{"id":"CVE-2026-92500","revision":"8176e1af5de74d38a5bbf91b632fc7b6","records":[{"revision":"8176e1af5de74d38a5bbf91b632fc7b6","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-92500","aliases":[],"title":"ext4: use fsdata to track inline data write state and fix race","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: use fsdata to track inline data write state and fix race\n\nInstead of checking the live inode state (ext4_has_inline_data(inode)\nand ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) in the\nwrite_end handlers, use the fsdata parameter of the address space\noperations to explicitly pass down the state in which write_begin\nprepared the write.\n\nA concurrent thread (such as ext4_page_mkwrite()) can convert the\ninline data to an extent between write_begin and write_end. If this\nhappens, the write_end handlers would previously miss the inline\nwrite_end path and fall through to extent-based write_end logic.\nHowever, since block buffers were never allocated in write_begin,\nthis resulted in NULL pointer dereferences or data loss because\nfolio_buffers(folio) was NULL.\n\nDefine EXT4_WRITE_DATA_INLINE (4) as a bit flag (Bit 2), treating\nfsdata as bitwise flags rather than mutually exclusive enums to keep\nstates of the write path independent. Communicate this state via\nfsdata:\n1) ext4_write_begin() and ext4_da_write_begin() set the\n   EXT4_WRITE_DATA_INLINE bit in *fsdata via bitwise OR when an inline\n   write is successfully prepared.\n2) On entry, ext4_write_begin() clears the EXT4_WRITE_DATA_INLINE bit\n   to safely handle VFS retries (where generic_perform_write() bypasses\n   the fsdata initialization on its retry jump).\n3) The write_end handlers perform a bitwise AND to check if the\n   EXT4_WRITE_DATA_INLINE bit is set and invoke the inline write_end\n   helper accordingly.\n\nFurthermore, during a buffered write, ext4_write_inline_data_end()\nacquires the xattr lock after preparing the write. If a concurrent\npage fault (ext4_page_mkwrite()) converts the inline data to an extent\nafter the write_end handlers check the state but before\next4_write_inline_data_end() acquires the xattr write lock, the\nsubsequent check will trigger a kernel panic via\nBUG_ON(!ext4_has_inline_data(inode)).\n\nTo keep git history working and bisectability clean, replace the\nBUG_ON check in ext4_write_inline_data_end() with a graceful error-\nhandling retry path in this same commit. If the inline data is cleared\nafter locking the xattr, we safely release all resources (releasing\niloc.bh, unlocking/putting the folio, stopping the active journal\ntransaction handle) and return 0 (VFS retry) to let the generic write\npath retry the operation safely.","state":0,"publishedAt":"2026-09-17T16:10:14.073+00:00","modifiedAt":"2026-10-19T09:04:06.284+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/ext4/ext4.h\",\n                        \"fs/ext4/inline.c\",\n                        \"fs/ext4/inode.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3fdcfb668fd78ec92d9bc2daddf1d41e2a8a30bb\",\n                            \"lessThan\": \"bd8d74bd46d09905164255b8635fa58b45f41068\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3fdcfb668fd78ec92d9bc2daddf1d41e2a8a30bb\",\n                            \"lessThan\": \"439aedfd7ae868d1d7b4930afe66091cb979cd5c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3fdcfb668fd78ec92d9bc2daddf1d41e2a8a30bb\",\n                            \"lessThan\": \"7edbb323bab2b2a609016014caafdb651c898249\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/ext4/ext4.h\",\n                        \"fs/ext4/inline.c\",\n                        \"fs/ext4/inode.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/bd8d74bd46d09905164255b8635fa58b45f41068","https://git.kernel.org/stable/c/439aedfd7ae868d1d7b4930afe66091cb979cd5c","https://git.kernel.org/stable/c/7edbb323bab2b2a609016014caafdb651c898249"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-92500","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-92500","identifiers":["CVE-2026-92500"]},"retained":false,"historicalAffected":[]}],"coverage":[]}