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charset="UTF-8" X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B9A94100011 X-Rspam-User: X-Stat-Signature: oo8wb1tasa7gt9hcnepnk3i1ok4469ak X-HE-Tag: 1676561717-332435 X-HE-Meta: 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 JlmOT/nU 9r7wYrOLuSQF9bicPowQUM3HNXS70uoTKnucaAjlpV1fH3aOI2+e1EQ0uCGqlZi4cBFqkKKuicKpOgfS0qmiEqMVUAQpJx1OjiRiNgAHcAj69eD8EywEIIaZg/8BshV3N/bIkp/hybzcVgpc3+QE4atjL/INhiDhTxC11DC9b2p7kFDNgC+oZPhdmm4pGN2D+DZp369t5ZYdbdMsNaMXuTN1BOBs8jhYk92zp4s5MvX7nMjen7xSvPvEX3qKix6XvRuxUv5Lg++DFMrfeqd+l5Mqw7G20UNScexgEVyQAtYkk4NsqbW2+c9D28iShQQvjDumErRtsxrTSOos/fFngGVOgTEGkH/T6VtV7gMTFtu5pYWkQlqe65mpdAdBJBOwxVlhP7d4JtSyXE3RYN1+m/+EZcQ== 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: On Thu, 16 Feb 2023 at 07:06, Mike Kravetz wrote: > > Users can specify the hugetlb page size in the mmap, shmget and > memfd_create system calls. This is done by using 6 bits within the > flags argument to encode the base-2 logarithm of the desired page size. > The routine hstate_sizelog() uses the log2 value to find the > corresponding hugetlb hstate structure. Converting the log2 value > (page_size_log) to potential hugetlb page size is the simple statement: > > 1UL << page_size_log > > Because only 6 bits are used for page_size_log, the left shift can not > be greater than 63. This is fine on 64 bit architectures where a long > is 64 bits. However, if a value greater than 31 is passed on a 32 bit > architecture (where long is 32 bits) the shift will result in undefined > behavior. This was generally not an issue as the result of the > undefined shift had to exactly match hugetlb page size to proceed. > > Recent improvements in runtime checking have resulted in this undefined > behavior throwing errors such as reported below. > > Fix by comparing page_size_log to BITS_PER_LONG before doing shift. This proposed fix tested and confirmed that reported issues were fixed. > > Reported-by: Naresh Kamboju > Link: https://lore.kernel.org/lkml/CA+G9fYuei_Tr-vN9GS7SfFyU1y9hNysnf=PB7kT0=yv4MiPgVg@mail.gmail.com/ > Fixes: 42d7395feb56 ("mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB") > Cc: > Signed-off-by: Mike Kravetz Tested-by: Linux Kernel Functional Testing Tested-by: Naresh Kamboju > --- > include/linux/hugetlb.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index df6dd624ccfe..8b45720f9475 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -781,7 +781,10 @@ static inline struct hstate *hstate_sizelog(int page_size_log) > if (!page_size_log) > return &default_hstate; > > - return size_to_hstate(1UL << page_size_log); > + if (page_size_log < BITS_PER_LONG) > + return size_to_hstate(1UL << page_size_log); > + > + return NULL; > } > > static inline struct hstate *hstate_vma(struct vm_area_struct *vma) > -- > 2.39.1 -- Linaro LKFT https://lkft.linaro.org