ced21a4c72
The skb is consumed by htc_send_epid, so it needn't release again. The case reported by syzbot: https://lore.kernel.org/linux-usb/000000000000590f6b05a1c05d15@google.com usb 1-1: ath9k_htc: Firmware ath9k_htc/htc_9271-1.4.0.fw requested usb 1-1: ath9k_htc: Transferred FW: ath9k_htc/htc_9271-1.4.0.fw, size: 51008 usb 1-1: Service connection timeout for: 256 ================================================================== 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 ffff8881d0957994 by task kworker/1:2/83 Call Trace: kfree_skb+0x32/0x3d0 net/core/skbuff.c:692 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 Allocated by task 83: 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 0: kfree_skb+0x102/0x3d0 net/core/skbuff.c:690 ath9k_htc_txcompletion_cb+0x1f8/0x2b0 drivers/net/wireless/ath/ath9k/htc_hst.c:356 hif_usb_regout_cb+0x10b/0x1b0 drivers/net/wireless/ath/ath9k/hif_usb.c:90 __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 Reported-and-tested-by: syzbot+9505af1ae303dabdc646@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Link: https://lore.kernel.org/r/20200404041838.10426-2-hqjagain@gmail.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.