{"id":"DEBIAN-CVE-2021-47637","details":"In the Linux kernel, the following vulnerability has been resolved:  ubifs: Fix deadlock in concurrent rename whiteout and inode writeback  Following hung tasks: [   77.028764] task:kworker/u8:4    state:D stack:    0 pid:  132 [   77.028820] Call Trace: [   77.029027]  schedule+0x8c/0x1b0 [   77.029067]  mutex_lock+0x50/0x60 [   77.029074]  ubifs_write_inode+0x68/0x1f0 [ubifs] [   77.029117]  __writeback_single_inode+0x43c/0x570 [   77.029128]  writeback_sb_inodes+0x259/0x740 [   77.029148]  wb_writeback+0x107/0x4d0 [   77.029163]  wb_workfn+0x162/0x7b0  [   92.390442] task:aa              state:D stack:    0 pid: 1506 [   92.390448] Call Trace: [   92.390458]  schedule+0x8c/0x1b0 [   92.390461]  wb_wait_for_completion+0x82/0xd0 [   92.390469]  __writeback_inodes_sb_nr+0xb2/0x110 [   92.390472]  writeback_inodes_sb_nr+0x14/0x20 [   92.390476]  ubifs_budget_space+0x705/0xdd0 [ubifs] [   92.390503]  do_rename.cold+0x7f/0x187 [ubifs] [   92.390549]  ubifs_rename+0x8b/0x180 [ubifs] [   92.390571]  vfs_rename+0xdb2/0x1170 [   92.390580]  do_renameat2+0x554/0x770  , are caused by concurrent rename whiteout and inode writeback processes: \trename_whiteout(Thread 1)\t        wb_workfn(Thread2) ubifs_rename   do_rename     lock_4_inodes (Hold ui_mutex)     ubifs_budget_space       make_free_space         shrink_liability \t  __writeback_inodes_sb_nr \t    bdi_split_work_to_wbs (Queue new wb work) \t\t\t\t\t      wb_do_writeback(wb work) \t\t\t\t\t\t__writeback_single_inode \t\t\t\t\t          ubifs_write_inode \t\t\t\t\t            LOCK(ui_mutex) \t\t\t\t\t\t\t   ↑ \t      wb_wait_for_completion (Wait wb work) \u003c-- deadlock!  Reproducer (Detail program in [Link]):   1. SYS_renameat2(\"/mp/dir/file\", \"/mp/dir/whiteout\", RENAME_WHITEOUT)   2. Consume out of space before kernel(mdelay) doing budget for whiteout  Fix it by doing whiteout space budget before locking ubifs inodes. BTW, it also fixes wrong goto tag 'out_release' in whiteout budget error handling path(It should at least recover dir i_size and unlock 4 ubifs inodes).","modified":"2026-09-15T09:02:36.144034333Z","published":"2025-02-26T06:37:05.477Z","upstream":["CVE-2021-47637"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-47637"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.17.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47637.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.17.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47637.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.17.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47637.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}