In the Linux kernel, the following vulnerability has been resolved: powerpc/fixmap: Fix VM debug warning on unmap Unmapping a fixmap entry is done by calling _setfixmap() with FIXMAPPAGECLEAR as flags. Today, powerpc _setfixmap() calls mapkernelpage(). mapkernelpage() is not happy when called a second time for the same page. WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/pgtable.c:194 setpteat+0xc/0x1e8 CPU: 0 PID: 1 Comm: swapper Not tainted 5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty #682 NIP: c0017cd4 LR: c00187f0 CTR: 00000010 REGS: e1011d50 TRAP: 0700 Not tainted (5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty) MSR: 00029032 <EE,ME,IR,DR,RI> CR: 42000208 XER: 00000000 GPR00: c0165fec e1011e10 c14c0000 c0ee2550 ff800000 c0f3d000 00000000 c001686c GPR08: 00001000 b00045a9 00000001 c0f58460 c0f50000 00000000 c0007e10 00000000 GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 GPR24: 00000000 00000000 c0ee2550 00000000 c0f57000 00000ff8 00000000 ff800000 NIP [c0017cd4] setpteat+0xc/0x1e8 LR [c00187f0] mapkernelpage+0x9c/0x100 Call Trace: [e1011e10] [c0736c68] vsnprintf+0x358/0x6c8 (unreliable) [e1011e30] [c0165fec] _setfixmap+0x30/0x44 [e1011e40] [c0c13bdc] earlyiounmap+0x11c/0x170 [e1011e70] [c0c06cb0] ioremaplegacyserialconsole+0x88/0xc0 [e1011e90] [c0c03634] dooneinitcall+0x80/0x178 [e1011ef0] [c0c0385c] kernelinitfreeable+0xb4/0x250 [e1011f20] [c0007e34] kernelinit+0x24/0x140 [e1011f30] [c0016268] retfromkernelthread+0x5c/0x64 Instruction dump: 7fe3fb78 48019689 80010014 7c630034 83e1000c 5463d97e 7c0803a6 38210010 4e800020 81250000 712a0001 41820008 <0fe00000> 9421ffe0 93e1001c 48000030 Implement unmapkernelpage() which clears an existing pte.
{ "availability": "No subscription required", "binaries": [ { "binary_name": "linux-buildinfo-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-cloud-tools-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-headers-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-image-unsigned-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-image-unsigned-5.15.0-1008-intel-iotg-dbgsym", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-cloud-tools-5.15.0-1008", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-cloud-tools-common", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-headers-5.15.0-1008", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-tools-5.15.0-1008", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-tools-common", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-intel-iotg-5.15-tools-host", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-modules-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-modules-extra-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" }, { "binary_name": "linux-tools-5.15.0-1008-intel-iotg", "binary_version": "5.15.0-1008.11~20.04.1" } ] }