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Roger Quadros 163be6ff77 usb: gadget: udc: core: Fix segfault if udc_bind_to_driver() for pending driver fails
If a gadget driver is in the pending drivers list, a UDC
becomes available and udc_bind_to_driver() fails, then it
gets deleted from the pending list.
i.e. list_del(&driver->pending) in check_pending_gadget_drivers().

Then if that gadget driver is unregistered,
usb_gadget_unregister_driver() does a list_del(&driver->pending)
again thus causing a page fault as that list entry has been poisoned
by the previous list_del().

Fix this by using list_del_init() instead of list_del() in
check_pending_gadget_drivers().

Test case:

- Make sure no UDC is available
- modprobe g_mass_storage file=wrongfile
- Load UDC driver so it becomes available
	lun0: unable to open backing file: wrongfile
- modprobe -r g_mass_storage

[   60.900431] Unable to handle kernel paging request at virtual address dead000000000108
[   60.908346] Mem abort info:
[   60.911145]   ESR = 0x96000044
[   60.914227]   Exception class = DABT (current EL), IL = 32 bits
[   60.920162]   SET = 0, FnV = 0
[   60.923217]   EA = 0, S1PTW = 0
[   60.926354] Data abort info:
[   60.929228]   ISV = 0, ISS = 0x00000044
[   60.933058]   CM = 0, WnR = 1
[   60.936011] [dead000000000108] address between user and kernel address ranges
[   60.943136] Internal error: Oops: 96000044 [#1] PREEMPT SMP
[   60.948691] Modules linked in: g_mass_storage(-) usb_f_mass_storage libcomposite xhci_plat_hcd xhci_hcd usbcore ti_am335x_adc kfifo_buf omap_rng cdns3 rng_core udc_core crc32_ce xfrm_user crct10dif_ce snd_so6
[   60.993995] Process modprobe (pid: 834, stack limit = 0x00000000c2aebc69)
[   61.000765] CPU: 0 PID: 834 Comm: modprobe Not tainted 4.19.59-01963-g065f42a60499 #92
[   61.008658] Hardware name: Texas Instruments SoC (DT)
[   61.014472] pstate: 60000005 (nZCv daif -PAN -UAO)
[   61.019253] pc : usb_gadget_unregister_driver+0x7c/0x108 [udc_core]
[   61.025503] lr : usb_gadget_unregister_driver+0x30/0x108 [udc_core]
[   61.031750] sp : ffff00001338fda0
[   61.035049] x29: ffff00001338fda0 x28: ffff800846d40000
[   61.040346] x27: 0000000000000000 x26: 0000000000000000
[   61.045642] x25: 0000000056000000 x24: 0000000000000800
[   61.050938] x23: ffff000008d7b0d0 x22: ffff0000088b07c8
[   61.056234] x21: ffff000001100000 x20: ffff000002020260
[   61.061530] x19: ffff0000010ffd28 x18: 0000000000000000
[   61.066825] x17: 0000000000000000 x16: 0000000000000000
[   61.072121] x15: 0000000000000000 x14: 0000000000000000
[   61.077417] x13: ffff000000000000 x12: ffffffffffffffff
[   61.082712] x11: 0000000000000030 x10: 7f7f7f7f7f7f7f7f
[   61.088008] x9 : fefefefefefefeff x8 : 0000000000000000
[   61.093304] x7 : ffffffffffffffff x6 : 000000000000ffff
[   61.098599] x5 : 8080000000000000 x4 : 0000000000000000
[   61.103895] x3 : ffff000001100020 x2 : ffff800846d40000
[   61.109190] x1 : dead000000000100 x0 : dead000000000200
[   61.114486] Call trace:
[   61.116922]  usb_gadget_unregister_driver+0x7c/0x108 [udc_core]
[   61.122828]  usb_composite_unregister+0x10/0x18 [libcomposite]
[   61.128643]  msg_cleanup+0x18/0xfce0 [g_mass_storage]
[   61.133682]  __arm64_sys_delete_module+0x17c/0x1f0
[   61.138458]  el0_svc_common+0x90/0x158
[   61.142192]  el0_svc_handler+0x2c/0x80
[   61.145926]  el0_svc+0x8/0xc
[   61.148794] Code: eb03003f d10be033 54ffff21 a94d0281 (f9000420)
[   61.154869] ---[ end trace afb22e9b637bd9a7 ]---
Segmentation fault

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2019-08-28 13:04:59 +03:00
arch powerpc fixes for 5.3 #3 2019-08-04 10:30:47 -07:00
block for-linus-20190726-2 2019-07-26 19:20:34 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
Documentation HMM patches for 5.3-rc 2019-07-30 12:54:44 -07:00
drivers usb: gadget: udc: core: Fix segfault if udc_bind_to_driver() for pending driver fails 2019-08-28 13:04:59 +03:00
fs Merge tag 'xfs-5.3-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux 2019-08-03 10:43:44 -07:00
include usb: Add definitions for the USB2.0 hub TT requests 2019-08-12 08:54:49 +03:00
init Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
ipc Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
kernel memremap: move from kernel/ to mm/ 2019-08-03 07:02:01 -07:00
lib Kbuild fixes for v5.3 (2nd) 2019-08-04 10:16:30 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm memremap: move from kernel/ to mm/ 2019-08-03 07:02:01 -07:00
net tcp: be more careful in tcp_fragment() 2019-07-21 20:41:24 -07:00
samples treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers again 2019-07-25 11:05:10 +02:00
scripts kconfig: Clear "written" flag to avoid data loss 2019-08-04 12:44:15 +09:00
security selinux/stable-5.3 PR 20190801 2019-08-02 18:40:49 -07:00
sound sound fixes for 5.3-rc3 2019-08-02 08:53:34 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-08-03 10:58:46 -07:00
usr kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test 2019-07-23 10:45:46 +02:00
virt Documentation: move Documentation/virtual to Documentation/virt 2019-07-24 10:52:11 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig
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.gitignore .gitignore: Add compilation database file 2019-07-27 12:18:19 +09:00
.mailmap MAINTAINERS: Update my email address 2019-07-22 14:57:50 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Remove references to dead website. 2019-07-19 12:22:04 -07:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: Add Geert as Renesas SoC Co-Maintainer 2019-08-04 10:23:23 -07:00
Makefile Linux 5.3-rc3 2019-08-04 18:40:12 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.