CVE-2021-47481

In the Linux kernel, the following vulnerability has been resolved:

RDMA/mlx5: Initialize the ODP xarray when creating an ODP MR

Normally the zero fill would hide the missing initialization, but an errant set to descsize in regcreate() causes a crash:

BUG: unable to handle page fault for address: 0000000800000000 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 890 Comm: ibwritebw Not tainted 5.15.0-rc4+ #47 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5ibderegmr+0x14/0x3b0 [mlx5ib] Code: 48 63 cd 4c 89 f7 48 89 0c 24 e8 37 30 03 e1 48 8b 0c 24 eb a0 90 0f 1f 44 00 00 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 30 <48> 8b 2f 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 31 c0 8b 87 c8 RSP: 0018:ffff88811afa3a60 EFLAGS: 00010286 RAX: 000000000000001c RBX: 0000000800000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000800000000 RBP: 0000000800000000 R08: 0000000000000000 R09: c0000000fffff7ff R10: ffff88811afa38f8 R11: ffff88811afa38f0 R12: ffffffffa02c7ac0 R13: 0000000000000000 R14: ffff88811afa3cd8 R15: ffff88810772fa00 FS: 00007f47b9080740(0000) GS:ffff88852cd40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000800000000 CR3: 000000010761e003 CR4: 0000000000370ea0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mlx5ibfreeodpmr+0x95/0xc0 [mlx5ib] mlx5ibderegmr+0x128/0x3b0 [mlx5ib] ibderegmruser+0x45/0xb0 [ibcore] ? xasload+0x8/0x80 destroyhwidruobject+0x1a/0x50 [ibuverbs] uverbsdestroyuobject+0x2f/0x150 [ibuverbs] uobjdestroy+0x3c/0x70 [ibuverbs] ibuverbscmdverbs+0x467/0xb00 [ibuverbs] ? uverbsfinalizeobject+0x60/0x60 [ibuverbs] ? ttwuqueuewakelist+0xa9/0xe0 ? ptywrite+0x85/0x90 ? filettywrite.isra.33+0x214/0x330 ? processechoes+0x60/0x60 ibuverbsioctl+0xa7/0x110 [ibuverbs] _x64sysioctl+0x10d/0x8e0 ? vfswrite+0x17f/0x260 dosyscall64+0x3c/0x80 entrySYSCALL64after_hwframe+0x44/0xae

Add the missing xarray initialization and remove the desc_size set.