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CVE-2025-37834
mm/vmscan: don't try to reclaim hwpoison folio
Published 2025-05-08 (17 months ago) by the Linux kernel CNA. Subsystem mm. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2025-37834 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.12.27-1 | Update the kernel and reboot. Fixed in 6.12.27-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 6.12.27-1 | Update the kernel and reboot. Fixed in 6.12.27-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 6.12.27-1 | Update the kernel and reboot. Fixed in 6.12.27-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Syzkaller reports a bug as follows: Injecting memory failure for pfn 0x18b00e at process virtual address 0x20ffd000 Memory failure: 0x18b00e: dirty swapcache page still referenced by 2 users Memory failure: 0x18b00e: recovery action for dirty swapcache page: Failed page: refcount:2 mapcount:0 mapping:0000000000000000 index:0x20ffd pfn:0x18b00e memcg:ffff0000dd6d9000 anon flags: 0x5ffffe00482011(locked|dirty|arch_1|swapbacked|hwpoison|node=0|zone=2|lastcpupid=0xfffff) raw: 005ffffe00482011 dead000000000100 dead000000000122 ffff0000e232a7c9 raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff0000dd6d9000 page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio)) ------------[ cut here ]------------ kernel BUG at mm/swap_state.c:184! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Modules linked in: CPU: 0 PID: 60 Comm: kswapd0 Not tainted 6.6.0-gcb097e7de84e #3 Hardware name: linux,dummy-virt (DT) pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : add_to_swap+0xbc/0x158 lr : add_to_swap+0xbc/0x158 sp : ffff800087f37340 x29: ffff800087f37340 x28: fffffc00052c0380 x27: ffff800087f37780 x26: ffff800087f37490 x25: ffff800087f37c78 x24: ffff800087f377a0 x23: ffff800087f37c50 x22: 0000000000000000 x21: fffffc00052c03b4 x20: 0000000000000000 x19: fffffc00052c0380 x18: 0000000000000000 x17: 296f696c6f662865 x16: 7461646f7470755f x15: 747365745f6f696c x14: 6f6621284f494c4f x13: 0000000000000001 x12: ffff600036d8b97b x11: 1fffe00036d8b97a x10: ffff600036d8b97a x9 : dfff800000000000 x8 : 00009fffc9274686 x7 : ffff0001b6c5cbd3 x6 : 0000000000000001 x5 : ffff0000c25896c0 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : ffff0000c25896c0 x0 : 0000000000000000 Call trace: add_to_swap+0xbc/0x158 shrink_folio_list+0x12ac/0x2648 shrink_inactive_list+0x318/0x948 shrink_lruvec+0x450/0x720 shrink_node_memcgs+0x280/0x4a8 shrink_node+0x128/0x978 balance_pgdat+0x4f0/0xb20 kswapd+0x228/0x438 kthread+0x214/0x230 ret_from_fork+0x10/0x20 I can reproduce this issue with the following steps: 1) When a dirty swapcache page is isolated by reclaim process and the page isn't locked, inject memory failure for the page. me_swapcache_dirty() clears uptodate flag and tries to delete from lru, but fails. Reclaim process will put the hwpoisoned page back to lru. 2) The process that maps the hwpoisoned page exits, the page is deleted the page will never be freed and will be in the lru forever. 3) If we trigger a reclaim again and tries to reclaim the page, add_to_swap() will trigger VM_BUG_ON_FOLIO due to the uptodate flag is cleared. To fix it, skip the hwpoisoned page in shrink_folio_list(). Besides, the hwpoison folio may not be unmapped by hwpoison_user_mappings() yet, unmap it in shrink_folio_list(), otherwise the folio will fail to be unmaped by hwpoison_user_mappings() since the folio isn't in lru list.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
mm/vmscan.c
- What this is
- MEMORY MANAGEMENT - MGLRU (MULTI-GEN LRU)MAINTAINERS section matched on mm/vmscan.c · linux-mm@kvack.org · Maintained
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS Debian linux-config packages
Signals
- Published
- 2025-05-08 (17 months ago)source
- CVSS
- no vector published, unrated
- Attack vector
- not published
- EPSS
- 0.19%, higher than 7.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- mm
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.32 | 6.12.26 | 1c9798bf8145 |
| 2.6.32 | 6.14.5 | 912e9f0300c3 |
| 2.6.32 | 6.15 | 1b0449544c64 |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2025-37834, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.