Describe CVE-2021-47212.
What is CVE-2021-47212?
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Update error handler for UCTX and UMEM

In the fast unload flow, the device state is set to internal error,
which indicates that the driver started the destroy process.
In this case, when a destroy command is being executed, it should return
MLX5_CMD_STAT_OK.
Fix MLX5_CMD_OP_DESTROY_UCTX and MLX5_CMD_OP_DESTROY_UMEM to return OK
instead of EIO.

This fixes a call trace in the umem release process -
[ 2633.536695] Call Trace:
[ 2633.537518]  ib_uverbs_remove_one+0xc3/0x140 [ib_uverbs]
[ 2633.538596]  remove_client_context+0x8b/0xd0 [ib_core]
[ 2633.539641]  disable_device+0x8c/0x130 [ib_core]
[ 2633.540615]  __ib_unregister_device+0x35/0xa0 [ib_core]
[ 2633.541640]  ib_unregister_device+0x21/0x30 [ib_core]
[ 2633.542663]  __mlx5_ib_remove+0x38/0x90 [mlx5_ib]
[ 2633.543640]  auxiliary_bus_remove+0x1e/0x30 [auxiliary]
[ 2633.544661]  device_release_driver_internal+0x103/0x1f0
[ 2633.545679]  bus_remove_device+0xf7/0x170
[ 2633.546640]  device_del+0x181/0x410
[ 2633.547606]  mlx5_rescan_drivers_locked.part.10+0x63/0x160 [mlx5_core]
[ 2633.548777]  mlx5_unregister_device+0x27/0x40 [mlx5_core]
[ 2633.549841]  mlx5_uninit_one+0x21/0xc0 [mlx5_core]
[ 2633.550864]  remove_one+0x69/0xe0 [mlx5_core]
[ 2633.551819]  pci_device_remove+0x3b/0xc0
[ 2633.552731]  device_release_driver_internal+0x103/0x1f0
[ 2633.553746]  unbind_store+0xf6/0x130
[ 2633.554657]  kernfs_fop_write+0x116/0x190
[ 2633.555567]  vfs_write+0xa5/0x1a0
[ 2633.556407]  ksys_write+0x4f/0xb0
[ 2633.557233]  do_syscall_64+0x5b/0x1a0
[ 2633.558071]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[ 2633.559018] RIP: 0033:0x7f9977132648
[ 2633.559821] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 55 6f 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
[ 2633.562332] RSP: 002b:00007fffb1a83888 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 2633.563472] RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f9977132648
[ 2633.564541] RDX: 000000000000000c RSI: 000055b90546e230 RDI: 0000000000000001
[ 2633.565596] RBP: 000055b90546e230 R08: 00007f9977406860 R09: 00007f9977a54740
[ 2633.566653] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f99774056e0
[ 2633.567692] R13: 000000000000000c R14: 00007f9977400880 R15: 000000000000000c
[ 2633.568725] ---[ end trace 10b4fe52945e544d ]---.