"value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncachefiles: fix slab-use-after-free in fscache_withdraw_volume()\n\nWe got the following issue in our fault injection stress test:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in fscache_withdraw_volume+0x2e1/0x370\nRead of size 4 at addr ffff88810680be08 by task ondemand-04-dae/5798\n\nCPU: 0 PID: 5798 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #565\nCall Trace:\n kasan_check_range+0xf6/0x1b0\n fscache_withdraw_volume+0x2e1/0x370\n cachefiles_withdraw_volume+0x31/0x50\n cachefiles_withdraw_cache+0x3ad/0x900\n cachefiles_put_unbind_pincount+0x1f6/0x250\n cachefiles_daemon_release+0x13b/0x290\n __fput+0x204/0xa00\n task_work_run+0x139/0x230\n\nAllocated by task 5820:\n __kmalloc+0x1df/0x4b0\n fscache_alloc_volume+0x70/0x600\n __fscache_acquire_volume+0x1c/0x610\n erofs_fscache_register_volume+0x96/0x1a0\n erofs_fscache_register_fs+0x49a/0x690\n erofs_fc_fill_super+0x6c0/0xcc0\n vfs_get_super+0xa9/0x140\n vfs_get_tree+0x8e/0x300\n do_new_mount+0x28c/0x580\n [...]\n\nFreed by task 5820:\n kfree+0xf1/0x2c0\n fscache_put_volume.part.0+0x5cb/0x9e0\n erofs_fscache_unregister_fs+0x157/0x1b0\n erofs_kill_sb+0xd9/0x1c0\n deactivate_locked_super+0xa3/0x100\n vfs_get_super+0x105/0x140\n vfs_get_tree+0x8e/0x300\n do_new_mount+0x28c/0x580\n [...]\n==================================================================\n\nFollowing is the process that triggers the issue:\n\n mount failed | daemon exit\n------------------------------------------------------------\n deactivate_locked_super cachefiles_daemon_release\n erofs_kill_sb\n erofs_fscache_unregister_fs\n fscache_relinquish_volume\n __fscache_relinquish_volume\n fscache_put_volume(fscache_volume, fscache_volume_put_relinquish)\n zero = __refcount_dec_and_test(&fscache_volume->ref, &ref);\n cachefiles_put_unbind_pincount\n cachefiles_daemon_unbind\n cachefiles_withdraw_cache\n cachefiles_withdraw_volumes\n list_del_init(&volume->cache_link)\n fscache_free_volume(fscache_volume)\n cache->ops->free_volume\n cachefiles_free_volume\n list_del_init(&cachefiles_volume->cache_link);\n kfree(fscache_volume)\n cachefiles_withdraw_volume\n fscache_withdraw_volume\n fscache_volume->n_accesses\n // fscache_volume UAF !!!\n\nThe fscache_volume in cache->volumes must not have been freed yet, but its\nreference count may be 0. So use the new fscache_try_get_volume() helper\nfunction try to get its reference count.\n\nIf the reference count of fscache_volume is 0, fscache_put_volume() is\nfreeing it, so wait for it to be removed from cache->volumes.\n\nIf its reference count is not 0, call cachefiles_withdraw_volume() with\nreference count protection to avoid the above issue."