Description
In the Linux kernel, the following vulnerability has been resolved: VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify During our test, it is found that a warning can be trigger in try_grab_folio as follow: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130 Modules linked in: CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef) RIP: 0010:try_grab_folio+0x106/0x130 Call Trace: <TASK> follow_huge_pmd+0x240/0x8e0 follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0 follow_pud_mask.constprop.0.isra.0+0x14a/0x170 follow_page_mask+0x1c2/0x1f0 __get_user_pages+0x176/0x950 __gup_longterm_locked+0x15b/0x1060 ? gup_fast+0x120/0x1f0 gup_fast_fallback+0x17e/0x230 get_user_pages_fast+0x5f/0x80 vmci_host_unlocked_ioctl+0x21c/0xf80 RIP: 0033:0x54d2cd ---[ end trace 0000000000000000 ]--- Digging into the source, context->notify_page may init by get_user_pages_fast and can be seen in vmci_ctx_unset_notify which will try to put_page. However get_user_pages_fast is not finished here and lead to following try_grab_folio warning. The race condition is shown as follow: cpu0 cpu1 vmci_host_do_set_notify vmci_host_setup_notify get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); lockless_pages_from_mm gup_pgd_range gup_huge_pmd // update &context->notify_page vmci_host_do_set_notify vmci_ctx_unset_notify notify_page = context->notify_page; if (notify_page) put_page(notify_page); // page is freed __gup_longterm_locked __get_user_pages follow_trans_huge_pmd try_grab_folio // warn here To slove this, use local variable page to make notify_page can be seen after finish get_user_pages_fast.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
a1d88436d53a75e950db15834b3d2f8c0c358fdc to < 74095bbbb19ca74a0368d857603a2438c88ca86caffecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 468aec888f838ce5174b96e0cb4396790d6f60caaffecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < b4209e4b778e4e57d0636e1c9fc07a924dbc6043affecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 58a90db70aa6616411e5f69d1982d9b1dd97d774affecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 6e3af836805ed1d7a699f76ec798626198917aa4affecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 00ddc7dad55b7bbb78df80d6e174d0c4764dea0caffecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 75b5313c80c39a26d27cbb602f968a05576c36f9affecteda1d88436d53a75e950db15834b3d2f8c0c358fdc to < 1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4affected
Linux Linux
Default version status: affected
4.0affected0 to < 4.0unaffected5.4.296 to ≤ 5.4.*unaffected5.10.240 to ≤ 5.10.*unaffected5.15.186 to ≤ 5.15.*unaffected6.1.142 to ≤ 6.1.*unaffected6.6.94 to ≤ 6.6.*unaffected6.12.34 to ≤ 6.12.*unaffected6.15.3 to ≤ 6.15.*unaffected6.16 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/74095bbbb19ca74a0368d857603a2438c88ca86c ↗
- https://git.kernel.org/stable/c/468aec888f838ce5174b96e0cb4396790d6f60ca ↗
- https://git.kernel.org/stable/c/b4209e4b778e4e57d0636e1c9fc07a924dbc6043 ↗
- https://git.kernel.org/stable/c/58a90db70aa6616411e5f69d1982d9b1dd97d774 ↗
- https://git.kernel.org/stable/c/6e3af836805ed1d7a699f76ec798626198917aa4 ↗
- https://git.kernel.org/stable/c/00ddc7dad55b7bbb78df80d6e174d0c4764dea0c ↗
- https://git.kernel.org/stable/c/75b5313c80c39a26d27cbb602f968a05576c36f9 ↗
- https://git.kernel.org/stable/c/1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4 ↗
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html ↗
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html ↗