{"id":"CVE-2025-39866","summary":"fs: writeback: fix use-after-free in __mark_inode_dirty()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: writeback: fix use-after-free in __mark_inode_dirty()\n\nAn use-after-free issue occurred when __mark_inode_dirty() get the\nbdi_writeback that was in the progress of switching.\n\nCPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1\n......\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : __mark_inode_dirty+0x124/0x418\nlr : __mark_inode_dirty+0x118/0x418\nsp : ffffffc08c9dbbc0\n........\nCall trace:\n __mark_inode_dirty+0x124/0x418\n generic_update_time+0x4c/0x60\n file_modified+0xcc/0xd0\n ext4_buffered_write_iter+0x58/0x124\n ext4_file_write_iter+0x54/0x704\n vfs_write+0x1c0/0x308\n ksys_write+0x74/0x10c\n __arm64_sys_write+0x1c/0x28\n invoke_syscall+0x48/0x114\n el0_svc_common.constprop.0+0xc0/0xe0\n do_el0_svc+0x1c/0x28\n el0_svc+0x40/0xe4\n el0t_64_sync_handler+0x120/0x12c\n el0t_64_sync+0x194/0x198\n\nRoot cause is:\n\nsystemd-random-seed                         kworker\n----------------------------------------------------------------------\n___mark_inode_dirty                     inode_switch_wbs_work_fn\n\n  spin_lock(&inode-\u003ei_lock);\n  inode_attach_wb\n  locked_inode_to_wb_and_lock_list\n     get inode-\u003ei_wb\n     spin_unlock(&inode-\u003ei_lock);\n     spin_lock(&wb-\u003elist_lock)\n  spin_lock(&inode-\u003ei_lock)\n  inode_io_list_move_locked\n  spin_unlock(&wb-\u003elist_lock)\n  spin_unlock(&inode-\u003ei_lock)\n                                    spin_lock(&old_wb-\u003elist_lock)\n                                      inode_do_switch_wbs\n                                        spin_lock(&inode-\u003ei_lock)\n                                        inode-\u003ei_wb = new_wb\n                                        spin_unlock(&inode-\u003ei_lock)\n                                    spin_unlock(&old_wb-\u003elist_lock)\n                                    wb_put_many(old_wb, nr_switched)\n                                      cgwb_release\n                                      old wb released\n  wb_wakeup_delayed() accesses wb,\n  then trigger the use-after-free\n  issue\n\nFix this race condition by holding inode spinlock until\nwb_wakeup_delayed() finished.","modified":"2026-04-02T12:48:11.691208Z","published":"2025-09-19T15:26:35.725Z","related":["SUSE-SU-2025:21040-1","SUSE-SU-2025:21052-1","SUSE-SU-2025:21056-1","SUSE-SU-2025:21064-1","SUSE-SU-2025:21080-1","SUSE-SU-2025:21147-1","SUSE-SU-2025:21180-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4128-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4140-1","SUSE-SU-2025:4141-1","SUSE-SU-2025:4189-1","SUSE-SU-2025:4301-1","openSUSE-SU-2025:20091-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39866.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1edc2feb9c759a9883dfe81cb5ed231412d8b2e4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b187c976111960e6e54a6b1fff724f6e3d39406c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bf89b1f87c72df79cf76203f71fbf8349cd5c9de"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c8c14adf80bd1a6e4a1d7ee9c2a816881c26d17a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d02d2c98d25793902f65803ab853b592c7a96b29"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e2a14bbae5d8bacaa301362744a110e2be40a3a3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e63052921f1b25a836feb1500b841bff7a4a0456"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39866.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39866"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0747259d13febfcc838980a63c414c9b920cea6f"},{"fixed":"e2a14bbae5d8bacaa301362744a110e2be40a3a3"},{"fixed":"b187c976111960e6e54a6b1fff724f6e3d39406c"},{"fixed":"1edc2feb9c759a9883dfe81cb5ed231412d8b2e4"},{"fixed":"bf89b1f87c72df79cf76203f71fbf8349cd5c9de"},{"fixed":"e63052921f1b25a836feb1500b841bff7a4a0456"},{"fixed":"c8c14adf80bd1a6e4a1d7ee9c2a816881c26d17a"},{"fixed":"d02d2c98d25793902f65803ab853b592c7a96b29"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39866.json"}}],"schema_version":"1.7.5"}