CVE-2021-47090

Public Exploit

mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page()

Description

In the Linux kernel, the following vulnerability has been resolved: mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() Hulk Robot reported a panic in put_page_testzero() when testing madvise() with MADV_SOFT_OFFLINE. The BUG() is triggered when retrying get_any_page(). This is because we keep MF_COUNT_INCREASED flag in second try but the refcnt is not increased. page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:737! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 5 PID: 2135 Comm: sshd Tainted: G B 5.16.0-rc6-dirty #373 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: release_pages+0x53f/0x840 Call Trace: free_pages_and_swap_cache+0x64/0x80 tlb_flush_mmu+0x6f/0x220 unmap_page_range+0xe6c/0x12c0 unmap_single_vma+0x90/0x170 unmap_vmas+0xc4/0x180 exit_mmap+0xde/0x3a0 mmput+0xa3/0x250 do_exit+0x564/0x1470 do_group_exit+0x3b/0x100 __do_sys_exit_group+0x13/0x20 __x64_sys_exit_group+0x16/0x20 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: ---[ end trace e99579b570fe0649 ]--- RIP: 0010:release_pages+0x53f/0x840

5.5

CVSS

Severity: Medium

CVSS 3.1 •

EPSS 0.01%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/1f207076740101fed87074a6bc924dbe806f08a5	patch mailing list exploit
https://git.kernel.org/stable/c/c691e7575eff76e563b0199c23ec46bd454f43e3	patch mailing list exploit
https://git.kernel.org/stable/c/2a57d83c78f889bf3f54eede908d0643c40d5418	patch mailing list exploit

Frequently Asked Questions

What is the severity of CVE-2021-47090?: CVE-2021-47090 has been scored as a medium severity vulnerability.
How to fix CVE-2021-47090?: To fix CVE-2021-47090, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47090 being actively exploited in the wild?: It is possible that CVE-2021-47090 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47090?: CVE-2021-47090 affects Linux Linux, Linux Linux.