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

net: macb: use the current queue number for stats

There's a potential mismatch between the memory reserved for statistics and the amount of memory written.

gemgetssetcount() correctly computes the number of stats based on the active queues, whereas gemgetethtoolstats() indiscriminately copies data using the maximum number of queues, and in the case the number of active queues is less than MACBMAXQUEUES, this results in a OOB write as observed in the KASAN splat.

================================================================== BUG: KASAN: vmalloc-out-of-bounds in gemgetethtool_stats+0x54/0x78 [macb] Write of size 760 at addr ffff80008080b000 by task ethtool/1027

CPU: [...] Tainted: [E]=UNSIGNEDMODULE Hardware name: raspberrypi rpi/rpi, BIOS 2025.10 10/01/2025 Call trace: showstack+0x20/0x38 (C) dumpstacklvl+0x80/0xf8 printreport+0x384/0x5e0 kasanreport+0xa0/0xf0 kasancheckrange+0xe8/0x190 __asanmemcpy+0x54/0x98 gemget_ethtoolstats+0x54/0x78 [macb 926c13f3af83b0c6fe64badb21ec87d5e93fcf65] devethtool+0x1220/0x38c0 devioctl+0x4ac/0xca8 sockdoioctl+0x170/0x1d8 sockioctl+0x484/0x5d8 _arm64sysioctl+0x12c/0x1b8 invokesyscall+0xd4/0x258 el0svccommon.constprop.0+0xb4/0x240 doel0svc+0x48/0x68 el0svc+0x40/0xf8 el0t64synchandler+0xa0/0xe8 el0t64sync+0x1b0/0x1b8

The buggy address belongs to a 1-page vmalloc region starting at 0xffff80008080b000 allocated at dev_ethtool+0x11f0/0x38c0 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff00000a333000 pfn:0xa333 flags: 0x7fffc000000000(node=0|zone=0|lastcpupid=0x1ffff) raw: 007fffc000000000 0000000000000000 dead000000000122 0000000000000000 raw: ffff00000a333000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff80008080b080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff80008080b100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

ffff80008080b180: 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffff80008080b200: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

ffff80008080b280: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

Fix it by making sure the copied size only considers the active number of queues.