{"id":"CVE-2026-31450","summary":"ext4: publish jinode after initialization","details":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: publish jinode after initialization\n\next4_inode_attach_jinode() publishes ei-\u003ejinode to concurrent users.\nIt used to set ei-\u003ejinode before jbd2_journal_init_jbd_inode(),\nallowing a reader to observe a non-NULL jinode with i_vfs_inode\nstill unset.\n\nThe fast commit flush path can then pass this jinode to\njbd2_wait_inode_data(), which dereferences i_vfs_inode-\u003ei_mapping and\nmay crash.\n\nBelow is the crash I observe:\n```\nBUG: unable to handle page fault for address: 000000010beb47f4\nPGD 110e51067 P4D 110e51067 PUD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 1 UID: 0 PID: 4850 Comm: fc_fsync_bench_ Not tainted 6.18.0-00764-g795a690c06a5 #1 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014\nRIP: 0010:xas_find_marked+0x3d/0x2e0\nCode: e0 03 48 83 f8 02 0f 84 f0 01 00 00 48 8b 47 08 48 89 c3 48 39 c6 0f 82 fd 01 00 00 48 85 c9 74 3d 48 83 f9 03 77 63 4c 8b 0f \u003c49\u003e 8b 71 08 48 c7 47 18 00 00 00 00 48 89 f1 83 e1 03 48 83 f9 02\nRSP: 0018:ffffbbee806e7bf0 EFLAGS: 00010246\nRAX: 000000000010beb4 RBX: 000000000010beb4 RCX: 0000000000000003\nRDX: 0000000000000001 RSI: 0000002000300000 RDI: ffffbbee806e7c10\nRBP: 0000000000000001 R08: 0000002000300000 R09: 000000010beb47ec\nR10: ffff9ea494590090 R11: 0000000000000000 R12: 0000002000300000\nR13: ffffbbee806e7c90 R14: ffff9ea494513788 R15: ffffbbee806e7c88\nFS: 00007fc2f9e3e6c0(0000) GS:ffff9ea6b1444000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 000000010beb47f4 CR3: 0000000119ac5000 CR4: 0000000000750ef0\nPKRU: 55555554\nCall Trace:\n\u003cTASK\u003e\nfilemap_get_folios_tag+0x87/0x2a0\n__filemap_fdatawait_range+0x5f/0xd0\n? srso_alias_return_thunk+0x5/0xfbef5\n? __schedule+0x3e7/0x10c0\n? srso_alias_return_thunk+0x5/0xfbef5\n? srso_alias_return_thunk+0x5/0xfbef5\n? srso_alias_return_thunk+0x5/0xfbef5\n? preempt_count_sub+0x5f/0x80\n? srso_alias_return_thunk+0x5/0xfbef5\n? cap_safe_nice+0x37/0x70\n? srso_alias_return_thunk+0x5/0xfbef5\n? preempt_count_sub+0x5f/0x80\n? srso_alias_return_thunk+0x5/0xfbef5\nfilemap_fdatawait_range_keep_errors+0x12/0x40\next4_fc_commit+0x697/0x8b0\n? ext4_file_write_iter+0x64b/0x950\n? srso_alias_return_thunk+0x5/0xfbef5\n? preempt_count_sub+0x5f/0x80\n? srso_alias_return_thunk+0x5/0xfbef5\n? vfs_write+0x356/0x480\n? srso_alias_return_thunk+0x5/0xfbef5\n? preempt_count_sub+0x5f/0x80\next4_sync_file+0xf7/0x370\ndo_fsync+0x3b/0x80\n? syscall_trace_enter+0x108/0x1d0\n__x64_sys_fdatasync+0x16/0x20\ndo_syscall_64+0x62/0x2c0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\n...\n```\n\nFix this by initializing the jbd2_inode first.\nUse smp_wmb() and WRITE_ONCE() to publish ei-\u003ejinode after\ninitialization. Readers use READ_ONCE() to fetch the pointer.","modified":"2026-07-09T18:31:33.467501727Z","published":"2026-04-22T13:53:45.532Z","related":["SUSE-SU-2026:22521-1","SUSE-SU-2026:22522-1","SUSE-SU-2026:2799-1","SUSE-SU-2026:2800-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31450.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1aec30021edd410b986c156f195f3d23959a9d11"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2d2b648960147d078b000b9a7494017082024366"},{"type":"WEB","url":"https://git.kernel.org/stable/c/33f486987af21531a7b18973d11795ede3da9ddd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4855a59e21789c79f003a9b5f4135c95a7495c6b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a070d5a872ffe0e0fe5c46eda6386140ded39adb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/be54c0055407a73b60349c093c8ce621cb8fa232"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e4325e84727e539c8597bd5b8491349f57f7fb17"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e76bcb727e4874a2f9d0297f8e3f8eced89b0764"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31450.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31450"},{"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":"a361293f5fedea0016a10599f409631a15d47ee7"},{"fixed":"2d2b648960147d078b000b9a7494017082024366"},{"fixed":"e4325e84727e539c8597bd5b8491349f57f7fb17"},{"fixed":"be54c0055407a73b60349c093c8ce621cb8fa232"},{"fixed":"a070d5a872ffe0e0fe5c46eda6386140ded39adb"},{"fixed":"e76bcb727e4874a2f9d0297f8e3f8eced89b0764"},{"fixed":"4855a59e21789c79f003a9b5f4135c95a7495c6b"},{"fixed":"33f486987af21531a7b18973d11795ede3da9ddd"},{"fixed":"1aec30021edd410b986c156f195f3d23959a9d11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31450.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.11.0"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.168"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31450.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}