"value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()\n\nSyzbot reports a warning as follows:\n\n============================================\nWARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290\nModules linked in:\nCPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7\nRIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419\nCall Trace:\n <TASK>\n ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375\n generic_shutdown_super+0x136/0x2d0 fs/super.c:641\n kill_block_super+0x44/0x90 fs/super.c:1675\n ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327\n[...]\n============================================\n\nThis is because when finding an entry in ext4_xattr_block_cache_find(), if\next4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown\nin the __entry_find(), won't be put away, and eventually trigger the above\nissue in mb_cache_destroy() due to reference count leakage.\n\nSo call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix."