[Samsung Galaxy Tab A series ROMs, Kernels, Recover] UDPSendToFailed:
Not sure if anyone else experiences freezes or random reboots since the latest update, but I'll post a temporary solution here just in case.

The issue is caused by ZRAM and it can be fixed with removing these lines from /vendor/bin/init.qcom.post_boot.sh:

function configure_zram_parameters() {
MemTotalStr=`cat /proc/meminfo | grep MemTotal`
MemTotal=${MemTotalStr:16:8}

low_ram=`getprop ro.config.low_ram`

# Zram disk - 75% for Go devices.
# For 512MB Go device, size = 384MB, set same for Non-Go.
# For 1GB Go device, size = 768MB, set same for Non-Go.
# For 2GB Go device, size = 1536MB, set same for Non-Go.
# For >2GB Non-Go devices, size = 2GB. Limit the size to 4GB.

let RamSizeGB="( $MemTotal / 1048576 ) + 1"
diskSizeUnit=M
if [ $RamSizeGB -le 2 ]; then
let zRamSizeMB="( $RamSizeGB * 1024 ) * 3 / 4"
else
let zRamSizeMB=2048
fi

# use MB avoid 32 bit overflow
if [ $zRamSizeMB -gt 4096 ]; then
let zRamSizeMB=4096
fi

# Setup zram options
echo lz4 > /sys/block/zram0/comp_algorithm
echo 4 > /sys/block/zram0/max_comp_streams
echo 0 > /proc/sys/vm/page-cluster

if [ -f /sys/block/zram0/disksize ]; then
if [ -f /sys/block/zram0/use_dedup ]; then
echo 1 > /sys/block/zram0/use_dedup
fi
echo "$zRamSizeMB""$diskSizeUnit" > /sys/block/zram0/disksize

# ZRAM may use more memory than it saves if SLAB_STORE_USER
# debug option is enabled.
if [ -e /sys/kernel/slab/zs_handle ]; then
echo 0 > /sys/kernel/slab/zs_handle/store_user
fi
if [ -e /sys/kernel/slab/zspage ]; then
echo 0 > /sys/kernel/slab/zspage/store_user
fi

mkswap /dev/block/zram0
swapon /dev/block/zram0 -p 32758
fi
}

Here is the log for those who are interested, might be caused by a kernel bug or the ZRAM settings I've used from a Xiaomi Mido tree...

<4>[ 1386.908623] [1: system_server: 1162] system_server: page allocation failure: order:0, mode:0x280020
<6>[ 1386.908696] [1: system_server: 1162] CPU: 1 PID: 1162 Comm: system_server Tainted: G WC 3.18.140Slayer #44
<6>[ 1386.908764] [1: system_server: 1162] Hardware name: Samsung Tab A2 XL WIFI EUR OPEN Rev04 (DT)
<0>[ 1386.908823] [1: system_server: 1162] Call trace:
<6>[ 1386.908868] [1: system_server: 1162] [<ffffffc00008b524>] dump_backtrace+0x0/0x108
<6>[ 1386.908921] [1: system_server: 1162] [<ffffffc00008b640>] show_stack+0x14/0x1c
<6>[ 1386.908985] [1: system_server: 1162] [<ffffffc000e569e4>] dump_stack+0x84/0xa8
<6>[ 1386.909035] [1: system_server: 1162] [<ffffffc000172520>] warn_alloc_failed+0x10c/0x124
<6>[ 1386.909092] [1: system_server: 1162] [<ffffffc0001757d4>] __alloc_pages_nodemask+0x69c/0x8b0
<6>[ 1386.909155] [1: system_server: 1162] [<ffffffc0001ae9dc>] new_slab+0x2f0/0x314
<6>[ 1386.909210] [1: system_server: 1162] [<ffffffc0001b0740>] __slab_alloc.isra.73.constprop.76+0x5ec/0x668
<6>[ 1386.909273] [1: system_server: 1162] [<ffffffc0001b083c>] kmem_cache_alloc+0x80/0x1ec
<6>[ 1386.909329] [1: system_server: 1162] [<ffffffc00027bc74>] __es_insert_extent+0x1a4/0x250
<6>[ 1386.909384] [1: system_server: 1162] [<ffffffc00027c914>] ext4_es_insert_extent+0x164/0x1c0
<6>[ 1386.909442] [1: system_server: 1162] [<ffffffc00024234c>] ext4_map_blocks+0x1c8/0x538
<6>[ 1386.909505] [1: system_server: 1162] [<ffffffc000282de8>] ext4_mpage_readpages+0x210/0x57c
<6>[ 1386.909563] [1: system_server: 1162] [<ffffffc000240978>] ext4_readpages+0x34/0x3c
<6>[ 1386.909619] [1: system_server: 1162] [<ffffffc000178d1c>] __do_page_cache_readahead+0x190/0x250
<6>[ 1386.909688] [1: system_server: 1162] [<ffffffc00016f910>] filemap_fault+0x158/0x404
<6>[ 1386.909742] [1: system_server: 1162] [<ffffffc0001947d8>] __do_fault+0x38/0x84
<6>[ 1386.909794] [1: system_server: 1162] [<ffffffc0001967e0>] do_read_fault.isra.90+0x194/0x264
<6>[ 1386.909853] [1: system_server: 1162] [<ffffffc000198300>] handle_mm_fault+0x4e8/0xaa0
<6>[ 1386.909907] [1: system_server: 1162] [<ffffffc00009efa8>] do_page_fault+0x128/0x2d8
<6>[ 1386.909959] [1: system_server: 1162] [<ffffffc000082530>] do_mem_abort+0xa8/0x10c
<6>[ 1386.910007] [1: system_server: 1162] Exception stack(0xffffffc075e7bdd0 to 0xffffffc075e7bf00)
<6>[ 1386.910066] [1: system_server: 1162] bdc0: 00000000 00000000 00000000 00000000
<6>[ 1386.910133] [1: system_server: 1162] bde0: ffffffff ffffffff 70fec360 00000000 20000000 00000000 00000020 00000000
<6>[ 1386.910214] [1: system_server: 1162] be00: 82000007 00000000 00000000 00000000 ffffffff ffffffff 72c013dc 00000000
<6>[ 1386.910280] [1: system_server: 1162] be20: 20000000 00000000 00000024 00000000 92000007 00000000 00082884 ffffffc0
<6>[ 1386.910352] [1: system_server: 1162] be40: 00000002 00000000 00002010 ffffff80 019b8000 ffffffc0 75e7bec0 ffffffc0
<6>[ 1386.910419] [1: system_server: 1162] be60: 0000200c ffffff80 13e48c10 00000000 75e7be90 ffffffc0 0008b0b4 ffffffc0
<6>[ 1386.910485] [1: system_server: 1162] be80: 75e78000 ffffffc0 00000008 00000000 720ab640 00000000 000865a4 ffffffc0
<6>[ 1386.910554] [1: system_server: 1162] bea0: 00000000 00000000 00000000 00000000 ffffffff ffffffff 00000000 00000000
<6>[ 1386.910628] [1: system_server: 1162] bec0: 70b46400 00000000 72e0ef48 00000000 00005fe4 00000000 72e0ee98 00000000
<6>[ 1386.910698] [1: system_server: 1162] bee0: 00000448 00000000 72e0f704 00000000 72e0ee50 00000000 72e0f588 00000000
<6>[ 1386.910770] [1: system_server: 1162] [<ffffffc000082608>] do_el0_ia_bp_hardening+0x74/0x7c
<6>[ 1386.910826] [1: system_server: 1162] Exception stack(0xffffffc075e7bea0 to 0xffffffc075e7bfd0)
<6>[ 1386.910894] [1: system_server: 1162] bea0: 00000000 00000000 00000000 00000000 ffffffff ffffffff 00000000 00000000
<6>[ 1386.910965] [1: system_server: 1162] bec0: 70b46400 00000000 72e0ef48 00000000 00005fe4 00000000 72e0ee98 00000000
<6>[ 1386.911039] [1: system_server: 1162] bee0: 00000448 00000000 72e0f704 00000000 72e0ee50 00000000 72e0f588 00000000
<6>[ 1386.911114] [1: system_server: 1162] bf00: 72e0ee98 00000000 720eb990 00000000 00000000 00000000 00000000 00000000
<6>[ 1386.911190] [1: system_server: 1162] bf20: 00000000 00000000 00000054 00000000 ffff0000 ffffffff 136c2458 00000000
<6>[ 1386.911259] [1: system_server: 1162] bf40: 70e56d10 00000000 70ad35e8 00000000 7bcae000 0000007d 2f287010 0000007c
<6>[ 1386.911331] [1: system_server: 1162] bf60: 00000000 00000000 00000000 00000000 73170128 00000000 00000002 00000000
<6>[ 1386.911403] [1: system_server: 1162] bf80: 72e0f588 00000000 00000002 00000000 72102c68 00000000 72102d90 00000000
<6>[ 1386.911477] [1: system_server: 1162] bfa0: 72e0ee98 00000000 720ab640 00000000 72c013e4 00000000 ebd5b060 0000007f
<6>[ 1386.911546] [1: system_server: 1162] bfc0: 70fec360 00000000 20000000 00000000
<6>[ 1386.911597] [1: system_server: 1162] Mem-Info:
<6>[ 1386.911632] [1: system_server: 1162] SystemHeap:1687652kB SystemHeapPool:0kB VmallocAPIsize:16100kB KgslSharedmem:224884kB
<6>[ 1386.911719] [1: system_server: 1162] DMA per-cpu:
<6>[ 1386.911762] [1: system_server: 1162] CPU 0: hi: 186, btch: 31 usd: 18
<6>[ 1386.911812] [1: system_server: 1162] CPU 1: hi: 186, btch: 31 usd: 24
<6>[ 1386.911865] [1: system_server: 1162] CPU 2: hi: 186, btch: 31 usd: 3
<6>[ 1386.911915] [1: system_server: 1162] CPU 3: hi: 186, btch: 31 usd: 1
<6>[ 1386.911968] [1: system_server: 1162] CPU 4: hi: 186, btch: 31 usd: 35
<6>[ 1386.912022] [1: system_server: 1162] CPU 5: hi: 186, btch: 31 usd: 11
<6>[ 1386.912073] [1: system_server: 1162] CPU 6: hi: 186, btch: 31 usd: 85
<6>[ 1386.912122] [1: system_server: 1162] CPU 7: hi: 186, btch: 31 usd: 184
<6>[ 1386.912178] [1: system_server: 1162] active_anon:1891 inactive_anon:2137 isolated_anon:0
<6>[ 1386.912178] [1: system_server: 1162] active_file:3268 inactive_file:3299 isolated_file:32
<6>[ 1386.912178] [1: system_server: 1162] unevictable:0 dirty:0 writeback:0 unstable:0
<6>[ 1386.912178] [1: system_server: 1162] free:54334 slab_reclaimable:11696 slab_unreclaimable:34013
<6>[ 1386.912178] [1: system_server: 1162] mapped:9562 shmem:142 pagetables:13976 bounce:0
<6>[ 1386.912178] [1: system_server: 1162] free_cma:53946
<6>[ 1386.912508] [1: system_server: 1162] DMA free:217088kB min:6848kB low:35112kB high:36824kB active_anon:7564kB inactive_anon:8548kB active_file:13072kB inactive_file:13196kB unevictable:0kB isolated(anon):0kB isolated(file):128kB present:3052544kB managed:2953940kB mlocked:0kB dirty:0kB writeback:0kB mapped:38248kB shmem:568kB slab_reclaimable:46784kB slab_unreclaimable:136052kB kernel_stack:27488kB pagetables:55904kB unstable:0kB bounce:0kB free_cma:215784kB writeback_tmp:0kB pages_scanned:512 all_unreclaimable? no
<6>[ 1386.912780] [1: system_server: 1162] lowmem_reserve[]: 0 0 0
<6>[ 1386.912823] [1: system_server: 1162] DMA: 6*4kB (CR) 127*8kB (UMCR) 22*16kB (MC) 4*32kB (MC) 3*64kB (C) 3*128kB (C) 3*256kB (C) 2*512kB (C) 4*1024kB (C) 4*2048kB (C) 49*4096kB (C) = 216880kB
<6>[ 1386.912952] [1: system_server: 1162] 7183 total pagecache pages
<6>[ 1386.913001] [1: system_server: 1162] 403 pages in swap cache
<6>[ 1386.913045] [1: system_server: 1162] Swap cache stats: add 1045066, delete 1044663, find 121440/378218
<6>[ 1386.913108] [1: system_server: 1162] Free swap = 1040308kB
<6>[ 1386.913149] [1: system_server: 1162] Total swap = 2097148kB
<6>[ 1386.913190] [1: system_server: 1162] 763136 pages RAM
<6>[ 1386.913228] [1: system_server: 1162] 0 pages HighMem/MovableOnly
<6>[ 1386.913271] [1: system_server: 1162] 24651 pages reserved
<4>[ 1386.913310] [1: system_server: 1162] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
<4>[ 1386.913367] [1: system_server: 1162] cache: ext4_extent_status, object size: 40, buffer size: 40, default order: 0, min order: 0
<4>[ 1386.913439] [1: system_server: 1162] node 0: slabs: 42, objs: 4284, free: 0