================================================================== BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline] BUG: KASAN: use-after-free in __d_alloc+0x19a/0x950 fs/dcache.c:1775 Read of size 5 at addr ffff88806b296520 by task kdevtmpfs/22 CPU: 1 PID: 22 Comm: kdevtmpfs Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 print_address_description.constprop.0.cold+0x6c/0x2d6 mm/kasan/report.c:256 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 memcpy+0x20/0x60 mm/kasan/shadow.c:65 memcpy include/linux/fortify-string.h:191 [inline] __d_alloc+0x19a/0x950 fs/dcache.c:1775 d_alloc+0x4a/0x230 fs/dcache.c:1823 __lookup_hash+0xc8/0x180 fs/namei.c:1554 kern_path_locked+0x17e/0x320 fs/namei.c:2567 handle_remove+0xa2/0x5fe drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x1b9/0x2a3 drivers/base/devtmpfs.c:437 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 22: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x80/0xa0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc mm/slab.c:3323 [inline] kmem_cache_alloc+0x25f/0x540 mm/slab.c:3507 getname_kernel+0x4e/0x370 fs/namei.c:226 kern_path_locked+0x71/0x320 fs/namei.c:2558 handle_remove+0xa2/0x5fe drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x1b9/0x2a3 drivers/base/devtmpfs.c:437 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 22: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xd1/0x110 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] __cache_free mm/slab.c:3445 [inline] kmem_cache_free+0x6c/0x200 mm/slab.c:3740 putname.part.0+0xe1/0x120 fs/namei.c:270 putname include/linux/err.h:41 [inline] filename_parentat fs/namei.c:2547 [inline] kern_path_locked+0xc2/0x320 fs/namei.c:2558 handle_remove+0xa2/0x5fe drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x1b9/0x2a3 drivers/base/devtmpfs.c:437 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff88806b296500 which belongs to the cache names_cache of size 4096 The buggy address is located 32 bytes inside of 4096-byte region [ffff88806b296500, ffff88806b297500) The buggy address belongs to the page: page:ffffea0001aca580 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6b296 head:ffffea0001aca580 order:1 compound_mapcount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001aca488 ffffea0001acae08 ffff8880114ba600 raw: 0000000000000000 ffff88806b296500 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 1, ts 76806714521, free_ts 15501535317 prep_new_page mm/page_alloc.c:2436 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4168 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5390 __alloc_pages_node include/linux/gfp.h:570 [inline] kmem_getpages mm/slab.c:1377 [inline] cache_grow_begin+0x75/0x460 mm/slab.c:2593 cache_alloc_refill+0x27f/0x380 mm/slab.c:2965 ____cache_alloc mm/slab.c:3048 [inline] ____cache_alloc mm/slab.c:3031 [inline] __do_cache_alloc mm/slab.c:3275 [inline] slab_alloc mm/slab.c:3316 [inline] kmem_cache_alloc+0x454/0x540 mm/slab.c:3507 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138 getname_flags+0x9a/0xe0 include/linux/audit.h:319 user_path_at_empty+0x2b/0x90 fs/namei.c:2801 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0x142/0x390 fs/stat.c:221 vfs_fstatat fs/stat.c:243 [inline] vfs_lstat include/linux/fs.h:3356 [inline] __do_sys_newlstat+0x91/0x110 fs/stat.c:398 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1346 [inline] free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397 free_unref_page_prepare mm/page_alloc.c:3332 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3411 free_contig_range+0xa8/0xf0 mm/page_alloc.c:9269 destroy_args+0xa8/0x646 mm/debug_vm_pgtable.c:1016 debug_vm_pgtable+0x295b/0x29ed mm/debug_vm_pgtable.c:1329 do_one_initcall+0x103/0x650 init/main.c:1287 do_initcall_level init/main.c:1360 [inline] do_initcalls init/main.c:1376 [inline] do_basic_setup init/main.c:1396 [inline] kernel_init_freeable+0x6b8/0x741 init/main.c:1598 kernel_init+0x1a/0x1d0 init/main.c:1490 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff88806b296400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88806b296480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88806b296500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88806b296580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88806b296600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================