loop7: rw=524288, sector=34359738360, nr_sectors = 8 limit=16 syz.7.1959: attempt to access beyond end of device loop7: rw=524288, sector=8, nr_sectors = 16 limit=16 ================================================================== BUG: KASAN: slab-out-of-bounds in memcpy_to_page include/linux/highmem.h:403 [inline] BUG: KASAN: slab-out-of-bounds in z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346 Read of size 4096 at addr ffff0000c9b49000 by task syz.7.1959/11447 CPU: 0 PID: 11447 Comm: syz.7.1959 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x258/0x290 mm/kasan/generic.c:189 memcpy+0x48/0x90 mm/kasan/shadow.c:65 memcpy_to_page include/linux/highmem.h:403 [inline] z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346 z_erofs_decompress+0x9c/0xd4 fs/erofs/decompressor.c:434 z_erofs_decompress_pcluster fs/erofs/zdata.c:1159 [inline] z_erofs_decompress_queue+0x100c/0x1b40 fs/erofs/zdata.c:1240 z_erofs_runqueue+0x152c/0x16cc fs/erofs/zdata.c:1603 z_erofs_read_folio+0x2d8/0x5c8 fs/erofs/zdata.c:1693 filemap_read_folio+0x134/0x384 mm/filemap.c:2490 filemap_update_page mm/filemap.c:2575 [inline] filemap_get_pages mm/filemap.c:2689 [inline] filemap_read+0x12cc/0x2104 mm/filemap.c:2759 generic_file_read_iter+0xf8/0x5c4 mm/filemap.c:2941 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x3d4/0x7f0 fs/read_write.c:470 ksys_read+0x12c/0x224 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:621 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Allocated by task 11431: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x74/0x430 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x22c/0x308 mm/slub.c:3383 kmem_cache_zalloc include/linux/slab.h:689 [inline] __kernfs_new_node+0xec/0x5f4 fs/kernfs/dir.c:614 kernfs_new_node+0x11c/0x22c fs/kernfs/dir.c:690 kernfs_create_dir_ns+0x58/0x12c fs/kernfs/dir.c:1046 sysfs_create_dir_ns+0x120/0x264 fs/sysfs/dir.c:59 create_dir lib/kobject.c:63 [inline] kobject_add_internal+0x598/0xb08 lib/kobject.c:231 kobject_add_varg lib/kobject.c:366 [inline] kobject_add+0x140/0x20c lib/kobject.c:418 device_add+0x3f0/0xf90 drivers/base/core.c:3632 device_create_groups_vargs+0x1e8/0x280 drivers/base/core.c:4391 device_create+0xf4/0x148 drivers/base/core.c:4433 bdi_register_va+0x150/0x828 mm/backing-dev.c:877 super_setup_bdi_name+0x100/0x208 fs/super.c:1632 fuse_bdi_init fs/fuse/inode.c:1385 [inline] fuse_fill_super_common+0x528/0xde0 fs/fuse/inode.c:1662 fuse_fill_super+0x17c/0x1e8 fs/fuse/inode.c:1738 vfs_get_super fs/super.c:1211 [inline] get_tree_nodev+0xb4/0x16c fs/super.c:1241 fuse_get_tree+0x2d8/0x434 fs/fuse/inode.c:1813 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000c9b49000 which belongs to the cache kernfs_node_cache of size 168 The buggy address is located 0 bytes inside of 168-byte region [ffff0000c9b49000, ffff0000c9b490a8) The buggy address belongs to the physical page: page:000000002cfe1937 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109b49 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc000342d900 dead000000000002 ffff0000c03dca80 raw: 0000000000000000 0000000000110011 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c9b48f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000c9b49000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff0000c9b49080: 00 00 00 00 00 fc fc fc fc fc fc fc fc fa fb fb ^ ffff0000c9b49100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c9b49180: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb ================================================================== syz.7.1959: attempt to access beyond end of device loop7: rw=0, sector=34359738360, nr_sectors = 8 limit=16