CVE-2025-39731

  • Published: 2025-09-07T16:15:48.547

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]
[ 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]

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.

Related CVE by CWE

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How to fix CVE-2025-39731

CVE-2025-39731 is a unknown severity vulnerability affecting the affected product.

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 [ […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Sep 07, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.