Bugzilla – Bug 1220948
VUL-0: CVE-2021-47090: kernel: mm/hwpoison: madvise() with MADV_SOFT_OFFLINE may trigger BUG() assertion
Last modified: 2024-05-31 13:10:49 UTC
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 References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47090 https://git.kernel.org/stable/c/c691e7575eff76e563b0199c23ec46bd454f43e3 https://www.cve.org/CVERecord?id=CVE-2021-47090 https://git.kernel.org/stable/c/1f207076740101fed87074a6bc924dbe806f08a5 https://git.kernel.org/stable/c/2a57d83c78f889bf3f54eede908d0643c40d5418
Affects cve/linux-5.14. cve/linux-5.3 and older are not affected. SLE15-SP6, stable and master are already fixed.
Michal, this is in mm. Please, reassign it to Vlasta if it is in his area.
This CVE doesn't make any sense IMHO. This is CAP_SYSADMIN only interface and it can be harmful by other means. I will try to dispute it. It doesn't affect our kernels because we do not compile with CONFIG_DEBUG_VM=y.
All done, closing.