On 18/03/2025 9:19 am, Roger Pau Monne wrote: > UBSAN complains with: > > UBSAN: Undefined behaviour in arch/x86/mm/shadow/private.h:515:30 > pointer operation overflowed ffff82e000000000 to ffff82dfffffffe0 > [...] > Xen call trace: > [<ffff82d040303882>] R common/ubsan/ubsan.c#ubsan_epilogue+0xa/0xc0 > [<ffff82d040304cc3>] F > lib/xxhash64.c#__ubsan_handle_pointer_overflow+0xcb/0x100 > [<ffff82d040471c5d>] F > arch/x86/mm/shadow/guest_2.c#sh_page_fault__guest_2+0x1e350 > [<ffff82d0403b216b>] F lib/xxhash64.c#svm_vmexit_handler+0xdf3/0x2450 > [<ffff82d0402049c0>] F lib/xxhash64.c#svm_stgi_label+0x5/0x15
Something is definitely wonky in this backtrace. > > Fix by moving the call to mfn_to_page() after the check of whether the > passed gmfn is valid. This avoid the call to mfn_to_page() with an > INVALID_MFN parameter. > > While there make the page local variable const, it's not modified by the > function. > > Signed-off-by: Roger Pau Monné <roger....@citrix.com> Whatever is wonky in the backtrace isn't related to this patch, so Acked-by: Andrew Cooper <andrew.coop...@citrix.com>, but the backtrace does want fixing.
