Hello, syzbot found the following crash on: HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15f83346100000 kernel config: https://syzkaller.appspot.com/x/.config?x=d195fe572fb15312 dashboard link: https://syzkaller.appspot.com/bug?extid=a7ebdb01bb2cc165cab6 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17046c66100000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=140a8a3e100000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a7ebdb01bb2cc165cab6@xxxxxxxxxxxxxxxxxxxxxxxxx smsc95xx 1-1:1.0 eth6: Failed to read reg index 0x00000114: -19 smsc95xx 1-1:1.0 eth6 (unregistering): Error reading MII_ACCESS smsc95xx 1-1:1.0 eth6 (unregistered): MII is busy in smsc95xx_mdio_read ================================================================== BUG: KASAN: use-after-free in atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline] BUG: KASAN: use-after-free in atomic_long_read include/asm-generic/atomic-long.h:28 [inline] BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0x8e/0x660 kernel/locking/mutex.c:1237 Read of size 8 at addr ffff888094310c38 by task kworker/0:4/6949 CPU: 0 PID: 6949 Comm: kworker/0:4 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events check_carrier Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:192 atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline] atomic_long_read include/asm-generic/atomic-long.h:28 [inline] __mutex_unlock_slowpath+0x8e/0x660 kernel/locking/mutex.c:1237 __smsc95xx_mdio_read+0x1bc/0x210 drivers/net/usb/smsc95xx.c:217 smsc95xx_mdio_read drivers/net/usb/smsc95xx.c:278 [inline] check_carrier+0xf3/0x1d0 drivers/net/usb/smsc95xx.c:644 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Allocated by task 6949: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc mm/kasan/common.c:494 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467 kmalloc_node include/linux/slab.h:578 [inline] kvmalloc_node+0xb4/0xf0 mm/util.c:574 kvmalloc include/linux/mm.h:752 [inline] kvzalloc include/linux/mm.h:760 [inline] alloc_netdev_mqs+0x97/0xdc0 net/core/dev.c:9927 usbnet_probe+0x159/0x2600 drivers/net/usb/usbnet.c:1686 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:374 really_probe+0x281/0x6d0 drivers/base/dd.c:520 driver_probe_device+0x104/0x210 drivers/base/dd.c:697 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:804 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431 __device_attach+0x21a/0x360 drivers/base/dd.c:870 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0x132d/0x1c10 drivers/base/core.c:2557 usb_set_configuration+0xec5/0x1740 drivers/usb/core/message.c:2032 usb_generic_driver_probe+0x9d/0xe0 drivers/usb/core/generic.c:241 usb_probe_device+0xc6/0x1f0 drivers/usb/core/driver.c:272 really_probe+0x281/0x6d0 drivers/base/dd.c:520 driver_probe_device+0x104/0x210 drivers/base/dd.c:697 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:804 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431 __device_attach+0x21a/0x360 drivers/base/dd.c:870 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0x132d/0x1c10 drivers/base/core.c:2557 usb_new_device.cold+0x753/0x103d drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x1eca/0x38f0 drivers/usb/core/hub.c:5576 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Freed by task 6849: 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+0xf7/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 kvfree+0x42/0x50 mm/util.c:603 device_release+0x71/0x200 drivers/base/core.c:1394 kobject_cleanup lib/kobject.c:693 [inline] kobject_release lib/kobject.c:722 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1e7/0x2e0 lib/kobject.c:739 put_device+0x1b/0x30 drivers/base/core.c:2656 free_netdev+0x380/0x4a0 net/core/dev.c:10047 usbnet_disconnect+0x1fb/0x270 drivers/net/usb/usbnet.c:1625 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:436 __device_release_driver drivers/base/dd.c:1110 [inline] device_release_driver_internal+0x432/0x500 drivers/base/dd.c:1141 bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:533 device_del+0x481/0xd30 drivers/base/core.c:2734 usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1245 usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2217 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+0x17ca/0x38f0 drivers/usb/core/hub.c:5576 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 The buggy address belongs to the object at ffff888094310000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 3128 bytes inside of 8192-byte region [ffff888094310000, ffff888094312000) The buggy address belongs to the page: page:ffffea000250c400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea000250c400 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0002257808 ffffea0002548608 ffff8880aa0021c0 raw: 0000000000000000 ffff888094310000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888094310b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094310b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888094310c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888094310c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094310d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. 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