================================================================== BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline] BUG: KASAN: use-after-free in __d_alloc+0x161/0x950 fs/dcache.c:1775 Read of size 5 at addr ffff888015414420 by task kdevtmpfs/22 CPU: 0 PID: 22 Comm: kdevtmpfs Not tainted 5.14.0-rc7-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+0x57/0x7d lib/dump_stack.c:105 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:436 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+0x161/0x950 fs/dcache.c:1775 d_alloc+0x3f/0x200 fs/dcache.c:1823 __lookup_hash+0x97/0x140 fs/namei.c:1554 kern_path_locked+0x146/0x300 fs/namei.c:2567 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 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+0x83/0xb0 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_node mm/slub.c:2959 [inline] slab_alloc mm/slub.c:2967 [inline] kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2972 getname_kernel+0x48/0x330 fs/namei.c:226 kern_path_locked+0x6f/0x300 fs/namei.c:2558 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 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+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1628 [inline] slab_free_freelist_hook+0xe3/0x250 mm/slub.c:1653 slab_free mm/slub.c:3213 [inline] kmem_cache_free+0x8a/0x5b0 mm/slub.c:3229 putname include/linux/err.h:41 [inline] filename_parentat fs/namei.c:2547 [inline] kern_path_locked+0xa7/0x300 fs/namei.c:2558 handle_remove+0x9a/0x4fa drivers/base/devtmpfs.c:312 handle drivers/base/devtmpfs.c:382 [inline] devtmpfs_work_loop drivers/base/devtmpfs.c:395 [inline] devtmpfsd+0x176/0x24e drivers/base/devtmpfs.c:437 kthread+0x38b/0x460 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff888015414400 which belongs to the cache names_cache of size 4096 The buggy address is located 32 bytes inside of 4096-byte region [ffff888015414400, ffff888015415400) The buggy address belongs to the page: page:ffffea0000550400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15410 head:ffffea0000550400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff88800fdc43c0 raw: 0000000000000000 0000000080070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4870, ts 430594386934, free_ts 430594238103 prep_new_page mm/page_alloc.c:2436 [inline] get_page_from_freelist+0xa6f/0x2f50 mm/page_alloc.c:4168 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5390 alloc_slab_page mm/slub.c:1691 [inline] allocate_slab+0x32e/0x4b0 mm/slub.c:1831 new_slab mm/slub.c:1894 [inline] new_slab_objects mm/slub.c:2640 [inline] ___slab_alloc+0x4ba/0x820 mm/slub.c:2803 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2843 slab_alloc_node mm/slub.c:2925 [inline] slab_alloc mm/slub.c:2967 [inline] kmem_cache_alloc+0x3e1/0x4a0 mm/slub.c:2972 getname_flags.part.0+0x4a/0x440 fs/namei.c:138 do_sys_openat2+0xd2/0x360 fs/open.c:1198 do_sys_open fs/open.c:1220 [inline] __do_sys_open fs/open.c:1228 [inline] __se_sys_open fs/open.c:1224 [inline] __x64_sys_open+0xfd/0x1a0 fs/open.c:1224 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 unfreeze_partials+0x17c/0x1d0 mm/slub.c:2421 put_cpu_partial+0x13d/0x230 mm/slub.c:2457 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x95/0xb0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:2959 [inline] slab_alloc mm/slub.c:2967 [inline] kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2972 prepare_creds+0x39/0x610 kernel/cred.c:262 access_override_creds fs/open.c:355 [inline] do_faccessat+0x273/0x660 fs/open.c:419 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 Memory state around the buggy address: ffff888015414300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888015414380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888015414400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888015414480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888015414500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================