Hello, syzbot found the following issue on: HEAD commit: b01f250d Add linux-next specific files for 20210129 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=14366378d00000 kernel config: https://syzkaller.appspot.com/x/.config?x=725bc96dc234fda7 dashboard link: https://syzkaller.appspot.com/bug?extid=f91dbbabacae745d334f compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f91dbbabacae745d334f@xxxxxxxxxxxxxxxxxxxxxxxxx block nbd5: Receive control failed (result -107) ================================================================== BUG: KASAN: use-after-free in recv_work+0x2a2/0x2c0 drivers/block/nbd.c:787 Read of size 8 at addr ffff88801181ed20 by task kworker/u5:2/8465 CPU: 1 PID: 8465 Comm: kworker/u5:2 Not tainted 5.11.0-rc5-next-20210129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: knbd5-recv recv_work Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 recv_work+0x2a2/0x2c0 drivers/block/nbd.c:787 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Allocated by task 17044: 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:403 [inline] ____kasan_kmalloc mm/kasan/common.c:434 [inline] ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:406 kasan_slab_alloc include/linux/kasan.h:208 [inline] slab_post_alloc_hook mm/slab.h:516 [inline] slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] __kmalloc_track_caller+0x16c/0x2e0 mm/slub.c:4550 __do_krealloc mm/slab_common.c:1149 [inline] krealloc+0x60/0xa0 mm/slab_common.c:1178 nbd_add_socket+0x263/0x6a0 drivers/block/nbd.c:1044 __nbd_ioctl drivers/block/nbd.c:1369 [inline] nbd_ioctl+0x388/0xa50 drivers/block/nbd.c:1425 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:576 block_ioctl+0xf9/0x140 fs/block_dev.c:1650 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 17044: 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:357 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:364 kasan_slab_free include/linux/kasan.h:191 [inline] slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kfree+0xe5/0x7b0 mm/slub.c:4202 krealloc+0x45/0xa0 mm/slab_common.c:1180 nbd_add_socket+0x263/0x6a0 drivers/block/nbd.c:1044 __nbd_ioctl drivers/block/nbd.c:1369 [inline] nbd_ioctl+0x388/0xa50 drivers/block/nbd.c:1425 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:576 block_ioctl+0xf9/0x140 fs/block_dev.c:1650 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88801181ed20 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff88801181ed20, ffff88801181ed28) The buggy address belongs to the page: page:00000000e0a0f4b5 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1181e flags: 0xfff00000000200(slab) raw: 00fff00000000200 ffffea000053d180 0000000500000005 ffff88800fc41280 raw: ffff88801181ef28 0000000080660062 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88801181ec00: fc 00 fc fc fc fc fa fc fc fc fc 00 fc fc fc fc ffff88801181ec80: fa fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 >ffff88801181ed00: fc fc fc fc fa fc fc fc fc 00 fc fc fc fc 00 fc ^ ffff88801181ed80: fc fc fc 00 fc fc fc fc 00 fc fc fc fc fa fc fc ffff88801181ee00: fc fc 00 fc fc fc fc fa fc fc fc fc 00 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.
