{"id":"AZL-102275","summary":"CVE-2026-92500 affecting package kernel 6.6.150.1-1","details":"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.","modified":"2026-09-18T14:15:15.615492848Z","published":"2026-09-17T17:17:52Z","upstream":["CVE-2026-92500"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-92500"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102275.json"}}],"schema_version":"1.9.0"}