On Thu, Mar 26, 2020 at 1:42 PM Hillf Danton <hdanton@xxxxxxxx> wrote: > > > On Thu, 26 Mar 2020 04:34:16 -0700 > > syzbot found the following crash on: > > > > HEAD commit: e17994d1 usb: core: kcov: collect coverage from usb comple.. > > git tree: https://github.com/google/kasan.git usb-fuzzer > > console output: https://syzkaller.appspot.com/x/log.txt?x=13ee4d4be00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=5d64370c438bc60 > > dashboard link: https://syzkaller.appspot.com/bug?extid=b894396e6110e1df38c4 > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+b894396e6110e1df38c4@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > ================================================================== > > BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] > > BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:134 [inline] > > BUG: KASAN: use-after-free in skb_unref include/linux/skbuff.h:1042 [inline] > > BUG: KASAN: use-after-free in kfree_skb+0x32/0x3d0 net/core/skbuff.c:692 > > Read of size 4 at addr ffff8881d6816494 by task swapper/0/0 > > > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc5-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > Call Trace: > > <IRQ> > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0xef/0x16e lib/dump_stack.c:118 > > print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374 > > __kasan_report.cold+0x37/0x77 mm/kasan/report.c:506 > > kasan_report+0xe/0x20 mm/kasan/common.c:641 > > check_memory_region_inline mm/kasan/generic.c:185 [inline] > > check_memory_region+0x152/0x1c0 mm/kasan/generic.c:192 > > atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] > > refcount_read include/linux/refcount.h:134 [inline] > > skb_unref include/linux/skbuff.h:1042 [inline] > > kfree_skb+0x32/0x3d0 net/core/skbuff.c:692 > > hif_usb_regout_cb+0x14c/0x1b0 drivers/net/wireless/ath/ath9k/hif_usb.c:97 > > __usb_hcd_giveback_urb+0x29a/0x550 drivers/usb/core/hcd.c:1650 > > usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1716 > > dummy_timer+0x1258/0x32ae drivers/usb/gadget/udc/dummy_hcd.c:1966 > > call_timer_fn+0x195/0x6f0 kernel/time/timer.c:1404 > > expire_timers kernel/time/timer.c:1449 [inline] > > __run_timers kernel/time/timer.c:1773 [inline] > > __run_timers kernel/time/timer.c:1740 [inline] > > run_timer_softirq+0x5f9/0x1500 kernel/time/timer.c:1786 > > __do_softirq+0x21e/0x950 kernel/softirq.c:292 > > invoke_softirq kernel/softirq.c:373 [inline] > > irq_exit+0x178/0x1a0 kernel/softirq.c:413 > > exiting_irq arch/x86/include/asm/apic.h:546 [inline] > > smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1146 > > apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 > > </IRQ> > > RIP: 0010:default_idle+0x28/0x300 arch/x86/kernel/process.c:696 > > Code: cc cc 41 56 41 55 65 44 8b 2d 44 77 72 7a 41 54 55 53 0f 1f 44 00 00 e8 b6 62 b5 fb e9 07 00 00 00 0f 00 2d ea 0c 53 00 fb f4 <65> 44 8b 2d 20 77 72 7a 0f 1f 44 00 00 5b 5d 41 5c 41 5d 41 5e c3 > > RSP: 0018:ffffffff87007d80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 > > RAX: 0000000000000007 RBX: ffffffff8702cc40 RCX: 0000000000000000 > > RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff8702d48c > > RBP: fffffbfff0e05988 R08: ffffffff8702cc40 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > > R13: 0000000000000000 R14: ffffffff87e607c0 R15: 0000000000000000 > > cpuidle_idle_call kernel/sched/idle.c:154 [inline] > > do_idle+0x3e0/0x500 kernel/sched/idle.c:269 > > cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361 > > start_kernel+0xe16/0xe5a init/main.c:998 > > secondary_startup_64+0xb6/0xc0 arch/x86/kernel/head_64.S:242 > > > > Allocated by task 3135: > > save_stack+0x1b/0x80 mm/kasan/common.c:72 > > set_track mm/kasan/common.c:80 [inline] > > __kasan_kmalloc mm/kasan/common.c:515 [inline] > > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488 > > slab_post_alloc_hook mm/slab.h:584 [inline] > > slab_alloc_node mm/slub.c:2778 [inline] > > kmem_cache_alloc_node+0xdc/0x330 mm/slub.c:2814 > > __alloc_skb+0xba/0x5a0 net/core/skbuff.c:198 > > alloc_skb include/linux/skbuff.h:1081 [inline] > > htc_connect_service+0x2cc/0x840 drivers/net/wireless/ath/ath9k/htc_hst.c:257 > > ath9k_wmi_connect+0xd2/0x1a0 drivers/net/wireless/ath/ath9k/wmi.c:265 > > ath9k_init_htc_services.constprop.0+0xb4/0x650 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146 > > ath9k_htc_probe_device+0x25a/0x1d80 drivers/net/wireless/ath/ath9k/htc_drv_init.c:959 > > ath9k_htc_hw_init+0x31/0x60 drivers/net/wireless/ath/ath9k/htc_hst.c:501 > > ath9k_hif_usb_firmware_cb+0x26b/0x500 drivers/net/wireless/ath/ath9k/hif_usb.c:1187 > > request_firmware_work_func+0x126/0x242 drivers/base/firmware_loader/main.c:976 > > process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 > > worker_thread+0x96/0xe20 kernel/workqueue.c:2410 > > kthread+0x318/0x420 kernel/kthread.c:255 > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > > Freed by task 3135: > > save_stack+0x1b/0x80 mm/kasan/common.c:72 > > set_track mm/kasan/common.c:80 [inline] > > kasan_set_free_info mm/kasan/common.c:337 [inline] > > __kasan_slab_free+0x117/0x160 mm/kasan/common.c:476 > > slab_free_hook mm/slub.c:1444 [inline] > > slab_free_freelist_hook mm/slub.c:1477 [inline] > > slab_free mm/slub.c:3024 [inline] > > kmem_cache_free+0x9b/0x360 mm/slub.c:3040 > > kfree_skbmem net/core/skbuff.c:622 [inline] > > kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:616 > > __kfree_skb net/core/skbuff.c:679 [inline] > > kfree_skb net/core/skbuff.c:696 [inline] > > kfree_skb+0x102/0x3d0 net/core/skbuff.c:690 > > htc_connect_service.cold+0xa9/0x109 drivers/net/wireless/ath/ath9k/htc_hst.c:282 > > ath9k_wmi_connect+0xd2/0x1a0 drivers/net/wireless/ath/ath9k/wmi.c:265 > > ath9k_init_htc_services.constprop.0+0xb4/0x650 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146 > > ath9k_htc_probe_device+0x25a/0x1d80 drivers/net/wireless/ath/ath9k/htc_drv_init.c:959 > > ath9k_htc_hw_init+0x31/0x60 drivers/net/wireless/ath/ath9k/htc_hst.c:501 > > ath9k_hif_usb_firmware_cb+0x26b/0x500 drivers/net/wireless/ath/ath9k/hif_usb.c:1187 > > request_firmware_work_func+0x126/0x242 drivers/base/firmware_loader/main.c:976 > > process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 > > worker_thread+0x96/0xe20 kernel/workqueue.c:2410 > > kthread+0x318/0x420 kernel/kthread.c:255 > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > > The buggy address belongs to the object at ffff8881d68163c0 > > which belongs to the cache skbuff_head_cache of size 224 > > The buggy address is located 212 bytes inside of > > 224-byte region [ffff8881d68163c0, ffff8881d68164a0) > > The buggy address belongs to the page: > > page:ffffea00075a0580 refcount:1 mapcount:0 mapping:ffff8881da16b400 index:0x0 > > flags: 0x200000000000200(slab) > > raw: 0200000000000200 ffffea00072b75c0 0000000300000002 ffff8881da16b400 > > raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 > > page dumped because: kasan: bad access detected > > > > Memory state around the buggy address: > > ffff8881d6816380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb > > ffff8881d6816400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > >ffff8881d6816480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc > > ^ > > ffff8881d6816500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8881d6816580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > > ================================================================== > > Trust the usb driver to do its work with skb cared after a successful > send, even in case of timeout. > > --- a/drivers/net/wireless/ath/ath9k/htc_hst.c > +++ b/drivers/net/wireless/ath/ath9k/htc_hst.c > @@ -279,7 +279,6 @@ int htc_connect_service(struct htc_targe > if (!time_left) { > dev_err(target->dev, "Service connection timeout for: %d\n", > service_connreq->service_id); > - kfree_skb(skb); > return -ETIMEDOUT; > } Hi Hillf, I think this is the 50th patch I see from you sent as a reply to a syzbot report without a clear indication what to do with it. You either need to issue a syz test command if you want your patch to be tested by syzbot, or send the patch property if you want to get it picked up by maintainers. I really appreciate you looking at the reports and working on fixing the bugs, but just sending patches as replies is pointless. Thanks!
