQ0crFXfX/mWV0jg1yvmVOz 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22OKbHC8rIMy+A7hexi7R4I5P8UcO7/xWoekM0wKb31N8YZOM0PjS4Zk+JuL/aKLBw8kkxI6J 4k590zmXMVFsCaxd94/ti8ryZALsiBdK4si8SzjceK3w4cKB3yighnsj6j/7oQHBgQ3Y6CGxZ ednv4Yo34z2lmR2/E5uXYQrhLAAl6IMjFLIgrKG8A9HidLhIL0G8ZuFag1cstYu1x8jxMzNyH 9tpBJ7BcO31tJnQjH1R3DlxE3horqYDZV+AXncVs2xQVhw8TJnyxYJ90Etsh9NOKmJoCWrg= >> =E2=80=A6 >> +++ b/drivers/pci/setup-bus.c >> =E2=80=A6 >> @@ -1261,8 +1263,9 @@ static int pbus_size_mem(struct pci_bus *bus, uns= igned long mask, >> if (bus->self && size1 && >> !pbus_upstream_space_available(bus, mask | IORESOURCE_PREFETCH, = type, >> size1, add_align)) { >> - min_align =3D 1ULL << (max_order + __ffs(SZ_1M)); >> - min_align =3D max(min_align, win_align); >> + relaxed_align =3D 1ULL << (max_order + __ffs(SZ_1M)); >> + relaxed_align =3D max(min_align, win_align); >> =E2=80=A6 >> >> I wonder why a variable content would be overwritten here >> without using the previous value. >> https://cwe.mitre.org/data/definitions/563.html =E2=80=A6> This looks a very good catch. I think it too should have been: >=20 > relaxed_align =3D max(relaxed_align, win_align); >=20 > ...like in the other case. Did any known source code analysis tools point such a questionable impleme= ntation detail out for further development considerations? Regards, Markus