Linux kernel: F2FS GC_Merge path deadlock mitigated
CVE-2026-68459 Published on August 15, 2026
f2fs: fix potential deadlock in gc_merge path of f2fs_balance_fs()
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix potential deadlock in gc_merge path of f2fs_balance_fs()
When we mount device w/ gc_merge mount option, we may suffer below
potential deadlock:
Kworker GC trehad Truncator
- f2fs_write_cache_pages
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- folio_start_writeback --- set writeback flag on folio
- f2fs_outplace_write_data
: cached folio in internal bio cache
- f2fs_balance_fs
- wake_up(gc_thread)
: wake up gc thread to run foreground GC
- finish_wait(fggc_wq)
: wait on the waitqueue --- wait on GC thread to finish the work
- truncate_inode_pages_range
- __filemap_get_folio(, FGP_LOCK) --- lock folio
- truncate_inode_partial_folio
- folio_wait_writeback --- wait on writeback being cleared
- do_garbage_collect
- move_data_page
- f2fs_get_lock_data_folio
- lock on folio --- blocked on folio's lock
In order to avoid such deadlock, let's call below functions to commit
cached bios in GC_MERGE path of f2fs_balance_fs() as the same as we did
in NOGC_MERGE path.
- f2fs_submit_merged_write(sbi, DATA);
- f2fs_submit_all_merged_ipu_writes(sbi);
Products Associated with CVE-2026-68459
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Affected Versions
Linux:- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below 8071500a8124e5a6d47d901a8d5ffd91743107a1 is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below eb02f218aacb36365e0ca2339cbae81fb05d31a5 is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below 1436031b33fa23ab1ce7df5bc5500093413e8acf is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below b885c7783c19c36c7bf899492a0bffcd68afa8c7 is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below 89479a27fa4e1e11f378b3724944eabceb84f114 is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below aa807064473abd6f2cafe419fb77ea402d3e3104 is affected.
- Version 351df4b201157351c7d26bf12c3eeb9dbce98854 and below 8b4468ec023d0d1b4669dfb867588997cc03a06b is affected.
- Version 3.8 is affected.
- Before 3.8 is unaffected.
- Version 5.15.212, <= 5.15.* is unaffected.
- Version 6.1.178, <= 6.1.* is unaffected.
- Version 6.6.145, <= 6.6.* is unaffected.
- Version 6.12.96, <= 6.12.* is unaffected.
- Version 6.18.39, <= 6.18.* is unaffected.
- Version 7.1.5, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.