================================================================== BUG: KASAN: use-after-free in dev_uevent+0x3dd/0x730 drivers/base/core.c:1863 Read of size 8 at addr ffff8881935e2058 by task systemd-udevd/32167 CPU: 0 PID: 32167 Comm: systemd-udevd Not tainted 5.4.121-syzkaller-00750-g54f14b62ffed #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x24e lib/dump_stack.c:118 print_address_description+0x9b/0x650 mm/kasan/report.c:384 __kasan_report+0x182/0x260 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:641 dev_uevent+0x3dd/0x730 drivers/base/core.c:1863 uevent_show+0x1a2/0x2e0 drivers/base/core.c:1934 dev_attr_show+0x50/0xc0 drivers/base/core.c:1638 sysfs_kf_seq_show+0x265/0x3e0 fs/sysfs/file.c:61 seq_read+0x4aa/0xd10 fs/seq_file.c:229 __vfs_read+0x103/0x770 fs/read_write.c:425 vfs_read+0x161/0x370 fs/read_write.c:461 ksys_read+0x186/0x2b0 fs/read_write.c:587 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fb1cbf35910 Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 de 9b 01 00 48 89 04 24 RSP: 002b:00007ffd2dc5d0b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000556a694bed60 RCX: 00007fb1cbf35910 RDX: 0000000000001000 RSI: 0000556a694ac110 RDI: 0000000000000007 RBP: 00007fb1cc1f0440 R08: 00007fb1cc1f41a8 R09: 0000000000001010 R10: 0000556a694bed60 R11: 0000000000000246 R12: 0000000000001000 R13: 0000000000000d68 R14: 0000556a694ac110 R15: 00007fb1cc1ef900 Allocated by task 32114: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x137/0x1e0 mm/kasan/common.c:517 kmem_cache_alloc_trace+0x139/0x2b0 mm/slub.c:2848 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:690 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:182 [inline] raw_open+0x84/0x370 drivers/usb/gadget/legacy/raw_gadget.c:372 misc_open+0x346/0x3c0 drivers/char/misc.c:141 chrdev_open+0x5fb/0x680 fs/char_dev.c:414 do_dentry_open+0x949/0x1100 fs/open.c:796 do_last fs/namei.c:3495 [inline] path_openat+0x1127/0x3da0 fs/namei.c:3612 do_filp_open+0x208/0x450 fs/namei.c:3642 do_sys_open+0x383/0x7c0 fs/open.c:1113 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 32114: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:333 [inline] __kasan_slab_free+0x18a/0x240 mm/kasan/common.c:475 slab_free_hook mm/slub.c:1454 [inline] slab_free_freelist_hook+0x7b/0x150 mm/slub.c:1492 slab_free mm/slub.c:3072 [inline] kfree+0xe0/0x660 mm/slub.c:4061 raw_release+0x130/0x1e0 drivers/usb/gadget/legacy/raw_gadget.c:411 __fput+0x27d/0x6c0 fs/file_table.c:281 task_work_run+0x186/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xcb9/0x2bf0 kernel/exit.c:812 do_group_exit+0x15c/0x2c0 kernel/exit.c:910 get_signal+0x164f/0x1fc0 kernel/signal.c:2745 do_signal+0x8d/0x610 arch/x86/kernel/signal.c:793 exit_to_usermode_loop arch/x86/entry/common.c:159 [inline] prepare_exit_to_usermode+0x207/0x310 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8881935e2000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 88 bytes inside of 4096-byte region [ffff8881935e2000, ffff8881935e3000) The buggy address belongs to the page: page:ffffea00064d7800 refcount:1 mapcount:0 mapping:ffff8881f5c0c280 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0c280 raw: 0000000000000000 0000000000040004 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) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x19a/0x380 mm/page_alloc.c:2171 get_page_from_freelist+0x550/0x8b0 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x3a2/0x880 mm/page_alloc.c:4855 alloc_slab_page+0x39/0x3e0 mm/slub.c:342 allocate_slab mm/slub.c:1675 [inline] new_slab+0x97/0x460 mm/slub.c:1741 new_slab_objects mm/slub.c:2498 [inline] ___slab_alloc+0x330/0x4c0 mm/slub.c:2659 __slab_alloc mm/slub.c:2699 [inline] slab_alloc_node mm/slub.c:2784 [inline] slab_alloc mm/slub.c:2829 [inline] kmem_cache_alloc_trace+0x199/0x2b0 mm/slub.c:2846 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:690 [inline] kobject_uevent_env+0x252/0x1000 lib/kobject_uevent.c:524 device_del+0xf07/0x1020 drivers/base/core.c:3086 usb_disable_device+0x356/0x640 drivers/usb/core/message.c:1271 usb_disconnect+0x346/0x880 drivers/usb/core/hub.c:2217 hub_port_connect drivers/usb/core/hub.c:4974 [inline] hub_port_connect_change drivers/usb/core/hub.c:5238 [inline] port_event drivers/usb/core/hub.c:5384 [inline] hub_event+0x1cac/0x4e30 drivers/usb/core/hub.c:5466 process_one_work+0x679/0x1030 kernel/workqueue.c:2277 worker_thread+0xa6f/0x1400 kernel/workqueue.c:2423 kthread+0x30f/0x330 kernel/kthread.c:268 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] free_pcp_prepare+0x1a9/0x270 mm/page_alloc.c:1233 free_unref_page_prepare mm/page_alloc.c:3085 [inline] free_unref_page_list+0x115/0x6c0 mm/page_alloc.c:3154 release_pages+0x98f/0x9d0 mm/swap.c:842 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:184 [inline] tlb_flush_mmu+0x77f/0x910 mm/mmu_gather.c:191 tlb_finish_mmu+0xcb/0x200 mm/mmu_gather.c:272 exit_mmap+0x2e8/0x540 mm/mmap.c:3176 __mmput+0x34/0x240 kernel/fork.c:1089 exit_mm kernel/exit.c:489 [inline] do_exit+0xc19/0x2bf0 kernel/exit.c:799 do_group_exit+0x15c/0x2c0 kernel/exit.c:910 __do_sys_exit_group+0x13/0x20 kernel/exit.c:921 __ia32_sys_exit_group+0x0/0x40 kernel/exit.c:919 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:919 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Memory state around the buggy address: ffff8881935e1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881935e1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881935e2000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881935e2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881935e2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================