CVE-2022-49625

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

sfc: fix kernel panic when creating VF

When creating VFs a kernel panic can happen when calling to efxef10tryupdatenicstatsvf.

When releasing a DMA coherent buffer, sometimes, I don't know in what specific circumstances, it has to unmap memory with vunmap. It is disallowed to do that in IRQ context or with BH disabled. Otherwise, we hit this line in vunmap, causing the crash: BUGON(ininterrupt());

This patch reenables BH to release the buffer.

Log messages when the bug is hit: kernel BUG at mm/vmalloc.c:2727! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 6 PID: 1462 Comm: NetworkManager Kdump: loaded Tainted: G I --------- --- 5.14.0-119.el9.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:vunmap+0x2e/0x30 ...skip... Call Trace: __iommudmafree+0x96/0x100 efxnicfreebuffer+0x2b/0x40 [sfc] efxef10tryupdatenicstatsvf+0x14a/0x1c0 [sfc] efxef10updatestatsvf+0x18/0x40 [sfc] efxstartall+0x15e/0x1d0 [sfc] efxnet_open+0x5a/0xe0 [sfc] __dev_open+0xe7/0x1a0 __devchangeflags+0x1d7/0x240 devchangeflags+0x21/0x60 ...skip...