CVE-2025-40196

In the Linux kernel, the following vulnerability has been resolved:

fs: quota: create dedicated workqueue for quota_release_work

There is a kernel panic due to WARN_ONCE when panic_on_warn is set.

This issue occurs when writeback is triggered due to sync call for an

opened file(ie, writeback reason is WB_REASON_SYNC). When f2fs balance

is needed at sync path, flush for quota_release_work is triggered.

By default quota_release_work is queued to "events_unbound" queue which

does not have WQ_MEM_RECLAIM flag. During f2fs balance "writeback"

workqueue tries to flush quota_release_work causing kernel panic due to

MEM_RECLAIM flag mismatch errors.

This patch creates dedicated workqueue with WQ_MEM_RECLAIM flag

for work quota_release_work.

------------[ cut here ]------------

WARNING: CPU: 4 PID: 14867 at kernel/workqueue.c:3721 check_flush_dependency+0x13c/0x148

Call trace:

check_flush_dependency+0x13c/0x148

__flush_work+0xd0/0x398

flush_delayed_work+0x44/0x5c

dquot_writeback_dquots+0x54/0x318

f2fs_do_quota_sync+0xb8/0x1a8

f2fs_write_checkpoint+0x3cc/0x99c

f2fs_gc+0x190/0x750

f2fs_balance_fs+0x110/0x168

f2fs_write_single_data_page+0x474/0x7dc

f2fs_write_data_pages+0x7d0/0xd0c

do_writepages+0xe0/0x2f4

__writeback_single_inode+0x44/0x4ac

writeback_sb_inodes+0x30c/0x538

wb_writeback+0xf4/0x440

wb_workfn+0x128/0x5d4

process_scheduled_works+0x1c4/0x45c

worker_thread+0x32c/0x3e8

kthread+0x11c/0x1b0

ret_from_fork+0x10/0x20

Kernel panic - not syncing: kernel: panic_on_warn set ...