# CVE-2025-39731: f2fs: vm_unmap_ram() may be called from an invalid context

CVE-2025-39731 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-39731, released September 7, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-39731
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 7, 2025
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39731

## Description

In the Linux kernel, the following vulnerability has been resolved:  f2fs: vm_unmap_ram() may be called from an invalid context  When testing F2FS with xfstests using UFS backed virtual disks the kernel complains sometimes that f2fs_release_decomp_mem() calls vm_unmap_ram() from an invalid context. Example trace from f2fs/007 test:  f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007 [   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978 [   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd [   11.475357] preempt_count: 1, expected: 0 [   11.476970] RCU nest depth: 0, expected: 0 [   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none) [   11.478535] Tainted: [W]=WARN [   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [   11.478537] Call Trace: [   11.478543]  <TASK> [   11.478545]  dump_stack_lvl+0x4e/0x70 [   11.478554]  __might_resched.cold+0xaf/0xbe [   11.478557]  vm_unmap_ram+0x21/0xb0 [   11.478560]  f2fs_release_decomp_mem+0x59/0x80 [   11.478563]  f2fs_free_dic+0x18/0x1a0 [   11.478565]  f2fs_finish_read_bio+0xd7/0x290 [   11.478570]  blk_update_request+0xec/0x3b0 [   11.478574]  ? sbitmap_queue_clear+0x3b/0x60 [   11.478576]  scsi_end_request+0x27/0x1a0 [   11.478582]  scsi_io_completion+0x40/0x300 [   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0 [   11.478588]  ufshcd_sl_intr+0x194/0x1f0 [   11.478592]  ufshcd_threaded_intr+0x68/0xb0 [   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10 [   11.478599]  irq_thread_fn+0x20/0x60 [   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10 [   11.478603]  irq_thread+0xb9/0x180 [   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10 [   11.478607]  ? __pfx_irq_thread+0x10/0x10 [   11.478609]  kthread+0x10a/0x230 [   11.478614]  ? __pfx_kthread+0x10/0x10 [   11.478615]  ret_from_fork+0x7e/0xd0 [   11.478619]  ? __pfx_kthread+0x10/0x10 [   11.478621]  ret_from_fork_asm+0x1a/0x30 [   11.478623]  </TASK>  This patch modifies in_task() check inside f2fs_read_end_io() to also check if interrupts are disabled. This ensures that pages are unmapped asynchronously in an interrupt handler.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.148-1 | [DEBIAN-CVE-2025-39731](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39731.md) | Sep 7, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.12.43-1 | [DEBIAN-CVE-2025-39731](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39731.md) | Sep 7, 2025 |
| Linux | linux Debian 14 | 6.16.3-1 | [DEBIAN-CVE-2025-39731](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39731.md) | Sep 7, 2025 |

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