In the Linux kernel, the following vulnerability has been resolved:
mm/gup: fix guppudrange() for dax
For dax pud, pudhuge() returns true on x86. So the function works as long as hugetlb is configured. However, dax doesn't depend on hugetlb. Commit 414fd080d125 ("mm/gup: fix guppmd_range() for dax") fixed devmap-backed huge PMDs, but missed devmap-backed huge PUDs. Fix this as well.
This fixes the below kernel panic:
general protection fault, probably for non-canonical address 0x69e7c000cc478: 0000 [#1] SMP < snip > Call Trace: <TASK> getuserpagesfast+0x1f/0x40 iovitergetpages+0xc6/0x3b0 ? mempoolalloc+0x5d/0x170 bioiovitergetpages+0x82/0x4e0 ? bvecalloc+0x91/0xc0 ? bioallocbioset+0x19a/0x2a0 blkdevdirectIO+0x282/0x480 ? _iocompleterwcommon+0xc0/0xc0 ? filemaprangehaspage+0x82/0xc0 genericfiledirectwrite+0x9d/0x1a0 ? inodeupdatetime+0x24/0x30 _genericfilewriteiter+0xbd/0x1e0 blkdevwriteiter+0xb4/0x150 ? ioimportiovec+0x8d/0x340 iowrite+0xf9/0x300 ioissuesqe+0x3c3/0x1d30 ? sysvecrescheduleipi+0x6c/0x80 _ioqueuesqe+0x33/0x240 ? fget+0x76/0xa0 iosubmitsqes+0xe6a/0x18d0 ? _fgetlight+0xd1/0x100 _x64sysiouringenter+0x199/0x880 ? _contexttrackingenter+0x1f/0x70 ? irqentryexittousermode+0x24/0x30 ? irqentryexit+0x1d/0x30 ? _contexttrackingexit+0xe/0x70 dosyscall64+0x3b/0x90 entrySYSCALL64afterhwframe+0x61/0xcb RIP: 0033:0x7fc97c11a7be < snip > </TASK> ---[ end trace 48b2e0e67debcaeb ]--- RIP: 0010:internalgetuserpagesfast+0x340/0x990 < snip > Kernel panic - not syncing: Fatal exception Kernel Offset: disabled