Hello, syzbot found the following issue on: HEAD commit: dcc5c6f0 Merge tag 'x86-urgent-2020-08-30' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11e8ca85900000 kernel config: https://syzkaller.appspot.com/x/.config?x=891ca5711a9f1650 dashboard link: https://syzkaller.appspot.com/bug?extid=6448f3c229bc52b82f69 compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=154e2285900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16f6e915900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6448f3c229bc52b82f69@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in kobject_put+0x245/0x2c0 lib/kobject.c:748 Read of size 1 at addr ffff8880a384e9bc by task syz-executor027/6982 CPU: 0 PID: 6982 Comm: syz-executor027 Not tainted 5.9.0-rc2-syzkaller #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+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 kobject_put+0x245/0x2c0 lib/kobject.c:748 delete_partition block/partitions/core.c:324 [inline] bdev_del_partition+0x26a/0x380 block/partitions/core.c:549 blkpg_do_ioctl+0x12b/0x2e0 block/ioctl.c:33 blkpg_ioctl block/ioctl.c:69 [inline] blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589 block_ioctl+0xbc/0x100 fs/block_dev.c:1871 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446959 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4a7a555d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 0000000000446959 RDX: 0000000020000000 RSI: 0000000000001269 RDI: 0000000000000005 RBP: 00000000006dbc30 R08: 00007f4a7a556700 R09: 0000000000000000 R10: 00007f4a7a556700 R11: 0000000000000246 R12: 00000000006dbc3c R13: 00000000000000a9 R14: 00b747111e42e3ec R15: 02ba2b7a04b8ac00 Allocated by task 6977: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 kmem_cache_alloc_trace+0x1e4/0x2e0 mm/slab.c:3550 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:666 [inline] kobject_create lib/kobject.c:783 [inline] kobject_create_and_add+0x57/0x240 lib/kobject.c:809 add_partition+0x884/0xcb0 block/partitions/core.c:443 bdev_add_partition+0x1c9/0x230 block/partitions/core.c:518 blkpg_do_ioctl+0x295/0x2e0 block/ioctl.c:52 blkpg_ioctl block/ioctl.c:69 [inline] blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589 block_ioctl+0xbc/0x100 fs/block_dev.c:1871 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6979: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x113/0x200 mm/slab.c:3756 kobject_cleanup lib/kobject.c:704 [inline] kobject_release lib/kobject.c:735 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1a0/0x2c0 lib/kobject.c:752 delete_partition block/partitions/core.c:324 [inline] bdev_del_partition+0x26a/0x380 block/partitions/core.c:549 blkpg_do_ioctl+0x12b/0x2e0 block/ioctl.c:33 blkpg_ioctl block/ioctl.c:69 [inline] blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589 block_ioctl+0xbc/0x100 fs/block_dev.c:1871 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880a384e980 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 60 bytes inside of 64-byte region [ffff8880a384e980, ffff8880a384e9c0) The buggy address belongs to the page: page:00000000f601aef4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa384e flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea000263b548 ffffea00029bbac8 ffff8880aa440200 raw: 0000000000000000 ffff8880a384e000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a384e880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff8880a384e900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff8880a384e980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff8880a384ea00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff8880a384ea80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
