Hello, syzbot found the following issue on: HEAD commit: 7b4ea945 Revert "x86/mm/64: Do not sync vmalloc/ioremap ma.. git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=108adf32900000 kernel config: https://syzkaller.appspot.com/x/.config?x=72a84c46d0c668c dashboard link: https://syzkaller.appspot.com/bug?extid=9e04e2df4a32fb661daf 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+9e04e2df4a32fb661daf@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in usb_submit_urb+0x10c4/0x13e0 drivers/usb/core/urb.c:368 Read of size 4 at addr ffff8881caa52018 by task syz-executor.3/13922 CPU: 1 PID: 13922 Comm: syz-executor.3 Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xf6/0x16e lib/dump_stack.c:118 print_address_description.constprop.0+0x1a/0x210 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x37/0x7c mm/kasan/report.c:530 usb_submit_urb+0x10c4/0x13e0 drivers/usb/core/urb.c:368 service_outstanding_interrupt.part.0+0x5f/0xa0 drivers/usb/class/cdc-wdm.c:463 service_outstanding_interrupt drivers/usb/class/cdc-wdm.c:458 [inline] wdm_read+0x9a0/0xbd0 drivers/usb/class/cdc-wdm.c:576 vfs_read+0x1df/0x520 fs/read_write.c:479 ksys_read+0x12d/0x250 fs/read_write.c:607 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ce79 Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8d2099fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00000000000252c0 RCX: 000000000045ce79 RDX: 00000000000000f2 RSI: 0000000020000100 RDI: 0000000000000003 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffd66f595ff R14: 00007f8d209a09c0 R15: 000000000118bf2c Allocated by task 4524: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] usb_alloc_dev+0x51/0xf67 drivers/usb/core/usb.c:582 hub_port_connect drivers/usb/core/hub.c:5114 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x1dff/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Freed by task 5477: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0x116/0x160 mm/kasan/common.c:455 slab_free_hook mm/slub.c:1474 [inline] slab_free_freelist_hook+0x53/0x140 mm/slub.c:1507 slab_free mm/slub.c:3072 [inline] kfree+0xbc/0x2c0 mm/slub.c:4052 device_release+0x71/0x200 drivers/base/core.c:1800 kobject_cleanup lib/kobject.c:704 [inline] kobject_release lib/kobject.c:735 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x540 lib/kobject.c:752 put_device+0x1b/0x30 drivers/base/core.c:3029 hub_port_connect drivers/usb/core/hub.c:5059 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x1c93/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 The buggy address belongs to the object at ffff8881caa52000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 24 bytes inside of 2048-byte region [ffff8881caa52000, ffff8881caa52800) The buggy address belongs to the page: page:ffffea00072a9400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea00072a9400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x200000000010200(slab|head) raw: 0200000000010200 0000000000000000 0000000100000001 ffff8881da00c000 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881caa51f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881caa51f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881caa52000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881caa52080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881caa52100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. 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