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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: CB9EA1A0007 X-Stat-Signature: gdemsftgwqsurrxbkyg7jya991aaq6xt X-Rspam-User: X-HE-Tag: 1763405905-222138 X-HE-Meta: U2FsdGVkX183ycGZB3oLkEpgIDETFt9UWrYquRC1nw4nA+Rvnhlmlu9Ig0nJO15M+6XpLBzd0Yjq4QNpd91ns37O92CVzuQKCNDGBZiH7MiAlg8MAUMLmargU9dBNZAGfpxT9+fEJBwLafFt10JZ5mh1DCfL9G5gYNppdESxcHU2oPT0oK1n6IPofrzIaw8SfX154e03aCEpLnlPZJk9igTnMz0bxdYV1snbStN/ubh8y34xTvGD+Fw0wRyAgKrCgVsqAQJVnZqSma52n5v/SnZRBJbjVHuBHs8JoeSEdXTx1G1uisSOCu0j9HVTcnX6GJpr1tWVSvDkPzAD/gU8LnfGmHPsklUQgWjAAtWYpRDANSy3ek66fIhQ2fMNUFFifSbVkyrp6gOdzsCTo5m3VoZlV6xsZq3CWvvItlShfQQjUA6nhUce0CZ6i0YtFfcsfw9Kn39tMlyb1VJAE81olb2mnZNwuhdGlBW2wGFUvyyetzpqW5wrvXE8jiK2u0WVRJWpZ41yR9wp2cDhEnm57krDHEvtF0DBOETKmktzZANt7WqpTSw3FIYOGiBX44hdcU0K8Ayn2s1BU6/F0za+U9M6Q3Sl0rVmK/E8LTg0fjLkbVAShWQv685rspAlkrwLyMKMgW4X76r1YOH6sKQOLW6oW2iJjquejdIvm8BK9mPQeUTaqn0AlN4zvZpcOSCtzkB+r07NW/jzXt0ZlbIn8pXe/opIIeZJFwezD+3AlpmeiPAnjpSRcIRx6sRe6TLdf+XM4XFF88jW53HBRqtd5yZO1KYb73u7uLaZ2LP9i0Qc2efVjCYLnwJyQlbxC5JBpfu+KJ7DbW3e07UgpOBiirwtZmNxA61utp+qI2nbAsUvlRTgMKcKENx0X6f+KRu2/AkChS3NDxOS+HaKM8HXTPpilaKD0Jt37WatYeg+6zs6mzM2z5s82Rllii0SN0UQ2uOtKdKOPU/3gNs5Ag1 JWGHxHwx qvojuAzX2jR7yUOr0+b9BQNeCrsog95xYKG/FibfykPvX5d57AzdGBP/oNgeInPmK74vgQhmv/TB8M7k92+f8/FuJNoOsvmBgIR6GE4TrbnbcyqpglyeojIrI19rjUq4kIbNlxE8KTTqepzeSz+M4T4okkbMeqF2s8yFfRKbTl+cGhsaLnKMNYshWYGc95ci1bj3VF/5zvSG59shhG0ftEG/n9Mck1ahD8tduUDNca3VGcgkJGcp9e0H059nSdNlwrwLTUiLBmqtUJGG+g8QhmhqayDKKaYIERneR4LejnrFFmaIkaI5ihDIu2u05psd4ztCXhNDgTmaQ8TRje3e8Km1MiEIHe0hBP7Zjcjj+rDSlJZTT751dUSbuprN7KRiLmqS3kunp4rBqwaDYjPN5wrteeUrrGwhh0lTh X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-11-10 at 17:24:38 +0100, Alexander Potapenko wrote: >On Wed, Oct 29, 2025 at 9:07=E2=80=AFPM Maciej Wieczor-Retman > wrote: >> >> From: Maciej Wieczor-Retman >> >> Calculating page offset returns a pointer without a tag. When comparing >> the calculated offset to a tagged page pointer an error is raised >> because they are not equal. >> >> Change pointer comparisons to physical address comparisons as to avoid >> issues with tagged pointers that pointer arithmetic would create. Open >> code pte_offset_kernel(), pmd_offset(), pud_offset() and p4d_offset(). >> Because one parameter is always zero and the rest of the function >> insides are enclosed inside __va(), removing that layer lowers the >> complexity of final assembly. >> >> Signed-off-by: Maciej Wieczor-Retman >> --- >> Changelog v2: >> - Open code *_offset() to avoid it's internal __va(). >> >> arch/x86/mm/init_64.c | 11 +++++++---- >> 1 file changed, 7 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c >> index 0e4270e20fad..2d79fc0cf391 100644 >> --- a/arch/x86/mm/init_64.c >> +++ b/arch/x86/mm/init_64.c >> @@ -269,7 +269,10 @@ static p4d_t *fill_p4d(pgd_t *pgd, unsigned long va= ddr) >> if (pgd_none(*pgd)) { >> p4d_t *p4d =3D (p4d_t *)spp_getpage(); >> pgd_populate(&init_mm, pgd, p4d); >> - if (p4d !=3D p4d_offset(pgd, 0)) >> + >> + if (__pa(p4d) !=3D (pgtable_l5_enabled() ? >> + __pa(pgd) : >> + (unsigned long)pgd_val(*pgd) & PTE_PFN= _MASK)) > >Did you test with both 4- and 5-level paging? >If I understand correctly, p4d and pgd are supposed to be the same >under !pgtable_l5_enabled(). Yes, I do test on both paging modes. Looking at p4d_offset() I think I got the cases reversed somehow. Weird that it didn't raise any issues afterwards. Thanks for pointing it out :)