1.7 KiB
CVE-2025-21908
Description
In the Linux kernel, the following vulnerability has been resolved:NFS: fix nfs_release_folio() to not deadlock via kcompactd writebackAdd PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it sonfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.Otherwise NFS can deadlock waiting for kcompactd enduced writeback whichrecurses back to NFS (which triggers writeback to NFSD via NFS loopbackmount on the same host, NFSD blocks waiting for XFS's call to__filemap_get_folio):6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.{---[58] "kcompactd0"[<0>] folio_wait_bit+0xe8/0x200[<0>] folio_wait_writeback+0x2b/0x80[<0>] nfs_wb_folio+0x80/0x1b0 [nfs][<0>] nfs_release_folio+0x68/0x130 [nfs][<0>] split_huge_page_to_list_to_order+0x362/0x840[<0>] migrate_pages_batch+0x43d/0xb90[<0>] migrate_pages_sync+0x9a/0x240[<0>] migrate_pages+0x93c/0x9f0[<0>] compact_zone+0x8e2/0x1030[<0>] compact_node+0xdb/0x120[<0>] kcompactd+0x121/0x2e0[<0>] kthread+0xcf/0x100[<0>] ret_from_fork+0x31/0x40[<0>] ret_from_fork_asm+0x1a/0x30---}[akpm@linux-foundation.org: fix build]
POC
Reference
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